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View Full Version : Wishing a warm welcome to Rythmik Audio



davef
10-30-2008, 09:20 AM
It has been a long time coming… 18 months ago I sent a simple email to a humble and honest electrical engineer requesting some information about his unique products. Time passed and I got to know this engineer well and quickly came to realize that he and I shared some unique traits; a true passion for sound quality, and of even more importance, an honesty and integrity rarely found in this industry.

That initial email led to hundreds of correspondences, months of testing and negotiations that would make even the most seasoned politicians cringe. After surveying our customer base, the overwhelming majority desired a subwoofer that placed sound quality as the highest priority. Size, output and looks all took a backseat to performance.

You asked for it and together with someone I am proud to call my friend, we have delivered it to you in spades.

We are honored to now carry the new line of Rythmik Direct Servo subwoofers (http://www.ascendacoustics.com/pages/products/subs/subintro.html). I have spent countless hours testing and measuring these units, tearing them apart component by component and most importantly, simply listening to them. As some of you know, I have been involved with subwoofers since their early days (22+ yrs ago). I have shied away from introducing our own line simply because of how the subwoofer market has changed since the early days. Today, it is all about inexpensive amplification – which manufacturer can obtain the most wattage at the least cost and then develop a woofer to make best use of this power. Make no mistake about it, the amplifiers and woofers used in the majority of subwoofers out there are far from what I or anyone in the know would consider “audiophile” quality. They are designed for maximum output at the last expense.

Rythmik subwoofers are a different breed altogether. Every component is designed for sound quality first. Even without their patented Direct Servo technology, which brings sound quality to an unmatched level, the amplifier and woofer are leagues above any competing units (and yes, I have a factory full of competing subwoofers to prove it ;) ).

I can go on and on about these units and how they are the perfect match to our Sierra-1, but rather than have me ramble on and on, I want to introduce you to my dear friend, Chih-Shun (Brian) Ding. I must make one additional point, Brian is not an audio hobbyist turn subwoofer designer. Unlike many subwoofer designers these days, Brian has a PHD in Electrical Engineering from USC and you simply won’t find a more knowledgeable engineer or someone so willing to share his passion and intellect with anyone interested.

This forum section will be dedicated to Rythmik subwoofers and it is here where you can ask questions and get direct answers from Brian himself. All I ask is that you show the same patience and respect that you have given me over the years. Since one of the goals here is to create a section whereby anyone can find more detailed info regarding Rythmik subwoofers, please post new questions in new separate threads. Brian will say hello later today and do his best to answer questions.

Brian, it has been my sincere pleasure and honor, let me be the first to welcome you!

Enjoy!!!

kibe
10-30-2008, 10:52 AM
Congratulations Dave! The subs look terrific and it's nice to see a long project come to fruition! I have just have to keep saving up for one.... The prices as always with Ascend offerings look extremely competitive. I can't wait to read some reviews.

ccotenj
10-30-2008, 10:54 AM
well... this is an interesting development... :)

i don't suppose we could get some custom veneers? a pair of those 15's would find their way into my room if i could get a bamboo veneer to match the sierra's... :D

venomxtf
10-30-2008, 10:57 AM
Hi Dave,

It's great to finally hear the subwoofer news. I have waited years for you to announce something before purchasing from some other company.

Can't wait to hear more details from Brian!

kylem
10-30-2008, 10:59 AM
How exciting! Too bad I just bought my Epik six months ago or I'd be jumping all over this.

mazersteven
10-30-2008, 10:59 AM
Interesting News

It will be great for people to purchase Ascend speakers in a package complete with subwoofer. :D

Derek
10-30-2008, 11:03 AM
Wow. Very cool.

Brian is a great guy. He worked with Brian Bunge to tune the rythmik amp specifically for the custom sub Brian built for me years ago.

Congrats on the new product. Now I know where to get my next sub if I ever need an upgrade.

Derek

Gov
10-30-2008, 11:06 AM
Just when I thought I was putting the subwoofer upgrade to bed, then this comes along :eek::eek: Now, what to do!!!!!!

curtis
10-30-2008, 11:06 AM
This is great news......from the last couple of months, you all know what I think of the Rythmik sound.

Congrats Dave...good move!

Pilk
10-30-2008, 11:08 AM
Need a package price for those who have already purchased Ascend speakers or for those who wish to put together a system. And...a price for duals...must have duals.

drewface
10-30-2008, 11:16 AM
congrats dave and brian! i have heard a lot of good things about Rythmik in the past, and i look forward to hearing more details about these subs. i'm pretty sure one of them will find its way into my home in the not too distant future...

clarke68
10-30-2008, 11:19 AM
Congratulations to both Ascend and Rhythmik!

It's funny, I've been lurking on Rhythmik's website ever since Dave made a nice comment about them in the "talking about subwoofers" thread. Been plotting & scheming ever since, and I can say with all honesty that the D-15 is exactly what I want.

Well, almost...any chance that will be offered in the walnut finish? Or better yet...bamboo veneer?

FallenCow
10-30-2008, 11:19 AM
very interesting development... I'm not familiar with these subs, anyone want to give their opinion on them? What are the differences between the 3 and how would they compare to HSU (i have a VTF2-MK3 paired with my sierras)?

ccotenj
10-30-2008, 11:21 AM
Or better yet...bamboo veneer?

ok dave, that's two of us now who want the bamboo... :D

clarke68
10-30-2008, 11:25 AM
ok dave, that's two of us now who want the bamboo... :DY'know ccotenj, Dave probably has a couple laying around from all the experimenting he was doing. How long do you think we'll need to camp out in this thread before he offers them to us? :cool:

lokimydog
10-30-2008, 11:33 AM
Hi Dave,

Will the subs be available for local pickup to save on shipping. Also, any pre-order specials :) to go with this fantastic announcement. I'm in the market for a pair of HSU ULS-15's but that might change real soon.

ebh
10-30-2008, 11:35 AM
called it! Sorta. :p

http://forum.ascendacoustics.com/showpost.php?p=21726&postcount=12

http://forum.ascendacoustics.com/showpost.php?p=21741&postcount=16

can't wait to order one!

edit: also would love a bamboo veneer if there is any way to do that. otherwise it might be piano black for me.

Gov
10-30-2008, 11:41 AM
Dave will be be carrying the F12 (non SE)? What is the diiference besides the finish?

ccotenj
10-30-2008, 11:42 AM
Y'know ccotenj, Dave probably has a couple laying around from all the experimenting he was doing. How long do you think we'll need to camp out in this thread before he offers them to us? :cool:

kinda like jake and elwood going to get mr. fabulous...

"how much for the bamboo sub? how much for your little subs?"...

:D

clarke68
10-30-2008, 12:09 PM
kinda like jake and elwood going to get mr. fabulous...Sell me your children!!! :cool:

ccotenj
10-30-2008, 01:04 PM
Sell me your children!!! :cool:

LOL! still one of my favorite movies of all time... :)

but seriously... i wouldn't really even need the 15's... i'd settle for dual 12's in bamboo... put one in the front and one in the back of the room... i could get a reasonable chunk of the cost back by selling my paradigm...

it's his own fault that we want the bamboo finish... :p

blindtom
10-30-2008, 01:09 PM
Very nice, but two weeks too late for me. :-((

clarke68
10-30-2008, 01:23 PM
it's his own fault that we want the bamboo finish... :pSerious. If he didn't make speakers that look so freaking cool, we wouldn't want subwoofers to match them!

Actually, what I like best about the D15 is that it could pass as an end table. Of course, I still want two...gotta have symmetry. :eek:

Blake1214
10-30-2008, 01:31 PM
This is great news!!! I almost pulled the trigger to go with the HSU UL-15's but decided to wait until I hear more about what Dave will be offering. Anyone know how the F-15 compares to the UL-15's? Any chance of getting the F-15 in piano black (F-15 SE) to match our PB Sierras?

Mag_Neato
10-30-2008, 01:36 PM
This is great news!!! I almost pulled the trigger to go with the HSU UL-15's but decided to wait until I hear more about what Dave will be offering. Anyone know how the D-15 compares to the UL-15's? Any chance of getting the D-15 in piano black (D-15 SE) to match our PB Sierras?

Piano black IS the standard finish.

Blake1214
10-30-2008, 01:39 PM
Piano black IS the standard finish.

Sorry, I meant the F15. Right now, it's only in walnut or black oak.

Mag_Neato
10-30-2008, 01:42 PM
Sorry, I meant the F15. Right now, it's only in walnut or black oak.

Ah. The finish is most likely the main factor in the price difference between the F15 and the D15. Other than one being front firing and the other down firing. I would think they are equal performance-wise.

Blake1214
10-30-2008, 01:57 PM
Ah. The finish is most likely the main factor in the price difference between the F15 and the D15. Other than one being front firing and the other down firing. I would think they are equal performance-wise.

Yup, since both uses the same components. The reason I'm trying to stay away from down firing subs is because I live in a high rise condo. I currently have the Sierras matched with a SVS PC plus. I don't know the physics behind it but tested with my neighbors downstairs using down firing vs front firing subs. They are able to hear the bass travel of the SVS downfiring a lot more in their unit even though it sounds the same in my condo. The weird thing is, the PC plus even has a base plate. So to prevent myself from worrying so much everytime I watch a movie with bass, I've decided to just get 2 front firing subs. I would definitely want it in PB finish to go with my PB Sierras though.

lokimydog
10-30-2008, 02:01 PM
Hi Dave,

I know this is kind of early but I have to ask. Would you consider making a front firing sub with an 15" driver in PB (F15SE)? This woofer is too pretty to be pointed downwards and not seen. I want to see this woofer move when it shakes my home.

ebh
10-30-2008, 02:01 PM
Yup, since both uses the same components. The reason I'm trying to stay away from down firing subs is because I live in a high rise condo. I currently have the Sierras matched with a SVS PC plus. I don't know the physics behind it but tested with my neighbors downstairs using down firing vs front firing subs. They are able to hear the bass travel of the SVS downfiring a lot more in their unit even though it sounds the same in my condo. The weird thing is, the PC plus even has a base plate. So to prevent myself from worrying so much everytime I watch a movie with bass, I've decided to just get 2 front firing subs. I would definitely want it in PB finish to go with my PB Sierras though.

Weird, I always thought it wouldn't make a difference, most bass being omnidirectional and all. You could try getting a subdude to place underneath.

Blake1214
10-30-2008, 02:14 PM
Weird, I always thought it wouldn't make a difference, most bass being omnidirectional and all. You could try getting a subdude to place underneath.

Thought about that too. But keep in mind, my condo is a miniscule 927 sq ft. If you've seen these subs in person, you'll know adding another few inches to their already water tank dimension will truly warf my living area.

Besides, that won't give me an excuse to upgrade my HT. :cool:

Dave, besides the F15 in PB finish, any plans on a package discount for returning customers or people who buys more than one sub?

azanon
10-30-2008, 03:37 PM
I'm glad to see that this time, a choice was made to go with a sub that focuses primarily on sound quality. I hope this is the focal point of comments about this sub at 3rd party forums like AVS.

RythmikAudio
10-30-2008, 08:22 PM
Thanks for the introduction from David. Direct servo subwoofers may be relatively new for most members here. So please feel free to ask questions. I should be able to visit to forum once to twice a day. If you don't get reply in a timely manner, feel free to send me PM to remind me. Secondly, my writing style can be very dry and too technical. If that is the case, please feel free to remind me.

Two questions that I have heard so far:
1) F12 is same as F12SE except finish. Currently we have very limited inventory for F12.
2) F15 piano finish is still under evaluation. So I cannot give definitive answer in terms of which driver/amplifier will be used.

DirectServo subwoofers have been in the market for quite a few years, although in a slightly different form. The design objective has always been musicality first and within that boundary try to get the highest possible SPL. With that being said, for majority of customers I am pretty confident that the SPL output is sufficient for HT usage. Also, we have a very flexible extension filter setting that allow us the trade off SPL with extension. For those who would like to get higher SPL, please set that to 28hz/low damping, or 20hz/low damping. For the most musical sound, 14hz high damping is what most will use.

clarke68
10-30-2008, 09:11 PM
Welcome to the forum, Brian!

It'll be great to have you around...I always appreciate a chance to pick the brain of people who know how to get good sound. Question for you about the following quote:


The design objective has always been musicality first and within that boundary try to get the highest possible SPL. For the most musical sound, 14hz high damping is what most will use.

What is "musicality" from an engineering perspective? How do you determine when a subwoofer is "musical" or not?

This term gets used quite a bit in the audio press without a clear definition. I use it often myself to describe sound that is realistic & emotionally engaging. I know it when I hear it, but I don't necessarily know when I don't hear it (hopefully that makes sense). Still, I have no idea how it could be produced (or not) or measured using the tools you have as an engineer, or what would determine the "boundaries" of musicality that you mention.

davef
10-30-2008, 10:12 PM
Welcome to the forum, Brian!

It'll be great to have you around...I always appreciate a chance to pick the brain of people who know how to get good sound. Question for you about the following quote:

What is "musicality" from an engineering perspective? How do you determine when a subwoofer is "musical" or not?

This term gets used quite a bit in the audio press without a clear definition. I use it often myself to describe sound that is realistic & emotionally engaging. I know it when I hear it, but I don't necessarily know when I don't hear it (hopefully that makes sense). Still, I have no idea how it could be produced (or not) or measured using the tools you have as an engineer, or what would determine the "boundaries" of musicality that you mention.

Great question Clarke and I too look forward to Brian's response.

For me, I define "musicality" when referring to a subwoofer as the unit's ability to present tonal accuracy and, more importantly, to be able to reproduce and clearly distinguish multiple tones at the same time. For example, reproduction of a bass guitar note at the same time as a pipe organ. This is more complicated than it might seem due to high-excursion demands where the woofer loses motor force and control. Imagine a woofer reproducing a 20Hz tone with massive excursion demands while also having to reproduce a 60Hz tone at the same time. The 20Hz tone can have a tremendous negative impact on that more subtle 60Hz tone, especially at high output levels, where the 60Hz tone will suffer a loss of detail or be “glossed over" completely. Often referred to as "one note bass".

One note bass is often quite adequate for home theater because most people are more concerned with impact and room rumbling deep bass and they don’t care about subtle details (nothing really subtle about a train wreck ;) ) However, this is not acceptable for music listening, IMO, where much of the music detail can be lost. It is in this area where Direct Servo excels, the amplifier is constantly monitoring both the velocity and excursion of the woofer and errors are instantly corrected at the speed of light, which is faster than sound so they are corrected before you hear them.

Imagine shooting a high-power rifle at two distinct targets and you must fire each shot within a millisecond of each other. The very best rifleman might be able to hit that first target, but the kick of the first shot will prevent any chance of that second shot reaching the target. What if that rifleman had to fire 5 or 6 shots within 1 or 2 milliseconds? What a mess. Now imagine if the flight of each of those bullets was controlled by a high speed computer such that they would be directed to the target regardless of any external variables or operator error. That is the difference servo control represents.

The woofer is precisely controlled and every note is reproduced cleanly without a loss of detail. The result is what I define as "musicality" :D

RythmikAudio
10-30-2008, 10:43 PM
What is "musicality" from an engineering perspective? How do you determine when a subwoofer is "musical" or not?

This term gets used quite a bit in the audio press without a clear definition. I use it often myself to describe sound that is realistic & emotionally engaging. I know it when I hear it, but I don't necessarily know when I don't hear it (hopefully that makes sense). Still, I have no idea how it could be produced (or not) or measured using the tools you have as an engineer, or what would determine the "boundaries" of musicality that you mention.

My 5th grade son has been learning piano for about 7 years now. I constantly comparing between how he and his teacher playing the same piece of music and try to communicate with him what he should pay attention to when he practices at home. This analysis mode, plus other experiences listening to stereo systems makes me think more about musicality. For me, musicality is the correct combination of contrast (some call it dynamics), articulation, and pace that give us goosebumps and make us tap our foot. Our company's name should remind you this :-) Musicality is not the same as sound quality where it is more about the texture of the sound even though they can be related in sound systems. It is like my son and his teacher playing on the same piano. Sound quality wise, the two are exactly the same, and yet one is more musical than another. Another example is that a Yamaha piano can be as musical as a Steinway in the right hands and yet their sound texture is very different. I have heard some good sound systems with pretty good sound texture and yet it fails to convey the musicality (for instance my ULD15-II).

To reproduce the correct contrast in a sound system, it needs to have the same monotonicity time over time. Low memory effect is the key here. In my son's playing, he has a weak 4th and 5th fingers. So whenever he uses 3rd finger on the current note, you can expect 50% of the time, the next note to be played not as loud as it should be. That is a form of memory effect. That is, the strength of current note depends on the past history of his fingering position. Even though in sound systems, the memory effect is not as bad as in my son's case, But it can still be quite audible. In audio's history, we have 16ohms LS3/5A as a proof. The 16ohms LS3/5A was a success for BBC. Later they come up with a new revision with 8ohms impedance. However, the sound was audibly less dynamic (when I sold my LS3/5A, some potential buyers told me they were only interested in the 16ohm version and mine is not). For those not knowing the inside story may think 16ohms is less a burden to the amplifier and therefore produces a better sound. Actually it is not the case, the root cause was later traced to the new surround material on the 8ohm version. That surround material has a pretty high "creep" effect which is a form of memory effect. In speakers there are at least two forms of memory effects: one is thermal and one is mechanical, such as spider/surround.


Articulation is more related to the time domain response with minimal ringing and minimal boxy sound. One note can be clearly separated from the next notes. In my son's playing, he needs to lift his fingers higher. In sound system, the sound needs to start and stop very fast. The start related to (BL)^2/Re, and the stop is determined by the Q value. A boxy sound from the enclosure can easily make the sound muddy.

Pace again is largely determined by the memory effects. In my sons playing, his 4th and 5th finger is not only weaker, but also slightly slower.

In conclusion, we have a couple of things here: 1) low memory effect, 2) low Q value for the system, and 3) minimal boxy sound. It is not a coincident that our servo subwoofers address all of them.

Mag_Neato
10-31-2008, 05:49 AM
Welcome, Brian! I have been enjoying my DIY'd DS12 for over a year now. I appreciate you taking the time to speak with me on the phone regarding the proper amount of polyfil to use in my enclosure and other questions about the operation of the sub.

I noticed on the new subs here that a 1-band PEQ has been included as well as a defeatable rumble filter. I was curious if the power output of the amp has been increased (370W) over the amp I have from a year ago without the PEQ/rumble filter? Also, has the driver changed since then?

Just curious. I am completely happy with the performance, but if there is an upgrade available............:D

merrymaid520
10-31-2008, 05:54 AM
Welcome Brain!

In the other thread we chatted about not using the downfiring D15 on wood subfloors. The F series would truly be perfect in the piano fininsh for alot of us. If its not feasible or along way out, can the D15 be turned on its side?(with the amp up of course;)

I have been chating with Dave F about your subs and thought I would run this past you also. My current subs is in a 17x17 living area with virtually no walls opening into a 12x18 kitche, then a 17x17 dining room. Will the 15" be sufficient in terms of HT performance. I dont listen at ref levels nor have I every bottomed my current SVS PC Ultra 12" out yet.

Thanks!
Brandon

RythmikAudio
10-31-2008, 06:35 AM
Welcome, Brian! I have been enjoying my DIY'd DS12 for over a year now. I appreciate you taking the time to speak with me on the phone regarding the proper amount of polyfil to use in my enclosure and other questions about the operation of the sub.

I noticed on the new subs here that a 1-band PEQ has been included as well as a defeatable rumble filter. I was curious if the power output of the amp has been increased (370W) over the amp I have from a year ago without the PEQ/rumble filter? Also, has the driver changed since then?

Just curious. I am completely happy with the performance, but if there is an upgrade available............:D

Ed,

The amplifier output is still the same. Only the preamp stage has been redesigned. PEQ is valuable if your room has a significant room mode. Rumble filter is more for those who likes to play really loud or have LP players. If you feel you would be more comfortable with an upgrade, please send me an email and we will figure out what to do.

-Brian

RythmikAudio
10-31-2008, 06:50 AM
Welcome Brain!

In the other thread we chatted about not using the downfiring D15 on wood subfloors. The F series would truly be perfect in the piano fininsh for alot of us. If its not feasible or along way out, can the D15 be turned on its side?(with the amp up of course;)

I have been chating with Dave F about your subs and thought I would run this past you also. My current subs is in a 17x17 living area with virtually no walls opening into a 12x18 kitche, then a 17x17 dining room. Will the 15" be sufficient in terms of HT performance. I dont listen at ref levels nor have I every bottomed my current SVS PC Ultra 12" out yet.

Thanks!
Brandon

The comparison of sealed vs vented subwoofers is a bit difficult because there are weakness in each. The vented box would have more output between 18hz to 40hz band only (EDIT: I made a mistake earlier), and lose to sealed subwoofer below port tuning frequency (for the rumble effect). But I have a few PC Ultra customers, after they hear the sound of our subwoofers, they are pretty much surprised there is such a huge difference. One customer, Kevin, even said our sound is just cleaner, there is no other way to describe it. If you are into sound quality and not into SPL competition, our sealed 15" have plenty output.

BTW, I won't recommend turn D15SE side way, it just doesn't look good. The reason we are still evaluating what to do with a piano finish F15 is that we can use a different driver. If there is any improvement in SPL we'd want to do, the reward is higher if it is done on 15".

-Brian

Mag_Neato
10-31-2008, 07:20 AM
Thanks Brian!

I was just curious, mostly, about the power output. If that is the same then I don't see a need to change the amp.

I have an LD player. It is nicely packed away in it's original box in a closet:cool:

I do like the new sub enclosures. I still need to figure out some sort of grill for my unfinished MDF box:(

merrymaid520
10-31-2008, 08:27 AM
The comparison of sealed vs vented subwoofers is a bit difficult because there are weakness in each. The vented box would have more output between 25hz to 40hz band only, and lose to sealed subwoofer below port tuning frequency (for the rumble effect). But I have a few PC Ultra customers, after they hear the sound of our subwoofers, they are pretty much surprised there is such a huge difference. One customer, Kevin, even said our sound is just cleaner, there is no other way to describe it. If you are into sound quality and not into SPL competition, our sealed 15" have plenty output.

BTW, I won't recommend turn D15SE side way, it just doesn't look good. The reason we are still evaluating what to do with a piano finish F15 is that we can use a different driver. If there is any improvement in SPL we'd want to do, the reward is higher if it is done on 15".

-Brian

Is there a reason why you are considering a different driver for the F15 rather than just offering it in a piano finish? If I am in the market now, having carpet over wood sub-floor what do you recomend I do?

Brandon

curtis
10-31-2008, 09:11 AM
Is there a reason why you are considering a different driver for the F15 rather than just offering it in a piano finish? If I am in the market now, having carpet over wood sub-floor what do you recomend I do?
Did you do the "stomp" test that Brian mentioned in that area?

merrymaid520
10-31-2008, 09:28 AM
Did you do the "stomp" test that Brian mentioned in that area?

I am planning on "stomping around" when I get home tonight. I will report back with all of the scientific data I can gather;)

clarke68
10-31-2008, 11:02 AM
For me, musicality is the correct combination of contrast (some call it dynamics), articulation, and pace that give us goosebumps and make us tap our foot.Interesting answer, Brian, thanks!

Sounds like what you're describing is what a lot of people call "PRaT" (pace, rhythm & timing), but I think we're talking about the same thing when you describe the effect it has on the listening experience.

Very interesting (and encouraging) that you have each subjective aspect of musical sound mapped to a t/s parameter or other hardware component. I'm really looking forward to hearing what your subs can do!

rmj
10-31-2008, 03:31 PM
Subs look great...love the pb finish. Funny thing is, since I'm based in TX, it looks like it would be cheaper to purchase from Ascend (899+50 s/h) than picking one up from Rythmik in Austin (899+$74 due to 8.125% tax)!

GirgleMirt
10-31-2008, 09:22 PM
Wow! How did I miss this? Congrats to Dave and Brian! :D

I've dealt with Brian in the past, problems with Canada Post with an amp plate, and Brian was absolutely great to deal with. Great guy! I really think this partnership with Ascend and Rythmik is absolutely fantastic. I don't think it was a coincidence that Rythmik stood out at the time I was looking for sub parts a couple years ago, as they always somewhat seemed to fit with the Ascend philosophy. At the time the servo was more than I wanted to spend, but if I built/bought a new sub, it would definitely be a servo, and Brian/Rythmik is where it's at.

Sealed and servo is where it's at for musical subs. Hell, I even said so in the "what sub do you guys want"! Well sort of...

So I guess what I'm asking is not to make a monstrous looking sub, bit of aesthetics is more important than type of finish for me In my case, I'd like smaller footprint and maybe higher, but that's not so important.

One thing I learned with my sealed sub, you want a flat FR... Sealed, that probably means EQ or servo, but I'll leave the designing to you
[...]
Words like Servo or digital amps are floating in my mind...
And Servo we got! Not to mention great looking subs... Piano Black looks great, probably fantastic match with the Sierras!

Seriously, if I could have chosen, or written the story myself, couldn't have done better, Ascend and Rythmik together, absolutely fantastic. Two great companies and individuals, imho, couldn't have been a better match!

Congrats!

muzz
11-01-2008, 10:47 AM
Wow

Great choice Dave!!

I have been enjoying my DS12 for awhile now, and have absolutely no regrets with the purchase I made.
Teamed up with my Sierras, the DS12 sounds fantastic.
Brian was very easy to talk to when I was getting ready to order, just like you were Dave.

Welcome to the forum Brian!

RythmikAudio
11-01-2008, 10:48 AM
Interesting answer, Brian, thanks!

Sounds like what you're describing is what a lot of people call "PRaT" (pace, rhythm & timing), but I think we're talking about the same thing when you describe the effect it has on the listening experience.

Very interesting (and encouraging) that you have each subjective aspect of musical sound mapped to a t/s parameter or other hardware component. I'm really looking forward to hearing what your subs can do!

I want to clarify a bit though because if we just focus on pace, rhythm and timing, it may sound very mechanical. If we analyze music techniques such as portamento (techniques of gliding between notes in singing or strings), what does it take to faithfully reproduce that type of sound? I think it is contrast and articulation (and not so much of rhythm as defined as periodic beat). Yes, human voice and strings are two of my favorite instruments, so my view may be biased.

millerwill
11-01-2008, 11:40 AM
I was looking at these Rythmik subs on their website, and the frequency response in the specs seem to be the identical curve for all 3. Is that possible?

GirgleMirt
11-01-2008, 12:35 PM
Yep, due to servo :)

See here: http://www.rythmikaudio.com/technology.html


*1. Amplified signal

The plate amplifier receives a signal which is filtered on the pre-amp board to achieve correct integration. The power amplifier sends a signal to the driver.

*2. Cone excursion

As the amplified signal passes through the voice coil, the cone moves.

*3. Correction signal

A very thin sensing coil is attached to the voice coil. As the cone moves, a signal is generated. This signal is used to accurately track the movement of the cone. Effectively the sensing coil is a specialized microphone which measures the precise output of the driver.

*4. Feedback

The correction signal is fed back into the summing points of the amplifier. It is compared to the original signal and corrections are made without the use of any active circuits.

*5. Corrected signal is accurately reproduced

The driver now reproduces a signal that is corrected. The sources of distortion which plague other subwoofers are dramatically reduced.

RythmikAudio
11-01-2008, 02:32 PM
I was looking at these Rythmik subs on their website, and the frequency response in the specs seem to be the identical curve for all 3. Is that possible?

I need to discuss with the web designer. I may not have communicated them well with him. I have published DS1200 and DS1500 curves before. They are almost idential below 60hz for the reason GirgleMirt mentioned. Above 60hz, the roll-off is different for 12" and 15" due to the magnitude of inductance are different in those two models. Anyway, I will correct that as soon as possible.

BTW, Paul Spencer has helped me designed these webs and he has done a great job. He is also an audiophile and owns a pair of directservo subs.

There is a historical reason for me try to clone the frequency response. When I was designing DS15 (our first 15" driver), I had problem deciding what roll-off contouring I should use for the low end. I want it sound as close to our 12" as possible. I constantly switch between the two in my listening room. And I struggled for a month and then the face of Bob Carver gave me a hint and then I decide I should clone the frequency response as much as possible. Then if there is any difference, it is due to driver and not due to frequency reponse. Ever since then, that is our design philosiphy and it has helped us to design good driver and subwoofer. Whenever a driver does not sound as dynamic, we go look at the spider, the surround, and all the components that can affect sound quality.

For those not familiar with what Bob Carver has done, he is the first one successfully implemented transfer function cloning for pre-amp and power amps and demostrated in front of a panel of audiophiles, not just once, but twice. The second time was from Stereophile. The first time was from TAS. Stereophile felt the first event was not carefully designed so they gave him a tube power amplifier wrapped in a box or case that Bob cannot see what is inside. The rest is history.

-Brian

clarke68
11-01-2008, 03:13 PM
I want to clarify a bit though because if we just focus on pace, rhythm and timing, it may sound very mechanical. If we analyze music techniques such as portamento (techniques of gliding between notes in singing or strings), what does it take to faithfully reproduce that type of sound? I think it is contrast and articulation (and not so much of rhythm as defined as periodic beat). Yes, human voice and strings are two of my favorite instruments, so my view may be biased.Good point...you've obviously thought about this quite a bit! You may be biased, but a bias towards the human voice is probably a good thing for any speaker designer.

I love to hear what some of your favorite recordings are, both for general listening enjoyment and for subwoofer testing. For the latter, I'd particularly like to know specific things you listen for, and what they "mean" to you when evaluating/improving a product.



I need to discuss with the web designer. I may not have communicated them well with him.I think you may have similar issues in the "specifications" section...the F15 and the D15SE are listed as having the same dimensions.

millerwill
11-01-2008, 04:30 PM
I need to discuss with the web designer. I may not have communicated them well with him. I have published DS1200 and DS1500 curves before. They are almost idential below 60hz for the reason GirgleMirt mentioned. Above 60hz, the roll-off is different for 12" and 15" due to the magnitude of inductance are different in those two models. Anyway, I will correct that as soon as possible.

Thanks much for the detailed reply; much appreciated.

BTW, I presume that the 12" sub would be quite adequate for my medium small room, 2200 ct ft; is that right? I've had a SVS PB10 ISD for ~ 3 yrs and liked it, though I'm always open to something better.

Also, is the only difference between the F12 and F12SE the finish? (I actually prefer the black oak of the F12, to make it 'disappear' more easily.)

Blake1214
11-01-2008, 10:19 PM
There is a historical reason for me try to clone the frequency response. When I was designing DS15 (our first 15" driver), I had problem deciding what roll-off contouring I should use for the low end. I want it sound as close to our 12" as possible. I constantly switch between the two in my listening room.


Hi Brian,

If you guys tried to make the 15" sound as close to the 12" as possible, does this mean the 12" driver sounds better than the 15"? The 15" has more output but gives up slightly on SQ? If so, will it be correct to say we can just add more 12"s to our setup to increase output but won't be able to improve SQ with the 15". Which one of these drivers do you think will be a better setup with the Sierra 1's? (In a dual setup)

scape
11-02-2008, 04:36 AM
Hi Brian,

If you guys tried to make the 15" sound as close to the 12" as possible, does this mean the 12" driver sounds better than the 15"? The 15" has more output but gives up slightly on SQ? If so, will it be correct to say we can just add more 12"s to our setup to increase output but won't be able to improve SQ with the 15". Which one of these drivers do you think will be a better setup with the Sierra 1's? (In a dual setup)

+1 on this question, I started to get that impression from this thread. over time of research I heard forward firing was also better for music, but I think that is too subjective to the layout of the sub and quality of components.
I did stumble upon this thread (http://www.avsforum.com/avs-vb/showthread.php?p=10385439#post10385439), ironically while reading this one, which may help. but I'm sure Brian will clear this up anyway :)

RythmikAudio
11-02-2008, 07:44 AM
+1 on this question, I started to get that impression from this thread. over time of research I heard forward firing was also better for music, but I think that is too subjective to the layout of the sub and quality of components.
I did stumble upon this thread (http://www.avsforum.com/avs-vb/showthread.php?p=10385439#post10385439), ironically while reading this one, which may help. but I'm sure Brian will clear this up anyway :)

The difference in sound between 15" and 12" drivers are now less than DS15. You really have to play them in the same room and back to back to hear the difference and even then, the difference is very subtle. If you crossover at 60hz or below (the most likely scenario with Sierra-1), the difference is almost zero. I hope this will clear things up. If not, I need to explain how servo works.

Dave had both of my 15" and 12" complete subs in test boxes last year for his evaluation. He was surprised that the two frequency response are almost right on each other. That is a feature, but a mistake. Keep in mind, what is the difference between servo and nonservo? Servo has feedback connected from the sensor output and nonservo has feedback connected from the amplifier outputs. With feedback connected from amplifier output in nonservo, it can only control the amplifier output to follow a linear relation with respect to input signal. The actual speaker output still needs to go through the transformation from electrical energy to acoustic energy. With servo, we are controlling so that sensor signal is linearly proportional to the input signal, completely bypass the interface between amplifier and speaker. As a matter of fact, we can even insert a 6ohms resistor in series with the driver coil and the frequency response would still be the same. We can also change the enclosure volume to 2x as big in sealed box (the case for vented box is a bit different) and still frequency response is still very close +/-1db or less. All of these demonstrate the consistency and coherence of servo subwoofer.

The new driver DS1500 in both F15/D15 is different from DS15 (our first generation 15" driver) in that the moving mass has been reduced by 20%. I contribute that to a more dynamic sound in the new model.

I seldom disclose or explain how servo reduces distortion. And that have left a lot to imagination. I've even seen one comment that even in servo you need to have the same linearity as nonservo. My reply wa very simple: "have you written down the close form equation for distortion analysis?" As a remedy of the problem, I now want to design a PowerPoint presentation to describe how the servo and nonservo are different. As a matter of fact, the two can be compared side by side to get an apple to apple comparison through the method of equivalent circuit analysis.

For those who are versed in T/S parameters, let us now pretend we don't even know T/S parameters and think what the impedance of a bass driver is made of. It is an ideal motor (called back EMF) in series with a voice coil resistor. Let us ignore the voice coil inductance for now. The current goes through the driver and causes an IR drop (current times resistor) which is a voltage number. To keep the discussion complete, let us say the voice coil resistance is Rvc, and the current is Ivc. Back EMF is also a voltage number and it is related to BL*v. BL is also referred to as BL profile which may not be linear. The amplifier output, Vop = BL*v+Ivc*Rvc. Vop is distortion free. Let us further assume BL is perfectly linear and v is perfectly linear. Does that mean the equation is balanced now? No. If Rvc is 0 (which is type of assuming we use a superconductor), then the equation is balanced. If Rvc is not 0, there will be counter-distortion current to counteract with the nonlinearity of spider/surround, flux modulation, all sorts of distortion mechanism that has no bearing with BL linearity. That counter-distortion is still a distortion components. That components creates a nonlinear IR drop with Idist*Rvc. Now the equation is not balanced at all. Right hand side have disortion component and left hand side does not. So BL*v needs to have distortion component that is opposite sign of Idist*Rvc and that is how the velocity of cone becomes distorted even when you have perfectly linear BL profile. Yes, we have heard some manufacturers want you to believe as long as they have linear BL, then it will be the ultimate drivers. Here you hear the other side of that story. Also Rvc is voice coil resistor with a temperature coefficient of 0.3%/Celsius. As the Ivc*Rvc modulates over time, there will be additional distortion mechanism. So here is the summary for the distortion in nonservo subwoofer:
1) The distortion and hysteresis (memory effect) of spider/surround creates a Idist*Rvc component as an internal source of distortion, this source goes to affect BL*v and cause it the have distortion components and cause a new Idist value and this process iterate until the equation is balanced.
2) BL profile can cause a distortion component.
3) Voice coil resistance can modulate over time and cause a modulation distortion best described as thermal memory distortion.

So the total distortion is contribution from all 3 above.

Now how does servo's equivalent circuit compares to the above? Our servo has a unique feature of taking both velocity sensing and current sensing feedback. The result is it creates an equivalent circuit that is very similar to nonservo except a couple of "subtle differences".

1) The BL profile is replaced with the BL profile of sensing coil (not the driver coil). We have designed the sensing coil to be super overhang. It is way more linear and this does not reduce the efficiency of the speaker at all. I've seen several so-called "linear motors" widens the magnetic gap so much in order to get linear BL profile. It reduces efficiency as a side-effect and that leads to other type of distortion. Here we take a different approach. We can achieve linear BL profile while not widening the gap at all.

2) The equivalent Rvc value is almost resistive and it is only 1/3 of actual voice coil resistance. Whenever it is possible, we'd like to make equivalent Rvc as low as possible while maintain unconditional stable characteristic of the system. 1/3 is what we can achieve so far.

3) The temperature coefficient of Rvc is now 90ppm/Celsius because we use Mills MRA10 audiophile resistor as the current sensing resistor.

To complete the picture, the equivalent circuit of servo is again a back EMF (with profile from sensing coil) in series with a resistor only 1/3 of physical voice coil value and with a temperature coefficient of only 0.009%/C. Because the Rvc is now only 1/3, the distortion caused by spider/surround... is only 1/3 of nonservo and we are trying to put this number as small as possible and in the future it can be even lower. As I have mentioned before, surround/spider distortion is nonlinear memory effectdistortion. BL profile distortion is linear and coherent/consistent all the time. That 1/3x reduction addresses both types of distortions.

The physical aspect of the driver such as driver coil's BL profile and voice coil resistor are not in the equation at all. The distortion components of driver coil's BL nonlinearity is indirectly in the equation because the distortion caused by it is reduced to 1/3 because of 1/3 equivalent Rvc.

All these have contributed to improvement in sound. Another important feature of directservo is now we have 3 different Q characteristic in the system:

1) The physical Q value. Physical Q value determines the energy transfer ratio between our amps and speaker. For instance, even though 0 voice coil resistance can eliminate a lot of distortion sources, it causes an undesirable stall effect that the frequency response follows a -6db/oct starting from 100hz all the way to 5hz which is not very good at all. The best physical Q value is around 0.7 to 0.9 to ensure max energy transfer in the pass band.

2) The system Q value determined by the equivalent circuit should be as low as possible as it is proportional to "equivalent" Rvc. Currently it is 0.3 for 12" driver and 0.25 for 15" driver. Lower equivalent Rvc increases damping force. When you push the cone, you can feel a stronger resistive force pushing you back. This characteristic is best observed in free air because once you are in a box and you really need to push fast enough to emulate the frequencies above 10hz (otherwise, you will be just excercising the spring force of a sealed box). In a spring-mass-friction system, resistive force is the only one that dissipates energy (this is also how we are different accelerometer-based approach, which implements a very large spring force in the equivalent circuit, and spring force does not dissipate energy). It also means the cone would transfer less and dissipate more of the standing wave inside the enclosure. Moreover, if the system is accidentally push out of their linear operation range (such as clipping) or deviated from their linear path due to nonlearity of the system, it can recover 3x faster than nonservo as soon as it is back to linear range. The result is a sense of fast bass under almost all condition.

3) Final time domain/frequency domain Q value. Although system Q should be as low as possible as we push below 0.25, the final frequency response from the sub stay above 0.5. Anything below 0.5 can sound very lean. For this reason, we have provided three settings for everyone to try (0.5, 0.707, 1.0) and most listeners like 0.5.

Servo is the only approach that can completely decouple all three Q values without one stepping on another. Our directservo further improves on that as 1) our impedance loading component is more resistive than accelerometer-based approach, and 2) There is only two resistor and one capacitor between our sensing coil and the feedback summing point of power amplifier. It has the least coloration. So I also like to call our servo as no-catch servo technique. BTW, DirectServo means direct coupling, both electrically and mechanically.

ccotenj
11-02-2008, 08:32 AM
man, that's a lot to chew on on a sunday morning... :)

thanks brian...

buddhadas
11-02-2008, 09:18 AM
...Or any other morning for that matter. Thank God I was fortunate enough to stumble upon Ascend speakers and find speakers I like because they sound good. Knowing Dave, and how he always puts the best product out there, I can only assume that the Rythmik subs will sound equally as good. No offense Brian, but that description was just a schooch beyond me.:confused:
I do appreciate your willingness to discuss your product(s) with us here.

Peace,

Jim

RythmikAudio
11-02-2008, 09:42 AM
...Or any other morning for that matter. Thank God I was fortunate enough to stumble upon Ascend speakers and find speakers I like because they sound good. Knowing Dave, and how he always puts the best product out there, I can only assume that the Rythmik subs will sound equally as good. No offense Brian, but that description was just a schooch beyond me.:confused:
I do appreciate your willingness to discuss your product(s) with us here.

Peace,

Jim


It is ok. For non-techies, I have another version to compare nonservo vs servo. It is like compare a dumb bomb and a smart bomb. A dumb bomb can home in a target when wheather condition is good. A smart bomb constantly adjust its direction between iis current position and target position and the result is a higher hit rate in practical use.

buddhadas
11-02-2008, 09:52 AM
When I first read this, I thought you "said" dumb blonde, after re-reading that makes perfect sense to this old fart.

Thanks,

Jim

mziegler
11-02-2008, 11:11 AM
Any chance either if the 15" subs will come in honey oak?

millerwill
11-02-2008, 03:58 PM
I still educating myself wrt Rythmik subs and am confused by the 'Product selection guide' on their website. The demarkation between 'large' and 'medium' sized rooms is stated to be '115 sq ft = 35 sqm'. But 1 sqm is 10.76 sq ft, so that 35 sqm is ~377 (not 115) sq ft. My room is ~250 sq ft, so it's relevant to know whether it is 'medium' or 'large' with regard to the size of sub that is recommended. I think it is 'medium' (actually a small 'medium') so that for HT a 12" sealed sub is probably recommended. Right?

millerwill
11-02-2008, 05:53 PM
I still educating myself wrt Rythmik subs and am confused by the 'Product selection guide' on their website. The demarkation between 'large' and 'medium' sized rooms is stated to be '115 sq ft = 35 sqm'. But 1 sqm is 10.76 sq ft, so that 35 sqm is ~377 (not 115) sq ft. My room is ~250 sq ft, so it's relevant to know whether it is 'medium' or 'large' with regard to the size of sub that is recommended. I think it is 'medium' (actually a small 'medium') so that for HT a 12" sealed sub is probably recommended. Right?

I think I see the error on the website: 1 m = 3.28 ft, and 3.28*35 = 115.

Somebody forgot to square 3.28 in converting SQUARE meters to SQUARE feet. I presume that the division between 'medium' and 'large' rooms is 35 sqm = 377 sq ft.

And wouldn't the VOUME of the room be more useful a measure than the floor space? I.e., doesn't height matter?

RythmikAudio
11-02-2008, 06:21 PM
I think I see the error on the website: 1 m = 3.28 ft, and 3.28*35 = 115.

Somebody forgot to square 3.28 in converting SQUARE meters to SQUARE feet. I presume that the division between 'medium' and 'large' rooms is 35 sqm = 377 sq ft.

And wouldn't the VOUME of the room be more useful a measure than the floor space? I.e., doesn't height matter?

I have made a correction. I do have a dedicated 300 ft^2 room with 9 ft ceiling and that should be a medium size room. Height would matter, but not in a linear relation.

I also corrected the frequency response and temporaory copied the plots from DS1500 to 15" subwoofers. As far as I know, all frequency response plots are now correct.

F15 currently only offers two finishes: black oak and walnut. I didn't consider any light color option as we want to use darker color to make it look smaller :rolleyes:

millerwill
11-02-2008, 06:48 PM
I have made a correction. I do have a dedicated 300 ft^2 room with 9 ft ceiling and that should be a medium size room. Height would matter, but not in a linear relation.

I also corrected the frequency response and temporaory copied the plots from DS1500 to 15" subwoofers. As far as I know, all frequency response plots are now correct.

F15 currently only offers two finishes: black oak and walnut. I didn't consider at light color option as we want to use darker color to make it look smaller :rolleyes:

Thanks much, Brian. My 250 sq ft room is thus medium/small, so it 'sounds' like the F12 would be the sub I would be interested in. (And I LIKE the black oak cabinet the best!)

As I gather from the website, you only produce 'complete' subs that are sealed; i.e., you don't produce ported ('vented') versions of your subs (though a person could do one DIY). Is that correct?

RythmikAudio
11-02-2008, 06:54 PM
I love to hear what some of your favorite recordings are, both for general listening enjoyment and for subwoofer testing. For the latter, I'd particularly like to know specific things you listen for, and what they "mean" to you when evaluating/improving a product.


Some of my favorite CD:
Eagles: hell freeze over (XRCD)
Dire Straits: Making Movies
Edgar Meyer et al: Heatland an Appalachian Anthology
Rosinni: String Sonata 1-6 (XRCD)
Jazz at the Pawnshop
Massenet: Ballet Music (Klavier)

I also use these to test subwoofer integration. The sound I am looking for is a perfect integration between front speakers and subwoofer so that the whole system sounds like a single fulll range system. One does not need to play a bass heavy music to appreciate the value of subwoofer. A subwoofer adds to all 3 dimensions of the sound stage. It gives a more complete boundary of instructment without making it fat. It is almost as if you can hear more detail of the sound. IMHO, it is the low frequencies signal that connects one note to next which makes the music flow with specific effects. Even instruments like solo violin is often played with techniques try to add low frequency contents to the sound to make it sound more rhythmic.


The CDs that I test subwoofers for bass response include Massenet, flight of the cosmic Hippo (Bela Fleck), U571 (the depth charge dropped in the water and the explosion), and more recently Blue Man's group, Peom of Chinese Drums. BTW, I also enjoy Chesky demo CD2. in particular the track with a small percussion band circling around the microphones. With a good system (with or without a subwoofer), you can clearly hear the group circling our speakers going to the behind of speakers, then to the right of the right speaker, then to the front of the speakers (ie, between speakers and me), and then go to the left of lef speaker, then go behind the speakers again, then go on and on. All 4 instruments are clearly distinguishable and circle with distance between them. Another track of the CD tests the image height in your sound system. These tracks remind me that 2 channel audio is not dead, we just haven't exploited its full potential.

RythmikAudio
11-02-2008, 06:58 PM
Thanks much, Brian. My 250 sq ft room is thus medium/small, so it 'sounds' like the F12 would be the sub I would be interested in. (And I LIKE the black oak cabinet the best!)

As I gather from the website, you only produce 'complete' subs that are sealed; i.e., you don't produce ported ('vented') versions of your subs (though a person could do one DIY). Is that correct?

Vented version is in the work. We would like to put in a couple of new features before we ship them. They will be all 15" based. I don't recommend 12" for vented subwoofer anymore.

millerwill
11-02-2008, 07:05 PM
Vented version is in the work. We would like to put in a couple of new features before we ship them. They will be all 15" based. I don't recommend 12" for vented subwoofer anymore.

VERY interesting! Thanks again.

jedi.night
11-04-2008, 12:03 PM
Well count me In!

I placed an order for a Pair of RYTHMIK D-15 SE 15.

These will replace my SVS PC12 Ultra in my HT.

Had the upgrade bug and wanted to try out a sealed sub that hits hard and low.

Was a tough decision as I was also considering the HSU ULS-15, and the SVS PB13ultra.

I ruled out the ULS-15 because of the price (really wanted a pair and was just too much)

I ruled out the PB13Ultra, mainly because of it's size and weight, it would have be tough for me to place it in an optimal position in my room.

My HT family room is about 432 sq feet or 3500 cubic feet, but is basically a rectangular room with 2 doors that close. I cut the room in half long ways for the HT part, So Its much smaller than the footage would indicate.
I'm also running an HSU MBM-12 in my setup and will also use it with the 2 rythmiks.

Hopefully they won't disappoint!

Now if Dave can just ship them fast enough for me to get them by the weekend!

DougMac
11-04-2008, 12:17 PM
Well count me In!

I placed an order for a Pair of RYTHMIK D-15 SE 15.

Be sure to give us a review once you've got them set up and dialed in!

Doug

curtis
11-04-2008, 12:22 PM
I'm also running an HSU MBM-12 in my setup and will also use it with the 2 rythmiks.
Try them with and without the MBM. I would also contact Hsu about changing that MBM to a sealed unit.

Blake1214
11-04-2008, 01:23 PM
Well count me In!

I placed an order for a Pair of RYTHMIK D-15 SE 15.

These will replace my SVS PC12 Ultra in my HT.

Had the upgrade bug and wanted to try out a sealed sub that hits hard and low.

Was a tough decision as I was also considering the HSU ULS-15, and the SVS PB13ultra.

I ruled out the ULS-15 because of the price (really wanted a pair and was just too much)

I ruled out the PB13Ultra, mainly because of it's size and weight, it would have be tough for me to place it in an optimal position in my room.

My HT family room is about 432 sq feet or 3500 cubic feet, but is basically a rectangular room with 2 doors that close. I cut the room in half long ways for the HT part, So Its much smaller than the footage would indicate.
I'm also running an HSU MBM-12 in my setup and will also use it with the 2 rythmiks.

Hopefully they won't disappoint!

Now if Dave can just ship them fast enough for me to get them by the weekend!


Looks like we had the same subs in mind. I almost pre-rdered the PB13 but I really wanted to concentrate on SQ. Although I'm sure the PB13 would outperform my PC plus in both output as well as SQ, I decided to look elsewhere that was really about SQ. I knew I can retain ouput by just adding another sub.

When the ULS-15s came out, I was almost sure I would be ending up with a pair. At the same time, I really wanted to wait for what Dave was going to offer. I'm guessing the ULS-15 and the D-15 are more comparable. Price wise, I think they're also in the same league (after dual discount and pretty much the same if you go quads). It would definitely make the decision easier if the Rythmiks were at their original price or have discounts on multiples. Unless there's something different in the components used from when they were selling directly from Rythmiks' website, doesn't it kind of contradict with the whole Internet Direct model? This is in no way an attempt to cause any type of controversy. But just something that l thought about when considering for these subs. I may be totally wrong though if there were indeed changes or improvements on these subs.

Please let us now how they work out for you!!

Blake1214
11-04-2008, 01:27 PM
Try them with and without the MBM. I would also contact Hsu about changing that MBM to a sealed unit.

I had no idea a sealed unit was an option for the MBM. Is this custom or a new unit they're offering?

BradJudy
11-07-2008, 12:57 PM
I'm glad to see a new subwoofer partnership in place. The Rythmik products have an excellent reputation.

Having bamboo Sierra's, I would like to see a bamboo option, and I've posted my thoughts in the other thread.

jedi.night
11-08-2008, 04:56 AM
Curtis, Dave, anyone,

I should be receiving the pair of 15 inch SE's on Monday.

Questions for all, since after research there is some conflicting ideas on calibration of 2 co located subs.

In my setup, I will most likely have them both co located center stage under my plasma TV.
Since they are identical subs, most likely they will be able to be set at identical gains to achieve calibration with my mains at 75 dbs.
However using a RS meter do I calibrate them individually at 75 dbs with one on and 1 off, and then leave them both on boosted by co location? or do I then back down the sub trim to 75 db's once they are both on together?

I will also be using audyessy with my Denon 2809, but at least I can compare and contrast easily once I get them set up, but turning it on or off.

millerwill
11-08-2008, 05:49 AM
Curtis, Dave, anyone,

I should be receiving the pair of 15 inch SE's on Monday.

BTW, what is the size of your room? (Thanks!)

RythmikAudio
11-08-2008, 06:22 AM
If you don't have a computer program to do this for you, I will use the following manual process. If you are using Sierra-1 or 340SE, please also let me know and I can come up with a initial setup to start with.

You will need: 1) a calibration CD. The one I use is Stereophile test CD 2, 2) SPL meter and a tripot, and 3) paper printout from spreadsheet.

Go through the measurement in the following steps (this applies to all brands):

1) Do the close mic measurement (placing the mic very close to cone in 2") on subwoofer (open up the xover point).

1a) For sealed front, do the same thing. Vented front speakers are a bit more complex as it needs to sum the output from woofer and vent. Since vent opening and woofer size is a bit different, we cannot directly add them together. However, the reading from the vent can help us determine what tuning frequency is for the front. The interesting point for vent speakers is the phase shift is 180 degrees at tuning point. For sealed box, the corner frequency point (-1db or -3db) has a phase shift of 90 degrees. This will help determine the phase adjustment we need to do. As it will be up to 90degrees difference between these two cases.

2) Do the far field measurement of subwoofer by placing SPL on tripod at your lisenting height and location.

3) Do the same for the front speaker.

4) Now do the same for both front speaker and subwoofer on.

The comparison of 1) and 2) gives you idea about the room mode you may have. The sub should have pretty flat response in close-mic measurement 1) from 10hz (-4db) to 80hz. So any big up and down in 2) is due to room modes. Try subwoofer at different location and write down their numbers for step 2) and 4) so that you can do a selection. The comparison of 2), 3) and 4) will give us idea if the xover point is good.

For vented front speakers, one needs to add phase lead the subwoofer (EDIT: I made a mistake in the original post) to compensate for the extra phase shift of vented fronts using HT receiver's speaker distance menu. Put the subwoofer farther away than what it actually is relative to front speakers can fool the receiver to pull the timing of subwoofer ahead, which is equivalent to a phase lead. In other words, to compensate for the additional phase shift for front speakers (vented in particular), we need to add phase lead (or pull timing ahead) on subwoofer to get perfect phase alignment between fronts and sub(s) when the xover point and the tuning frequency of vent front is too close. The difference between the xover set in the receiver and vent's tuning frequency determines how much of that 90 degress shift is actually affecting your setup. (Keep in mind, all HT receiver uses LR alignment design and put a 2nd order filtering on front speaker and 4th order filtering on sub, the assumption for them to do that is that at xover point the front speaker will have 90 degrees phase shift. As one can see, this assumption applies to sealed more than vented. But that doesn't mean it will not work for vented fronts. We just need to know how to adapt).

If you don't use a HT receiver, you need to be able to xover the vent front speaker higher enough than the tuning frequency (sealed box is ok). Otherwise, the best bet is to run front speaker full range. This is particularly true for those with 5" woofer in vent configuration. For sierra-1 and 340SE, if you do full range, the xover setup you want to use on plate amp is set the low pass switch to 50hz/24 and delay control at 10 o'clock position and gradually adjust the xover knob from 80hz to 50hz to see the integration result in step 4).

Please feel free to ask questions. I will put all the essential information on a integration guide.

jedi.night
11-08-2008, 06:59 AM
BTW, what is the size of your room? (Thanks!)

It's about 3500 cubic feet, rectangular room. But it's deceiving because I cut the room in half long ways for the HT setup.

36 ft length X 12 feet Wide X 8 feet height. is the Total room space.

However I use about a 12 X 12 section of the room turned on its side for the HT. 2 doors but I keep them closed.

jedi.night
11-08-2008, 08:08 PM
Anyone,
can you explain to me how the damping factor and rumble filter work exactly.
I believe the rumble filter is just another term for high pass filter, correct? But I'm not sure how those settings relate to damping.

My D-15 SE's will be used primarily for HT and Gaming. What settings would theoretically benefit me the most?

curtis
11-08-2008, 10:39 PM
Anyone,
can you explain to me how the damping factor and rumble filter work exactly.
I believe the rumble filter is just another term for high pass filter, correct? But I'm not sure how those settings relate to damping.

I think the Rythmik site has some good information.

The differences in damping settings were pretty noticeable to me. I use high damping and 14hz. Play around with the settings to see what you like best. There is no right or wrong here.

RythmikAudio
11-09-2008, 05:30 AM
I think the Rythmik site has some good information.

The differences in damping settings were pretty noticeable to me. I use high damping and 14hz. Play around with the settings to see what you like best. There is no right or wrong here.

Curtis is correct. We have both rumble filter and extension filter. But we shouldn't confuse the two. First, extension "filter". Even though we call it "filter", it is not any loss of signal when compared to conventional sealed subwoofers. Servo subwoofers, when used without extension filter, can extend down to 5hz. But that has little practical use. So we put in a 2nd order HP filter to match a normal sealed subwoofers. Since I have to put one in anyway, I also notice all sealed subs they have slightly different corner frequency and different damping characteristic, wouldn't it better to put in one offering some versatility? So I come up with 3 frequency and 3 damping setting for a combination of 9. In practice I found them to be very useful too. My favorite is high damping (in all music, movies, and games). It gives the least ringing of the 3 damping settings (and in theory it should have no ringing at all). It also gives an edge in terms of clarity because of lack of ringing. You will notice that in all music contents, even in synthesized music such as game. As more and more customers get their hands on the servo subwoofers, they can compare notes. The low damping has the largest ringing, but it has steeper roll-off. This type of roll-off contouring combined with higher corner frequency has been used by early minimonitors such as L/S 3/5A. The advantage is that it is able to play louder (only when you set it at 28hz) as compared to 14hz high damping.

Rumble filter is different. It is a third order extra filter for those still use Vinyl, or those movies with too much subsonic content and therefore overloads the amplifier. It has only on and off position. The roll-off frequency is 20hz.

jedi.night
11-09-2008, 06:43 AM
I think the Rythmik site has some good information.

The differences in damping settings were pretty noticeable to me. I use high damping and 14hz. Play around with the settings to see what you like best. There is no right or wrong here.

Thanks curtis,
Is your setup primarily for Movies or Music?

curtis
11-09-2008, 07:01 AM
Thanks curtis,
Is your setup primarily for Movies or Music?
Both!

RythmikAudio
11-12-2008, 06:50 AM
I am booked for a trip for whole next week. There will be no subwoofers shipped from us or Ascend. Please patiently wait for me come back to work on Nov 24.

RythmikAudio
11-13-2008, 05:17 AM
I am booked for a trip for whole next week. There will be no subwoofers shipped from us or Ascend. Please patiently wait for me come back to work on Nov 24.

I have uploaded a page explaining phase alignment and its importance. http://www.rythmikaudio.com/phase1.html

The short version of it is that if one uses an HT receiver and its bass management for subwoofer and set the vented front spekaers to small, one needs to put the distance of subwoofer 4 ft farther than what it actually is (compared to the front speakers) so that it fools the receiver to put in a phase lead to the subwoofer to compensate for the extra of vented front speakers as compared to sealed front speakers. 4 ft is for 5" woofer in the front speakers. For 7" woofer in vented front speakers, I would recommend 2 ft as a ball part number to start with. For sealed front speakers, one can try just 1 or 2 ft farther to see if it improves the integraton (by filling up the mid bass sound).

Jonnyozero3
11-13-2008, 03:23 PM
Interesting...do you think that any of the Auto setup routines like MCACC, Audyssey, EZset/EQ, YPAO, etc compensate for this? My AVR (HK AVR435) has always set my sub at a far greater distance than it is (chooses like 10ft when the sub is ~3ft away).

scape
11-14-2008, 04:53 AM
Interesting...do you think that any of the Auto setup routines like MCACC, Audyssey, EZset/EQ, YPAO, etc compensate for this? My AVR (HK AVR435) has always set my sub at a far greater distance than it is (chooses like 10ft when the sub is ~3ft away).

my denon put it mine at 16ft, when it's at 10ft from listener. after reading brian's comment, that makes sense now. however, I'm not sure how far these calibrations actually go, where as professional setup might still enhance things.

RythmikAudio
11-14-2008, 05:40 AM
Well I don't know how robust the EQ algorithm is. I deal with software that affects millions of dollars of design works every day. In that case, there is always a verification step that uses an independent type of algorithm to verify the design work. That can catch a lot of problems such as software not able to handle certain combination of data, errors in the software... etc. Unfortunately, in EQ, you don't get that. Therefore common sense is very important. If you xover at 80hz and that is a wavelength of 12ft. So any program puts a 6 ft extra is literally inverting the phase on the sub. What I would do is I will wire the subwoofer output of phase (if there is a switch on the plate amp) and now see the results from the program. If the algorithm performs consistently, it should now remove that 6 ft distance. If not, then the problem it tries to resolve is not phase problem.

EDIT: another issue is digital latency. This applies to all digital process not symmetrically applied to all channels. My Denon 4802 has a very bad latency (defined as the delay between signal in and signal out) on subwoofer channcel as compared to other channels when I use analog mode. The reason is in their design, there is no analog domain filtering on sub. It is all done in digital domain. So it needs to convert analog to digital, then digital filtering, then digital to analog, not to mention a couple of cycles to do digital FIFO bufferring to avoid overrun errors. SO it is possible that the distance is for this. BTW, the sampling rate for subwoofer is not same as the one for front channels.

Another point is, the plots I give you are all based on close-mic measurement with the least amount of interference. When you place mic at listening position, the room mode will blur phase information and making it more difficult to extract the exact phase relation. In my view, a close-mic measurements should be very important part of EQ calibration process. With that as reference, the program would know how much is contributed to subwoofers itself, and how much is to the room. These two should be handled differently.

On a different subject, I would like to say EQ and servo IS complimentary. I one time asked the designer of Audyssey about how his program impacts the basic quality of the speaker system itself. I didn't get an answer. We all know the answer. If we think of audio components such as pre-amp, power-amp, speaker as individual components in a chain and EQ is part of it, these components cannot correct the mistake/error/distortion made by other components as there is no close loop to feedback the error back to EQ in real time. One example is, if we have a ringing in the woofer at 1000hz, one may say we just EQ it out. However, most people forget that the distortion in speaker is generated at the very last stage of this chain. EQ can control the signal passing through it, but it cannot control the distortion happen at the end of the chain. For those who reads distortion plots all the time would know, if we have a 1000hz ringing, we would get a bump in 2nd order distortion number at 500hz (because 500x2=1000), and a bump in 3rd order distortion number at 333hz (333x3=1000). The problem is still there. EQ solves part of the problem. I also think making the frequency response as perfect as possible (such as getting a very flat close-mic response from speakers and good speaker location) can make EQ algorithm easier to find an optimal solution.

Gov
11-14-2008, 05:46 AM
I have owned two Pioneer receivers and everytime I have run MCACC, it sets my sub almost exactly the same everytime and almost the exact distance to my listening position as well

RythmikAudio
11-14-2008, 06:04 AM
I have owned two Pioneer receivers and everytime I have run MCACC, it sets my sub almost exactly the same everytime and almost the exact distance to my listening position as well

This is not related to your situation but again just demonstrate the importance of verification. My officemate in graduate school wrote a program verifying two logic designs are same in terms of functionality. At the end of the program, it prints out "verified". The advisor joked along the line that how does he know the program does more than just printing out "verified" because the program was complete quiet in printing out message. Of course, we know better than that. In addition, it is very easy to verify if it does what is supposed to do. Move the location, flip the phase switch... Throw in something that you know will change the results. (Oops I am in trouble now :-))

Gov
11-14-2008, 08:42 AM
Can someone confirm the actual dimensions of the F-15 sub for me? Is it correctly stated on the Ascend website?

Thanx

curtis
11-14-2008, 09:50 AM
Can someone confirm the actual dimensions of the F-15 sub for me? Is it correctly stated on the Ascend website?

Yup...it is correct.

Gov
11-14-2008, 10:19 AM
Thanks!

lokimydog
11-14-2008, 10:24 AM
Are there plans on making an F15SE in piano black that this front firing? Could this be consider a special order item if I wanted it now? I'm within days of possibly going with a pair of ULS-15 but would reconsider since this option might save me a few hundred dollars. Anyone live locally that wouldn't mind demoing the sub for 15 minutes. Im in Gardena btw.

curtis
11-14-2008, 11:55 AM
Are there plans on making an F15SE in piano black that this front firing? Could this be consider a special order item if I wanted it now? I'm within days of possibly going with a pair of ULS-15 but would reconsider since this option might save me a few hundred dollars. Anyone live locally that wouldn't mind demoing the sub for 15 minutes. Im in Gardena btw.
Come on over! Send me a PM and we can set something up.

jedi.night
11-14-2008, 12:45 PM
Well I don't know how robust the EQ algorithm is. I deal with software that affects millions of dollars of design works every day. In that case, there is always a verification step that uses an independent type of algorithm to verify the design work. That can catch a lot of problems such as software not able to handle certain combination of data, errors in the software... etc. Unfortunately, in EQ, you don't get that. Therefore common sense is very important. If you xover at 80hz and that is a wavelength of 12ft. So any program puts a 6 ft extra is literally inverting the phase on the sub. What I would do is I will wire the subwoofer output of phase (if there is a switch on the plate amp) and now see the results from the program. If the algorithm performs consistently, it should now remove that 6 ft distance. If not, then the problem it tries to resolve is not phase problem.

EDIT: another issue is digital latency. This applies to all digital process not symmetrically applied to all channels. My Denon 4802 has a very bad latency (defined as the delay between signal in and signal out) on subwoofer channcel as compared to other channels when I use analog mode. The reason is in their design, there is no analog domain filtering on sub. It is all done in digital domain. So it needs to convert analog to digital, then digital filtering, then digital to analog, not to mention a couple of cycles to do digital FIFO bufferring to avoid overrun errors. SO it is possible that the distance is for this. BTW, the sampling rate for subwoofer is not same as the one for front channels.

Another point is, the plots I give you are all based on close-mic measurement with the least amount of interference. When you place mic at listening position, the room mode will blur phase information and making it more difficult to extract the exact phase relation. In my view, a close-mic measurements should be very important part of EQ calibration process. With that as reference, the program would know how much is contributed to subwoofers itself, and how much is to the room. These two should be handled differently.

On a different subject, I would like to say EQ and servo IS complimentary. I one time asked the designer of Audyssey about how his program impacts the basic quality of the speaker system itself. I didn't get an answer. We all know the answer. If we think of audio components such as pre-amp, power-amp, speaker as individual components in a chain and EQ is part of it, these components cannot correct the mistake/error/distortion made by other components as there is no close loop to feedback the error back to EQ in real time. One example is, if we have a ringing in the woofer at 1000hz, one may say we just EQ it out. However, most people forget that the distortion in speaker is generated at the very last stage of this chain. EQ can control the signal passing through it, but it cannot control the distortion happen at the end of the chain. For those who reads distortion plots all the time would know, if we have a 1000hz ringing, we would get a bump in 2nd order distortion number at 500hz (because 500x2=1000), and a bump in 3rd order distortion number at 333hz (333x3=1000). The problem is still there. EQ solves part of the problem. I also think making the frequency response as perfect as possible (such as getting a very flat close-mic response from speakers and good speaker location) can make EQ algorithm easier to find an optimal solution.

In my recent experience with a fresh pair of 15 inch SE's that I got on monday from Ascend, Audyessy works even better. Compared to my Previous setup of a PC ultra and MBM-12, the new setup coupled with audyessy is nearly flat from 13 hz to around 90hz. (or at least a much flatter curve then with audyessy and other setup).
Some feel over on the AVS forums believe Audyssey works great to begin with but even better with sealed subs for HT. In my experience this is true.
Even with the 2 SE's not co located, my Frq response was not very good (probably do to my room setup), but Audyessy performed like magic on both subs (seen as one). I also must say that the new Dynamic EQ feature is excellent coupled with the Rythmiks for those that don't listen at reference levels.
These Rythmik's with Audyessy are a very very nice match, IMO. I have no need for an Anti-mode SMS-1 now.

dallas
11-14-2008, 12:51 PM
for those in the thread using the SVS ultra subs, what "tuning" mode were you using? Sealed? Wide open? 10, 15 hz?

jedi.night
11-14-2008, 02:51 PM
for those in the thread using the SVS ultra subs, what "tuning" mode were you using? Sealed? Wide open? 10, 15 hz?

PC12 Ultra, in Full output 20 hz mode. No ports plugged.

RythmikAudio
11-14-2008, 05:37 PM
In my recent experience with a fresh pair of 15 inch SE's that I got on monday from Ascend, Audyessy works even better.

I was not trying to shoot down any EQ algorithm in my previous email. I was saying if the EQ came back with more delay offset than what is deemed reasonable, then we may want to try something different (for instance, different location, or xover point to get rid of sub-optimal solution from EQ algorithm). One thing is for sure, if the algorithm is presented with a simpler problem, it would definitively work better. Nevertheless, one of the got-ya with EQ that works only on subwoofer is the additional latency it introduces. It manifests as delay, or phase shift. What is worse is the phase shift from pure time delay does not top out like analog filter.

jedi.night
11-14-2008, 08:43 PM
I was not trying to shoot down any EQ algorithm in my previous email. I was saying if the EQ came back with more delay offset than what is deemed reasonable, then we may want to try something different (for instance, different location, or xover point to get rid of sub-optimal solution from EQ algorithm). One thing is for sure, if the algorithm is presented with a simpler problem, it would definitively work better. Nevertheless, one of the catch-ya with EQ that works only on subwoofer is the additional latency it introduces. It manifests as delay, or phase shift. What is worse is the phase shift from pure time delay does not top out like analog filter.


I didn't think you were, I just wanted to mention that how well it worked in my particular setup with your subs. I found it to be very beneficial. Hopefully others that have Audyessy setups will take a further look at these rythmik subs.
They seem to pair well together!

jedi.night
11-21-2008, 10:11 PM
I see the FRQ response is +- 2db's from 14-100hz but how high does the 15 inch SE actually go?

Curious because audyessy recommends my center channel be crossed at 120hz.

davef
11-22-2008, 04:50 PM
I see the FRQ response is +- 2db's from 14-100hz but how high does the 15 inch SE actually go?

Curious because audyessy recommends my center channel be crossed at 120hz.

I believe the 15" is about 2-3 dB down at 100Hz. However, I would not recommend a 120Hz crossover point for your center, even if this is what Audyssey is recommending.

muzz
11-22-2008, 04:58 PM
Do you have a 3" speaker in your center channel?
One of those satellite jobs?
If not, I don't care what Audessey suggests, that is pathetic.
If your running a Sierra center, pick 60 or 80, if a 170 pick 80, if a 340 probably 80 as well.......

120 for the CC..... LMAO

jedi.night
11-22-2008, 06:02 PM
Actually my center channel speaker is an nhtsc3, center Of the sb3 line. Rated down to 55 hz if I recall. So no it's not an htib speaker. Anyway, conflicting opinions on this as chris (audyssey developer) recommend doing what audyssey sets after calibration. It rates my mains me set at 40 us crossover! Weird that the center is getting such a high crossover setting.

muzz
11-22-2008, 06:49 PM
All I know is 120 Center HZ, especially for a center that is rated <60 is PATHETIC.
I would NEVER listen to IDIOCY like that in my life, if anyone ever told me that I would ask for their resignation IMMEDIATELY!!

Tell Chris that he has a problem, and that he needs help.

End of story.

This is one of the unbelievable suggestions I have ever heard.........
Corkey comes to mind.......

muzz
11-22-2008, 07:00 PM
I'd probably set that CC at 80

scape
11-23-2008, 07:17 AM
maybe it is the placement and room affecting the sound too much?
out of curiosity, maybe perform a round 1 calibration with the mic very close to the speaker (within 2ft), maybe even remove it from the location and see if there is a difference. audyssey rated my cener at 250hz, though it was a minisat, once i replaced the center with a 340, it now gets ranked at 80hz, I think 60hz actually but i wanted it to match my 170's @ their recommended 80hz that audyssey provided. when I initially placed my 340c below my tv, it was less than optimal (half the sound probably was getting reflected off the coffee table and carpet); once i moved it up above the tv the sound is much wider and resulting in better matched imaging with the mains, though I still find it a tad off. in all of that, the hz went from a recommended 80hz to 60hz just by moving it above the tv onto brackets. so, maybe for you position may help; out of curiosity where is it placed?

jedi.night
11-24-2008, 04:47 AM
maybe it is the placement and room affecting the sound too much?
out of curiosity, maybe perform a round 1 calibration with the mic very close to the speaker (within 2ft), maybe even remove it from the location and see if there is a difference. audyssey rated my cener at 250hz, though it was a minisat, once i replaced the center with a 340, it now gets ranked at 80hz, I think 60hz actually but i wanted it to match my 170's @ their recommended 80hz that audyssey provided. when I initially placed my 340c below my tv, it was less than optimal (half the sound probably was getting reflected off the coffee table and carpet); once i moved it up above the tv the sound is much wider and resulting in better matched imaging with the mains, though I still find it a tad off. in all of that, the hz went from a recommended 80hz to 60hz just by moving it above the tv onto brackets. so, maybe for you position may help; out of curiosity where is it placed?

Thanks for the ideas,
Mine is place above the TV on a shelf that fits the speaker perfectly. However the center speaker is about 2 feet higher than the mains.
So maybe the mic is position too low to correctly pick up my center channel response.
I will try what you said and move the mic close to it just to see what happens.
Maybe I can also angle the center channel downwards?