Page 3 of 6 FirstFirst 123456 LastLast
Results 21 to 30 of 53

Thread: Rythmik Audio 18s

  1. #21
    Join Date
    Feb 2016
    Posts
    457

    Default Re: Rythmik Audio 18s

    Quote Originally Posted by Blutarsky View Post
    The new SVS 16'ers have a 1500W amp. I wonder how this power will translate into sound compared to Rythmik? the sealed box model is only 19.5" wide... DSP vs. accelerometer? I wish I had a bunch of new subs in my room to play with. Affordable high value audio is getting better every day.
    A servo sub is managing the backwave radiation inside the box to heavily reduce it, other subs can't do that, or just have overbuilt boxes to manage it. It means that the signal the servo sub produces will be more accurate. Normal subs need a bigger amp to deal with the deleterious effects that they can't manage. Also, Rythmik subs are direct servo, so they don't use an accelerometer, they use a sensing coil that is in the same magnet gap as the voice coil. The sensing coil sends feedback to the amp and corrects the signal being sent to the woofer. The result is a much more accurate signal.

    This is why I don't understand why more companies don't implement a direct servo design. It must just be difficult to do correctly, or they just want to market giant amps and boxes, because people like big amps and big boxes, especially ones that shake a lot. It's probably more of the latter and some of the former. I mean my Dad put floor shakers in his theater as well as having a big rumbly sub. It was too much for me. I prefer accuracy and gut punching depths of rock solid sub 20 Hz bass that Rythmik subs provide. When I first heard that kind of bass from my dual F12's, it scared the hell out of me and I was immediately thrilled as my heart instantly sank because my neighbors must have been freaked out. I was immediately addicted.

    Quote Originally Posted by davef View Post
    DSP is not comparable to servo. DSP is one method (actually, a lesser expensive method these days) for equalizing / contouring the subwoofer's response as opposed to equalizing by analog means. It means the LFE signal that is being sent to the sub is once again converted to digital - then various filters are applied to the digital signal, and then it is once again converted to analog so it can be amplified and then sent to the woofer.

    Regardless of how good the DAC's are - each time an analog signal is converted to digital and then back again, information is lost.

    Servo is a real time solution whereby the woofer sends a continuous signal back to the amplifier, so that the amplifier makes sure the woofer is properly tracking the signal being sent to it.

    DSP does not have any effect on overall sound quality other than adding additional features and a simpler way of implementing eq. In fact, because of the additional A/D D/A conversions, it has a negative effect on the purity of the original signal being sent. These days, there are way to many A/D D/A conversions taking place in the audio chain. DSP in a sub would be more beneficial if the LFE output itself were digital.

    I'll take servo any day of the week when it comes to sound quality in a subwoofer.
    I love this post. This is true audiophile engineering here. Keep the signal pure and do as much as you can to keep it that way at every step. This is why I love my Schiit Bifrost Multibit so much. It stays out of the way of the music. It's so accurate, I constantly notice new things. I'm listening to Wedding Nails by Porcupine Tree again and I never really noticed how much ambient keyboard there is in the background before. You can't discover new and incredible details in music you've listened to for years on a system that is constantly screwing with the signal you send it.
    Last edited by sludgeogre; 10-07-2016 at 10:20 PM.
    -Alex
    PS4/Nvidia Shield --> Emotiva XMC-1 --> Emotiva XPA-5 --> Ascend Acoustics Sierra Towers and Horizon Center w/ RAAL tweeters (L/C/R), HTM-200 SE (Surrounds), 2x Rythmik F12 subwoofers

  2. #22
    Join Date
    Apr 2014
    Posts
    303

    Default Re: Rythmik Audio 18s

    Quote Originally Posted by davef View Post
    DSP is not comparable to servo. DSP is one method (actually, a lesser expensive method these days) for equalizing / contouring the subwoofer's response as opposed to equalizing by analog means. It means the LFE signal that is being sent to the sub is once again converted to digital - then various filters are applied to the digital signal, and then it is once again converted to analog so it can be amplified and then sent to the woofer.

    Regardless of how good the DAC's are - each time an analog signal is converted to digital and then back again, information is lost.

    Servo is a real time solution whereby the woofer sends a continuous signal back to the amplifier, so that the amplifier makes sure the woofer is properly tracking the signal being sent to it.

    DSP does not have any effect on overall sound quality other than adding additional features and a simpler way of implementing eq. In fact, because of the additional A/D D/A conversions, it has a negative effect on the purity of the original signal being sent. These days, there are way to many A/D D/A conversions taking place in the audio chain. DSP in a sub would be more beneficial if the LFE output itself were digital.

    I'll take servo any day of the week when it comes to sound quality in a subwoofer.
    That is a really helpful explanaintion of the differences! This is really simple to understand as well. I do have a follow up question though. Filtering the analog signal in real time sounds kind of tricky. Is it kind of like just a sophisticated graphic equalizer boosting or cutting frequencies that differ from when the true signal is supposed to be (where this difference is measured in the accelerometer)?

  3. #23
    Join Date
    Aug 2003
    Location
    Manhattan Beach, California
    Posts
    6,278

    Default Re: Rythmik Audio 18s

    Quote Originally Posted by N Boros View Post
    That is a really helpful explanaintion of the differences! This is really simple to understand as well. I do have a follow up question though. Filtering the analog signal in real time sounds kind of tricky. Is it kind of like just a sophisticated graphic equalizer boosting or cutting frequencies that differ from when the true signal is supposed to be (where this difference is measured in the accelerometer)?
    I can't explain it like Dave, but servo control is not a filter in the same sense as an EQ. It tracks the position of the woofer vs the output of the amplifier. It corrects in real time rather than preset filters....so it can handle anomalies such as the environment, memory, etc. On top of what the servo does, you can apply traditional EQ to it...as evidence of the parametric EQ on the amp.

    and as sludge said, the Rythmiks use a sensing coil, not an accelerometer.
    Last edited by curtis; 10-08-2016 at 11:44 AM.
    -curtis

  4. #24
    Join Date
    Aug 2003
    Location
    Manhattan Beach, California
    Posts
    6,278

    Default Re: Rythmik Audio 18s

    Quote Originally Posted by sludgeogre View Post
    I love this post. This is true audiophile engineering here. Keep the signal pure and do as much as you can to keep it that way at every step.
    I believe this is why Dave spends so much time on getting the drivers in his speakers "right". Doing this means there is less interference needed by the crossover.
    -curtis

  5. #25
    Join Date
    May 2007
    Location
    Stouffville,Ont..
    Posts
    280

    Default Re: Rythmik Audio 18s

    Quote Originally Posted by curtis View Post
    I believe this is why Dave spends so much time on getting the drivers in his speakers "right". Doing this means there is less interference needed by the crossover.
    Having control of the driver design from the ground up is what makes Rythmik, Funk, JTR, Seaton and Svs for that matter so unique. Dave relationship with his OEM is likely unparalleled...geting the right driver for the given task helps eliminate some of the added processing to reach the desired results.

    Most of the DIY community don't have this available to them and why off the shelf parts need plenty of tweaking but if done right can be made to sound just as good.

    Not trying to play devil's advocate here but I can guarantee you any sub from the Seaton, JTR or Funk will sound great with or without a servo.... JMO.
    Last edited by billy p; 10-08-2016 at 12:31 PM.
    Speakers: Towers & Horizon(w RAAL), HTM200 SE finished in espresso satin
    Sub: Funk Audio 18 in Santos

    Source: Anthem MRX 300, Oppo BDP 103D
    Apple TV, Giga 1800, & Panny 54"

  6. #26
    Join Date
    Oct 2008
    Posts
    101

    Default Re: Rythmik Audio 18s

    If you imagine all drivers are same out of the factory, then the benefits of servo is just improving distortion and make the bass sound less boxy. Let us assume that for a moment. The Achilles heel in stoping boxy sound is the cone itself. We all build thick wall enclosure to stop the internal boxy sound from coming out through walls. But how about the cone? Does the boxy internal sound just magically avoid the cone? So after we build a thick wall enclosure, all the boxy sound now comes out from the cone. Servo reduces that boxy sound coming through the cone by up to 10x in energy becasue servo fight against any unintentional cone movement that is not in the signal source. To measure that you need to place another driver in the back of the enclsoure to emulate a source of boxy sound. Then you measure how much the cone moves under this pressure. One measurement for servo and one measurement for nonservo and you get the improvement. That is how much clarity servo can improve.

    Now if you look at another real world issue called variation which servo also helps. Variation consists of aging, unit to unit variation and batch to batch variation. There is an JL audio discussion on the version of firmware in those subs even for the same model. Why did they do that? It is batch to batch variation. It is like in a factory that you recalibrate your tool once in a while. Servo makes that easy because it is a close loop system that all variations that I have named above are reduced by the servo feedback.
    Last edited by RythmikAudio; 10-08-2016 at 04:20 PM.

  7. #27
    Join Date
    May 2007
    Location
    Stouffville,Ont..
    Posts
    280

    Default Re: Rythmik Audio 18s

    Thanks for explaining thing in layman terms. Rythmik was on my short list...hence my curiosity when I heard about the upcoming 18" designs.

    Unfortunately...a single sealed 18"...was not in the plan at this time....so I had to focus on those mfg who offer the compact design I need for my current needs.

    I'd like to experience a Rythmik product one day...in hindsight...I could have waited I suppose, given the current delays, not sure on when the new 18" will be coming out.

    Unfortunately, most of the local folks I know are into DIY designs.... thankfully...I have not gone down that rabbit hole, nor do I have any future plans in doing so.
    Speakers: Towers & Horizon(w RAAL), HTM200 SE finished in espresso satin
    Sub: Funk Audio 18 in Santos

    Source: Anthem MRX 300, Oppo BDP 103D
    Apple TV, Giga 1800, & Panny 54"

  8. #28
    Join Date
    Dec 2013
    Posts
    275

    Default Re: Rythmik Audio 18s

    Do the improvements from the Servo show up in measurements? Where would we see the improvement? FR? THD? Decay?

  9. #29
    Join Date
    Oct 2008
    Posts
    101

    Default Re: Rythmik Audio 18s

    Yes and No. In the FR response, the FR will be consistent throughout different SPL levels (other than the area where driver/amplifier runs out of juice). The important characteristic of sound reproduction is coherence. If the FR cannot maintain consistency at all time, the sound is said to exhibit memory effect or random variation. Now the latter is actually much better than the former. So how to we come up with a way to separate random variation from memory effect? None of the existing measurement methods can do that. In order to do that, one has to do a very long sequence measurement and do a huge amount of statistical measurements that is beyond most audio engineers. In fact that is the bottleneck of audio measurement. Audio engineers assume transeducers are "time-invariant" system. So it does not matter when you measure at time A or time B. In fact it does. If you have two tests A and B, the test results will be slightly different if do measurement A immediately before measurement B vs. the other order. That is called history, state-depedent, and memory effect. One simple demonstration is measure the FR using frequency sweep, but do it twice, one from low frequency to high frequency and another from high frequency to low frequency. For most systems, the results are slightly different. Will audio engineers make a fuzz over that? Some may comment it is just a random variation. But if you repeat 100 times and you always see the same trend, then it is not random. What one sees is the subtley of memory effect. Another example, there are two ways to measurement frequnecy response, one is use signal sweep and another use white noise signal. The problem of the former is 20hz response is measured at time A and 60hz is measured at time B. So it does not measurement the system at the same time, therefore the result is susceptive to the "state" of the system (similar to what I say sweep low to high vs high to low give you slightly different result). White noise based frequency response measurement on the other hand measures frequency response of all frequency points at the same time simultaneously. It is not as susceptive to the "state" and yet it begin to expose system with problem, for instance, the FR has a lot of small zig-zag vs a very smooth frequency response. So some engineer come up with 3rd octave smoothing, and the small zig-zags are gone. So a lot of techniques we use in measurement unintentionally erase important detail. The above is just the start.
    Last edited by RythmikAudio; 10-09-2016 at 06:33 PM.

  10. #30
    Join Date
    Jun 2016
    Posts
    12

    Default Re: Rythmik Audio 18s

    I have a 3-yr-old so drawn to down-firing. Is DIY (or Salk/Rythmik) the only option for down-firing right now? I was able to access an a D15SE link on Ascend via google search, but couldn't get there from within the Ascend site and it seems like it's maybe not part of the current offering.

    My room is about 8000 sq ft and I have an Outlaw LMF-1+ that doubles as end table, will probably get rid of when upgrading to Rythmik... what size of Rythmik would be appropriate for this room? I was told at one point that the best bet is two vented high-powered 15's... that the quality difference from sealed to vented Rythmik is not that much anymore and vented just has higher output. I would like to be able to use the sub(s) as end tables or coffee tables ideally; not sure from a cost/WAF/sound quality factor whether a center-of-room coffee table sub (maybe 2x12 or 2x15) would be better or maybe one on each sidewall - one of the two could be an end table. Or if the 18 comes out before I jump in, maybe just one that sits where my current one is... Also not sure if these big subs - especially when down-firing - can be held to the right height dimension.

    A lot in there - any input appreciated!

    Tai

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •