Sierra Tower w/RAAL in room response question

[jimlucci]

I have 2.1 setup (music only) with Sierra Towers w/RAAL + Rythmik L12.

Audio chain: PC w/Streaming service -> usb attached Schiit Modi 3+ Dac -> HK3490 Receiver -> Sierra Towers + Rythmik L12

I have been running numerous Room EQ's (w/miniDSP Umik) for baselines and speaker positioning and am getting a pretty steep LF rolloff starting at around 100Hz. It is at about 80 spl at 112Hz and falls to 43 spl at 50Hz. From 100Hz up to 20K it is pretty flat (between 70 spl and 80 spl). Readings that include the subwoofer in the test add some spl to that region (+10db) but the slope downward stays pretty much the same.

I expected to see a flatter response further into the lower frequencies and am wondering if my room has a lot to do with that (pretty big area) and/or that I might be pretty subwoofer deficient. Just wondering what other people have experienced with their in room responses with and without subwoofer.

Rough schematic of my room:
2281

[davef]

I have 2.1 setup (music only) with Sierra Towers w/RAAL + Rythmik L12.

Audio chain: PC w/Streaming service -> usb attached Schiit Modi 3+ Dac -> HK3490 Receiver -> Sierra Towers + Rythmik L12

I have been running numerous Room EQ's (w/miniDSP Umik) for baselines and speaker positioning and am getting a pretty steep LF rolloff starting at around 100Hz. It is at about 80 spl at 112Hz and falls to 43 spl at 50Hz. From 100Hz up to 20K it is pretty flat (between 70 spl and 80 spl). Readings that include the subwoofer in the test add some spl to that region (+10db) but the slope downward stays pretty much the same.

I expected to see a flatter response further into the lower frequencies and am wondering if my room has a lot to do with that (pretty big area) and/or that I might be pretty subwoofer deficient. Just wondering what other people have experienced with their in room responses with and without subwoofer.

Rough schematic of my room:
2281

Have you confirmed that your subwoofers are actually turning on using the REQ sweep? Run the sweep and put your hand on the woofers to make sure there is output. Rythmik subs have an auto-turn on feature that typically takes a few seconds to engage, which is longer than the REQ sweep time.

This is the first step to take for troubleshooting.

[jimlucci]

Yeah, I ran into that once or twice when moving the sub around, but got that procedure down. I made sure the sub is definitely on. To me the music sounds pretty good. Low freq. tracks like Hotel California Live/MTV 1994 kick drum sounds tight with good thump, mids and upper freq have great clarity, great detail. I wanted to use REW as an objective way to find the best speaker orientation for the room/space I have (it is rather large and irregular shaped due to adjoining room). I do zero HT with this setup, but also wondered how much of a difference a bigger sub (or additional one) would make given what I see in the REW output and also what others have found doing measurements in their rooms. I have included REW data below for my two different room orientation options (south and east). They seem similar in values, but I am a little new at interpreting results from REW. Any thoughts on my setup would be most welcomed!!

spl of both south and east main speaker positions:

(NOTE: THESE READINGS WERE TAKEN WHILE THERE WAS A PROBLEM WITH MY UMIK1. LEFT THEM HERE FOR THREAD CONTEXT ONLY)

2282

waterfalls of each:

east:

(NOTE: THESE READINGS WERE TAKEN WHILE THERE WAS A PROBLEM WITH MY UMIK1. LEFT THEM HERE FOR THREAD CONTEXT ONLY)

2283

south:

(NOTE: THESE READINGS WERE TAKEN WHILE THERE WAS A PROBLEM WITH MY UMIK1. LEFT THEM HERE FOR THREAD CONTEXT ONLY)

2284

[Mag_Neato]

I'll add my experience to this. I had a similar situation.... a pair of Sierra-2EX's, one 12" Rythmik sealed sub. I was excited to get REW +UMIK-1 and get a picture of how awesome my system was, because, of course, it HAD to be awesome! I was a bit disappointed, to put it mildly. Big dip from 80hz to 50hz, with a spike from 30 to 20hz. Since I had placed my mains where they sounded the best to me, I was left with moving the single sub around to try to fix the issue. No dice. I ended up buying a MiniDSP 2X4HD and a 2nd Rythmik F12. Once I settled on a good placement for the additional sub I began my REW+MiniDSP EQ'ing quest. I 1st got the 2 subs to sum with higher output in the region where I was getting the big dip. Once I had boosted the output there, I was able to use REW to create a EQ slope to cut the boosted peaks down to match the rest of the response. I then added another EQ curve that gave a slightly rising response from 80-30hz of about 10db to account for our poor low freq hearing.

I only EQ the subs from 80hz and lower. Nothing affects the mains. I run a full signal out from the sub out on my Parasound P6, letting the MiniDSP handle the crossover, and a filtered signal to my main amp from the mains output of the P6 crossed at 80hz high pass. I have it sounding pretty darn good right now.

That's my experience, YMMV.

[jimlucci]

Ed,

Thanks for sharing your experience with your setup and process - it is similar to mine. I have been working with REW for about 3 weeks now after reading the help guide and some other online documentation - mostly out of curiosity but also to get data measurements. Using REW has been very helpful in finding the best speaker locations and orientations in my room. It has also been helpful integrating the subwoofer with the towers (phase, crossover, gain). The phase adjustment had measurable REW differences depending on sub location (actual and relative to towers). Crossover and gain settings did as well (dropped the sub x-over to 55-60Hz put the sub gain at 11 oclock). I think I have it setup for my room (difficult space) about as good as I can without formal treatments (not a dedicated listening room) or equalization. Doing the same exercise by ear would have been difficult for me. I think it sounds damn good right now - tonally balanced, very tight, clear and detailed.

When you added your 2nd subwoofer what was the difference for you in sound and measurement?

I have the same dip/void in frequency (midpoint at 70Hz for me) that you and many others experience. I also begin a negative slope in the lower frequencies starting around 90Hz. I am just thinking I could address those 2 issues with the addition of another subwoofer. Then the question is which one? There also appears to be a lot of back-order status on Rythmik subs at the moment.

current REW graphs:

(NOTE: THESE READINGS WERE TAKEN WHILE THERE WAS A PROBLEM WITH MY UMIK1. LEFT THEM HERE FOR THREAD CONTEXT ONLY)

2285

(NOTE: THESE READINGS WERE TAKEN WHILE THERE WAS A PROBLEM WITH MY UMIK1. LEFT THEM HERE FOR THREAD CONTEXT ONLY)

2286

...Jim

[Mag_Neato]

Jim,

After adding the 2nd sub, with some placement experimentation and adjustments in the MiniDSP, I was able to get the 2 subs to sum together and boost the level in the dip area enough where I could then use REW's EQ prowess to cut the peaks down to a nice, flatter response. I then added a 10db rising curve from 80 to 30hz.

The biggest difference with the 2nd sub is that the bass is more even and there's tons more headroom.

[jimlucci]

Thanks Ed!

How big is your listening room/area? Do you do Home Theater too?

Jim

[Mag_Neato]

My listening room is a bonus room above the garage. It is roughly 11' wide x 27' long with roughly 4' tall knee walls that then angle up on both sides of the 27' length to an 8' flat ceiling. full carpeting. a door at one end and a window centered behind the speakers/equipment. Speakers are roughly 3' out from the front wall and 1-1/2' - 2' in from the side walls. I built corner traps for the front 2 corners and have 4 DIY acoustic panels placed at 1st-2nd reflection points on the side walls. I sit relatively close at about 7'.

I would post a pic of it but I've not had good luck posting pics on this forum and have been patiently waiting for the new updated site to launch, but Dave likes to tease us that it will happen soon!

My HT setup is on the 1st floor in the great room. I do not do any music listening there. It uses Klipsch in-wall/in-ceiling speakers in a 5.2.2(Front L/C/R & Rear L/R, 2 subs, 2 ceiling speakers) Atmos setup powered by a Denon X3300 AVR.

[jimlucci]

That is good size room you have. I am just trying to get a feel for what has lead others to go with multi subwoofer configs (they do a lot of HT or certain music profile or large open listening areas, to mitigate nulls, etc) I have read where others don't feel the need for any subwoofer much less multiples. When I look at my REW sweeps, it seems like I am light in spl from 20 - 90Hz - my listening experience/feel does'nt seem that way though.

[Mag_Neato]

I wonder if those who don't feel the need for a sub have actually taken room measurements with something like REW. If I had not then I'd never have been able to correct the response with the MiniDSP and a 2nd sub. I can certainly understand the K.I.S.S concept and not wanting to screw around with the setup process. Until you've experienced a full, balanced frequency response you don't know what you're missing.

[davef]

Yeah, I ran into that once or twice when moving the sub around, but got that procedure down. I made sure the sub is definitely on. To me the music sounds pretty good. Low freq. tracks like Hotel California Live/MTV 1994 kick drum sounds tight with good thump, mids and upper freq have great clarity, great detail. I wanted to use REW as an objective way to find the best speaker orientation for the room/space I have (it is rather large and irregular shaped due to adjoining room). I do zero HT with this setup, but also wondered how much of a difference a bigger sub (or additional one) would make given what I see in the REW output and also what others have found doing measurements in their rooms. I have included REW data below for my two different room orientation options (south and east). They seem similar in values, but I am a little new at interpreting results from REW. Any thoughts on my setup would be most welcomed!!

spl of both south and east main speaker positions:

2282



Are these measurements with or without the subwoofer?

[jimlucci]

Those are with the subwoofer. I did readings without the subwoofer as well but did not upload any of those....Jim

[curtis]

Those are with the subwoofer. I did readings without the subwoofer as well but did not upload any of those....Jim
I would be interested in seeing what those look like, as well as the subwoofer alone.

[davef]

Those are with the subwoofer. I did readings without the subwoofer as well but did not upload any of those....Jim

Hi Jim,

Please post or forward to me the measurements of just the subwoofer alone and each tower speaker (no subwoofer). Make sure the position of your microphone is at your main listening position and does not change for the various measurements.

Thanks!

[jimlucci]

Dave,

I will run those exact tests and get you the mdat file. I am starting to wonder if there is a problem with how the umik1 is picking up data (or how my laptop / umik1 are interacting). I checked REW preferences, calibration file selected, REW sweep notes and everything looks correct. The readings do not seem to reflect what I am hearing in my room, but being my first bunch of REW sweeps I don't have any frame of reference for the readings.

[davef]

Dave,

I will run those exact tests and get you the mdat file. I am starting to wonder if there is a problem with how the umik1 is picking up data (or how my laptop / umik1 are interacting). I checked REW preferences, calibration file selected, REW sweep notes and everything looks correct. The readings do not seem to reflect what I am hearing in my room, but being my first bunch of REW sweeps I don't have any frame of reference for the readings.

Jim, make sure the subwoofer's auto-on feature is turned off and the power is set to "ON" not "Auto". It is not possible for the sub to turn on instantly when the sweep starts, and even if it turns on a few milliseconds after the sweep starts, the measurement will not register properly.

With that steep bass roll off at 100Hz, there is no way you would be satisfied with the bass you hearing.

Also, please post the measurements. I only have REQ Wizard on an old laptop which I do not have here at the office.

[jimlucci]

Dave,

Will do with the sub switch - I have run into that. I will also just post the sweeps again here as well. The more I read and think about it, the more convinced I am that there is a problem with how my laptop integrates with the umik1 (certainly at frequencies under 100hz and likely across the spectrum). Soundcard interference, driver issues, windows 10, etc, etc). There have been people that have described similar REW issues using the brand/type of laptop that I am using.

[jimlucci]

Well, I don't know whether to laugh or cry. Just on a hunch, I took an older laptop that had less manufacturer device add-on's (ie. Realtech) and had both 2.0 and 3.0 usb ports, attached my Modi 3+ Dac and Umik1, set it up in my main listening position and ran a quick sweep from 10Hz - 20kHz - FLAT RESPONSE CURVE END TO END!!!! I am not sure where the problem lies with respect to my original laptop, but this laptop yields frequency response data more like what I was expecting. I am still playing around with the Umik1 connections to usb 2.0 and usb 3.0 on this laptop (they seem to behave slightly different, but I am not sure just yet). Once I am convinced that I have the setup on this new laptop correct, I will be running some controlled sweeps of my tower/sub setup and re-post them here. I think the insidious thing about this whole exercise is that the Umik1 partially worked. Had it not worked at all, I could have spent my time fixing a real problem instead of chasing my tail for 2 weeks.

[jimlucci]

I believe the problem with REW / Umik1 on my original laptop was the Windows input device setting check box "enable audio enhancements". I had this unchecked originally, but somehow it defaulted back to checked or selected (unplug/replug, reboot, I don't know)

From REW help doc:

There seems to be a growing trend for Windows laptops and PCs to apply noise cancellation processing to stereo microphone inputs, suppressing the content that is common to both channels. With USB microphones like the UMIK-1 the signal is the same on both channels, so it is all common content, and may be heavily suppressed.

Now, having a correctly operating REW tool/Umik1, I ran through the process of integrating the Rythmik L12 with the Sierra Towers again. What a difference!!!! I was able to run a series of sweeps dialing in delay/phase, crossover and gain. I was even able to add a peq setting on the L12 to soften a single peak in the 35Hz area.

I may rerun through some of the speaker position/room orientation sweeps again this coming week, but things look much better now - it always sounded great!

Big thanks to Ed, Dave and Curtis for helping me out here!!!!

Dave - being that the REW data I posted earlier in this thread is garbage, do you want me to remove it or replace it with legitimate REW data?

Here is a quick post of my new data (room setup as I originally diagramed):

2287

2288

[racrawford65]

Glad you got it figured out and dialed in, Jim.
Robert

[jimlucci]

Thanks Robert!

REW/Umik1 is a nice tool for finding the right speaker location/positions and integrating the subwoofer with the mains (when everything is working right). I may do some tweaking here and there, but to be honest, I am very happy with these Sierra Towers in my room. I may add another sub to the mix but based on how it sounds and the measurements, it is not a pressing issue for me...Jim

[racrawford65]

Yes, REW is a great tool. I love my Sierra Towers too.

[davef]

Well, I don't know whether to laugh or cry. Just on a hunch, I took an older laptop that had less manufacturer device add-on's (ie. Realtech) and had both 2.0 and 3.0 usb ports, attached my Modi 3+ Dac and Umik1, set it up in my main listening position and ran a quick sweep from 10Hz - 20kHz - FLAT RESPONSE CURVE END TO END!!!! I am not sure where the problem lies with respect to my original laptop, but this laptop yields frequency response data more like what I was expecting. I am still playing around with the Umik1 connections to usb 2.0 and usb 3.0 on this laptop (they seem to behave slightly different, but I am not sure just yet). Once I am convinced that I have the setup on this new laptop correct, I will be running some controlled sweeps of my tower/sub setup and re-post them here. I think the insidious thing about this whole exercise is that the Umik1 partially worked. Had it not worked at all, I could have spent my time fixing a real problem instead of chasing my tail for 2 weeks.

Very happy you resolved the issue! Yes, please post the measurements now, I always enjoy looking at these.

Your issue is one of the reason I generally don't trust measurements taken using laptops / PC's etc. I have a very old and basic laptop (Windows XP) that is fully dedicated to trying out software like REW.

[jimlucci]

In an effort to remove any effects from the Windows audio stack and have equalizer capabilities, I have installed EqualizerAPO and removed the original APO's (windows/realtech maybe?). I ran very modest equalizer parameters in the REW EQ feature, created a .txt file of filters and loaded these into EqualizerAPO (only 3 filters all under 120Hz). My room is pretty heavily furnished, but I am not really able to install room treatments (not a dedicated listening area). Here is an spl and waterfall of my Sierra Towers w/RAAL and Rythmik L12 subwoofer:

SPL:

2289

Waterfall:

2290

....Jim

[davef]

In an effort to remove any effects from the Windows audio stack and have equalizer capabilities, I have installed EqualizerAPO and removed the original APO's (windows/realtech maybe?). I ran very modest equalizer parameters in the REW EQ feature, created a .txt file of filters and loaded these into EqualizerAPO (only 3 filters all under 120Hz). My room is pretty heavily furnished, but I am not really able to install room treatments (not a dedicated listening area). Here is an spl and waterfall of my Sierra Towers w/RAAL and Rythmik L12 subwoofer:

SPL:

2289

Waterfall:

2290

....Jim

Hey Jim,

Looks great, but it does appear phase integration between the sub and the speakers can be improved. Rythmik has some good info regarding this:

https://www.rythmikaudio.com/phase1.html

[jimlucci]

Hey Jim,

Looks great, but it does appear phase integration between the sub and the speakers can be improved. Rythmik has some good info regarding this:

https://www.rythmikaudio.com/phase1.html

Thanks Dave - I have revisited that reference again. Rythmik has very good info/explanation regarding alignment of mains and subs.

Because my HK3490 has no eq, delay or crossover adjustability do you think there would be any benefit in my setup by adding a 2X4 minidsp module between the pre-amp out and amp in connections? I am thinking that would allow more timing control between the mains and the sub as well as pass filter capability and eq if I wanted. As it stands the only timing alignment options I have are speaker/sub location and the delay/phase control provided on the Rythmik L12.

I am going to play around with separate measurements of each main and the L12 to see if I can get them
to all align better with positional modifications and the phase/delay on the L12. I have not re-run sweeps like that since I corrected the problem with REW and Umik1.

[davef]

Thanks Dave - I have revisited that reference again. Rythmik has very good info/explanation regarding alignment of mains and subs.

Because my HK3490 has no eq, delay or crossover adjustability do you think there would be any benefit in my setup by adding a 2X4 minidsp module between the pre-amp out and amp in connections? I am thinking that would allow more timing control between the mains and the sub as well as pass filter capability and eq if I wanted. As it stands the only timing alignment options I have are speaker/sub location and the delay/phase control provided on the Rythmik L12.

I am going to play around with separate measurements of each main and the L12 to see if I can get them
to all align better with positional modifications and the phase/delay on the L12. I have not re-run sweeps like that since I corrected the problem with REW and Umik1.

Hi Jim,

All you really need is the phase control on your sub. This is the first and simplest step, we can revisit if you don't get better results.

[djDANNY]

Thanks Dave - I have revisited that reference again. Rythmik has very good info/explanation regarding alignment of mains and subs.

Because my HK3490 has no eq, delay or crossover adjustability do you think there would be any benefit in my setup by adding a 2X4 minidsp module between the pre-amp out and amp in connections? I am thinking that would allow more timing control between the mains and the sub as well as pass filter capability and eq if I wanted. As it stands the only timing alignment options I have are speaker/sub location and the delay/phase control provided on the Rythmik L12.

I am going to play around with separate measurements of each main and the L12 to see if I can get them
to all align better with positional modifications and the phase/delay on the L12. I have not re-run sweeps like that since I corrected the problem with REW and Umik1.

It looks like you would benefit from some EQ, so I would recommend going for the minidsp since you don’t have a receiver with auto calibration. Your freq response in the subwoofer region looks like you’re +/- 7 dB (14 dB swing from the high to the low). Your 10dB axis makes the response look smoother than it really sounds.

[racrawford65]

or a dSpeaker antimode. Works really well on eq'ing subs and does it automatically. I used one for a bit when my miniDSP was having issues.

[curtis]

As Dave says, he needs the phase control on the sub. Phase integration is important, at least as important as EQing.

With two people, it is pretty easy. Say your crossover is set for 80hz. Have one person with an SPL meter sitting at the listening position, have the other person adjusting phase. Play an 80hz tone, and while adjusting the phase, watch the SPL meter. As you are adjusting the phase, you will see the output on the meter vary...at its highest output point, that is when the phase is correct at 80hz. Play the tone through the system, not just the sub, so that the crossover and mains are in effect.

Any device that just works on the sub, is not going to correct phase with the mains.

[djDANNY]

As Dave says, he needs the phase control on the sub. Phase integration is important, at least as important as EQing.

With two people, it is pretty easy. Say your crossover is set for 80hz. Have one person with an SPL meter sitting at the listening position, have the other person adjusting phase. Play an 80hz tone, and while adjusting the phase, watch the SPL meter. As you are adjusting the phase, you will see the output on the meter vary...at its highest output point, that is when the phase is correct at 80hz. Play the tone through the system, not just the sub, so that the crossover and mains are in effect.

Any device that just works on the sub, is not going to correct phase with the mains.

Phase alignment with the mains should really be your last step after EQing the subs and setting proper gains/levels first.

[jimlucci]

Today I ran sweeps of just the Towers individually, together and then with the Subwoofer. I tried different positions within my room and finer adjustments within those positions. With the mains, I found that no matter what positions within the room I used, there was at least one and often 2 or 3 pretty big peaks and nulls (focusing mostly under 500Hz). What I learned with that exercise was that there was no clearly superior position for my Towers within my space. With that, I set the mains as per my original room diagram - this position had the least amount and severity of peaks and nulls.

I then ran sweeps with just my L12 (crossover 80, slope 24, peq off) in different room positions. Unlike with the Towers, there were really only 2 positions in the room that stood out (plus I did not have to worry about directional issues with the sub placement). One position covered the sharp null in the Towers at around 80Hz, but was generally worse other than that. The other position was much better under 60Hz but had the same sharp null at around 80Hz that the Towers had. I chose this second position and ran the sweeps with the Towers while adjusting for delay/phase. It was clear in the response curves when the sub was adjusted differently from 0 to 180deg where it aligned best with the towers. After the phase was set, I used the peq option on the L12 to soften a peak at around 30Hz.

Conclusions:

I do believe that if I added another L12 in the other sub location I could certainly smooth and enhance my lower frequency range.

Unless I can do some sort of room treatments and/or equalization this is the best I can do within my space. I think the adjacent room behind my mlp is causing most of the irregularities in my freq response.

Measurements aside, I find that these Sierra Towers and the Rythmik L12 sound incredible. They play plenty loud without a hint of strain. The bass is tight and authoritative, the mids and highs are clear and detailed. The RAAL tweeters are just amazing - in all the time I have spent listening, I have never felt that fatiguing sensation.

Advice, insights are always welcomed.

2291

2292

[davef]

Phase alignment with the mains should really be your last step after EQing the subs and setting proper gains/levels first.

Actually, just the opposite. Phase issues between the sub and speakers will cause peaks and nulls in the response that cannot be corrected by EQ (it will only make them worse). Once phase on the sub is properly set, EQ'ing becomes much simpler as you are then simply adjusting for room acoustics.

[davef]

Today I ran sweeps of just the Towers individually, together and then with the Subwoofer. I tried different positions within my room and finer adjustments within those positions. With the mains, I found that no matter what positions within the room I used, there was at least one and often 2 or 3 pretty big peaks and nulls (focusing mostly under 500Hz). What I learned with that exercise was that there was no clearly superior position for my Towers within my space. With that, I set the mains as per my original room diagram - this position had the least amount and severity of peaks and nulls.

I then ran sweeps with just my L12 (crossover 80, slope 24, peq off) in different room positions. Unlike with the Towers, there were really only 2 positions in the room that stood out (plus I did not have to worry about directional issues with the sub placement). One position covered the sharp null in the Towers at around 80Hz, but was generally worse other than that. The other position was much better under 60Hz but had the same sharp null at around 80Hz that the Towers had. I chose this second position and ran the sweeps with the Towers while adjusting for delay/phase. It was clear in the response curves when the sub was adjusted differently from 0 to 180deg where it aligned best with the towers. After the phase was set, I used the peq option on the L12 to soften a peak at around 30Hz.

Conclusions:

I do believe that if I added another L12 in the other sub location I could certainly smooth and enhance my lower frequency range.

Unless I can do some sort of room treatments and/or equalization this is the best I can do within my space. I think the adjacent room behind my mlp is causing most of the irregularities in my freq response.

Measurements aside, I find that these Sierra Towers and the Rythmik L12 sound incredible. They play plenty loud without a hint of strain. The bass is tight and authoritative, the mids and highs are clear and detailed. The RAAL tweeters are just amazing - in all the time I have spent listening, I have never felt that fatiguing sensation.

Advice, insights are always welcomed.

2291

2292

That 10dB null at 80Hz, then 10dB boost 1/2 octave lower is a phase issue. Have you played with the phase control on your sub as Curtis advised?

[davef]

With two people, it is pretty easy. Say your crossover is set for 80hz. Have one person with an SPL meter sitting at the listening position, have the other person adjusting phase. Play an 80hz tone, and while adjusting the phase, watch the SPL meter. As you are adjusting the phase, you will see the output on the meter vary...at its highest output point, that is when the phase is correct at 80hz. Play the tone through the system, not just the sub, so that the crossover and mains are in effect.

Excellent post and a very simple method to use.

[jimlucci]

That 10dB null at 80Hz, then 10dB boost 1/2 octave lower is a phase issue. Have you played with the phase control on your sub as Curtis advised?

Yeah, I tried 0 to 12ms (0 to 180deg) and everything in between. I get same dip when I run the Towers alone (no subwoofer at all). I seem to get a sharp dip around 80 and 200 when running just the Towers no matter where I set them in the room (it is always there maybe shifted slightly). Is it possible the Towers are out of phase? or a problem with one of the woofers?

I also had a bad thought about a why there could be a problem. I did run them at some point with the grilles oriented incorrectly (see post started by racrawford65). The upper woofer in each Tower are the drivers that were affected, but they appear to be operating correctly. I know a test that would prove/disprove that, but before I do anything, I want to make sure I am not chasing a ghost here. I know in room responses can vary significantly, so I don't really know what to expect. Could'nt room modes/boundary issues cause those?

Here is a close up of the Towers from 10-500Hz in room without subwoofer:

[jimlucci]

Excellent post and a very simple method to use.

I tried this idea and it confirmed my phase setting. I ran a low frequency (30-80Hz) continuous tone while adjusting my phase dial. 0 deg (0 ms) was about 82 spl. 180deg (12ms) was about 88 spl.

Good idea there. Thanks Curtis!!

[curtis]

I tried this idea and it confirmed my phase setting. I ran a low frequency (30-80Hz) continuous tone while adjusting my phase dial. 0 deg (0 ms) was about 82 spl. 180deg (12ms) was about 88 spl.

You should just run an 80hz tone, if that is where your crossover is set. You don't want anomalies from other frequencies with their room interactions to affect the SPL. 80 hz is where you want the phase to be correct.

[curtis]

Jim...do you run the speakers large or small? Are you sending the frequencies below 80hz to the speakers as well as the sub?

[curtis]

and can you run a 10hz to 500hz sweep with just the sub?

[Mag_Neato]

Curtis, REW will allow you to set the test sweep to whatever frequencies you wish.

[jimlucci]

Jim...do you run the speakers large or small? Are you sending the frequencies below 80hz to the speakers as well as the sub?

yes. The hk3490 does not have any ability natively to limit freq to the Towers. It has 2 rca outs for the subwoofer connection. It is basic 2 or 2.1 receiver....Jim

[jimlucci]

Curtis, REW will allow you to set the test sweep to whatever frequencies you wish.

I am going to find that option and rerun the phase test again with just a 85Hz tone (which is where I am crossed over on the sub)....Jim

[jimlucci]

You should just run an 80hz tone, if that is where your crossover is set. You don't want anomalies from other frequencies with their room interactions to affect the SPL. 80 hz is where you want the phase to be correct.

Interesting. I did find where you can run a specific pink noise tone at only 85Hz (where my xover is set on the sub). I ran it for 2 minutes with mains and sub all on. I watched the REW spl meter while my Umik1 was in my mlp. The highest spl was at the 0deg and 180 deg (180 being a bit higher), but the 90 deg (middle) was much lower. Very good way to test phase!!

[jimlucci]

and can you run a 10hz to 500hz sweep with just the sub?

Sub only 10 to 500Hz:

2295

[Mag_Neato]

Is that with the PEQ filter off?

[jimlucci]

Is that with the PEQ filter off?

Doh! I did have a peq set at 30Hz. Here it is with peq off:

2296

[curtis]

yes. The hk3490 does not have any ability natively to limit freq to the Towers. It has 2 rca outs for the subwoofer connection. It is basic 2 or 2.1 receiver....Jim
So essentially you are not using a crossover, you are just filtering what the sub is playing.

The HK has a pre/out and main/in connections. You should run the pre/out to the sub's line-in, use the sub's highpass filter, and from the sub's HPF out back to the HK's main/ins.

Without a proper crossover, I don't even think you can call the receiver a 2.1.

That said, from your sweep of your mains, it looks like your room has a huge suckout at 70hz. What does the sweep look like one speaker at a time?

[racrawford65]

Unfortunately, it doesn't look like the L12 has an HPF out. So, could run the subpreamp to the Rythmik line-in and use cross-over/phase on the sub. His Towers would still run full range, though.

It's similar to what I do with my Rogue RP5 - run the 1st pair of outs to the amp driving the towers and the second pair to my miniDSP 10x10 (which feeds line in on my E15s). I use the E15 controls for cross-over & phase. My Towers run full range. I could actually cross the Towers if I ran the L/R outputs to the miniDSP and then on to the amp. As I'm mostly vinyl, trying to avoid digitizing as much as possible so I don't do that.

I don't recall if Jim has a miniDSP in his system so not sure if that is a solution without additional cash outlay. He could run the main L/R outs into the miniDSP and then outputs to FL, FR and sub. An alternate to the miniDSP could be one of the dSpeaker products (I think the Antimode is the one for stereo systems).

[jimlucci]

Curtis, you are correct. I am running full range to Towers and Sub and the xover on the L12 sub is just a limiter. Earlier in this thread I posed the question to Dave about inserting a 2X4 Minidsp between between the preamp and amp jumpers on the hk3490 - which I would definitely do if it gave me a benefit. I think he wanted to make sure I had everything else setup before I went down that path.

You are also correct that I have a huge suck out at around 70Hz (and a smaller one at around 200Hz) - I am not sure what that is. It shows up in also when I run the Towers only (Sub off). One of the towers has a pronounced peak/dip in that freq range. The other Tower has a smaller dip at 70Hz that aligns with it.

I am not that familiar with REW results and what would be considered normal. I am also suspicious of the REW tool and/or laptop too. The Towers and Sub all seem to be operating normally. Can room modes and boundaries cause these types of results?

Here are the mains (no sub) individually - left in blue - right in orange.


2297

[curtis]

Can room modes and boundaries cause these types of results?
Absolutely!

This is where placement and room treatment comes into play.

That miniDSP should also control sub output. Currently, you really don't have much to adjust the integration of your mains and sub. That is why I suggested using the HPF on the sub between the preamp and amp inputs on the HK.

[curtis]

Unfortunately, it doesn't look like the L12 has an HPF out.
OK...then my suggestion won't work. :(

Yes...something like the miniDSP would be very useful. Does the Antimode do high-pass?

[curtis]

Oooh...miniDSP has a new model. I would be all over this if I had a 2-channel rig with a sub.

https://www.minidsp.com/products/minidsp-in-a-box/flex

[jimlucci]

Absolutely!

This is where placement and room treatment comes into play.

That miniDSP should also control sub output. Currently, you really don't have much to adjust the integration of your mains and sub. That is why I suggested using the HPF on the sub between the preamp and amp inputs on the HK.

I did try many different room placements and orientations, but was not able to affect the large nulls and peaks in the 10-500Hz range - I guess I thought I would see more of a change in response than I did. I also measured each Tower individually pointing the Umik1 directly at each speaker from a meter away, no change in measurement (not sure that is a legit test though).

Everything appears to be working as it should - just some anomalies in either the readings or the room. I don't have a lot of experience reading these, so that is why I figured I would ask here.

[davef]

Hi Jim,

We are jumping too far ahead here.

First off, there is nothing wrong with your sub, towers or receiver. Your in-room response looks good and you are fully enjoying the sound. +/- 10dB swings (and even higher) are perfectly normal for an in-room response.

I didn't realize you are running the towers full range, that changes things dramatically with regard to what is causing that dip at ~ 80Hz. More than likely, and as others pointed out, it is simply a null at your listening position. You can keep the towers and sub where they are and place the mic at different positions in your room and you will see things change.

Now, assuming you are NOT using the LFE input on the L12 (in your setup, you should not be) - I recommend turning the low pass filter on the sub all the way up, and then adjust the phase setting on the sub using an 80Hz sine wave (not a sweep) with REW can generate for you. As Curtis mentioned, use an SPL meter and set the phase to where the output level is highest. You must run the towers and sub together for this.

This is the best you can do in your situation unless you want to change your listening position.

If it were me, and I was going to spend some additional $$$, I would get a modern receiver with bass full management, auto EQ such as Audyssey or DIRAC etc., and pre-outs. This way you can properly integrate sub and speakers and the Auto-EQ function will easily compensate for that dip.

That being said, after all that - you may or may not even hear a difference. This is one of the problems when consumers now have readily available access to software like REW. They begin to think something is "wrong" and the majority have little understanding of room acoustics. It is shocking to me how much more time I spend these days assisting people with understanding measurements they take of their rooms. It has gone from perhaps 1-2 hours per week to at least an hour per day just in the past 2 years, especially during COVID lockdowns.

Again, don't go nuts with this, sometimes room issues can not be solved - and even worse, sometimes the solution makes things even worse. Enjoy the system!

[davef]

Jim,

In addition, your room is nearly a perfect square. Those are the worst dimensions for an even room response below the Schroeder frequency. Based on the room dimensions, you have a very strong axial mode and a strong tangential mode at ~74Hz. That is what you are seeing in your measurements. Ideally, you never want to see axial and tangential modes at the same frequency, but this is the issue with square or nearly square rooms.

2 subs will help, as will my suggestion about raising the LPF and adjusting phase, and you will also need EQ to fill in the rest - if you want to try and get rid of the null. No amount of room treatment available to you will help with your null as it is too low in frequency, so don't waste your money and time trying room treatments. Also, understand that correcting this null at your listening position will cause problems in other areas of the room, not a big deal if you only listen at this one position though...

You can also set the PEQ on the L12 to the same frequency as the null, and adjust the boost amount...

[jimlucci]

Hi Jim,

We are jumping too far ahead here.

First off, there is nothing wrong with your sub, towers or receiver. Your in-room response looks good and you are fully enjoying the sound. +/- 10dB swings (and even higher) are perfectly normal for an in-room response.

I didn't realize you are running the towers full range, that changes things dramatically with regard to what is causing that dip at ~ 80Hz. More than likely, and as others pointed out, it is simply a null at your listening position. You can keep the towers and sub where they are and place the mic at different positions in your room and you will see things change.

Now, assuming you are NOT using the LFE input on the L12 (in your setup, you should not be) - I recommend turning the low pass filter on the sub all the way up, and then adjust the phase setting on the sub using an 80Hz sine wave (not a sweep) with REW can generate for you. As Curtis mentioned, use an SPL meter and set the phase to where the output level is highest. You must run the towers and sub together for this.

This is the best you can do in your situation unless you want to change your listening position.

If it were me, and I was going to spend some additional $$$, I would get a modern receiver with bass full management, auto EQ such as Audyssey or DIRAC etc., and pre-outs. This way you can properly integrate sub and speakers and the Auto-EQ function will easily compensate for that dip.

That being said, after all that - you may or may not even hear a difference. This is one of the problems when consumers now have readily available access to software like REW. They begin to think something is "wrong" and the majority have little understanding of room acoustics. It is shocking to me how much more time I spend these days assisting people with understanding measurements they take of their rooms. It has gone from perhaps 1-2 hours per week to at least an hour per day just in the past 2 years, especially during COVID lockdowns.

Again, don't go nuts with this, sometimes room issues can not be solved - and even worse, sometimes the solution makes things even worse. Enjoy the system!

Thanks Dave!

I can definitely see how people might go down the measurement bunny-hole - I am not interested in doing that to be sure. I will say, however, it has been a good learning/understanding exercise. Thanks for your advice and input on this. I think I have everything setup about as good as I can in my environment and as I have said from the beginning - it sounds amazing!

[jimlucci]

Jim,

In addition, your room is nearly a perfect square. Those are the worst dimensions for an even room response below the Schroeder frequency. Based on the room dimensions, you have a very strong axial mode and a strong tangential mode at ~74Hz. That is what you are seeing in your measurements. Ideally, you never want to see axial and tangential modes at the same frequency, but this is the issue with square or nearly square rooms.

2 subs will help, as will my suggestion about raising the LPF and adjusting phase, and you will also need EQ to fill in the rest - if you want to try and get rid of the null. No amount of room treatment available to you will help with your null as it is too low in frequency, so don't waste your money and time trying room treatments. Also, understand that correcting this null at your listening position will cause problems in other areas of the room, not a big deal if you only listen at this one position though...

You can also set the PEQ on the L12 to the same frequency as the null, and adjust the boost amount...

I definitely think another sub would help in my room. I had anticipated doing that when I bought the Towers and the L12 in the beginning. The REW measurements did help find the best spot for the Subwoofer I have (which is different than where I had it) and also helped phase align it with the mains, but I can see where people can get obsessive about readings - not something I am interested in doing....JC

[racrawford65]

OK...then my suggestion won't work. :(

Yes...something like the miniDSP would be very useful. Does the Antimode do high-pass?

The Antimode Dual Core does (both HP & LP). The Antimode 8033 only has LP.

[djDANNY]

Actually, just the opposite. Phase issues between the sub and speakers will cause peaks and nulls in the response that cannot be corrected by EQ (it will only make them worse). Once phase on the sub is properly set, EQ'ing becomes much simpler as you are then simply adjusting for room acoustics.

I get what you’re thinking but in real life practice, unless you were good at creating the proper filters manually, it’d be pretty difficult. I personally like to start with having as flat of a frequency response as I can get for both the speakers and sub and let the proper crossover slopes allow them to summate to be flat (no different than how you would design a speaker with two drivers). That means I EQ first, then get the phase between speakers and sub aligned as much as possible over the crossover range. You could do it the way you suggested but now you’re running sweeps that have combined outputs of the speakers and sub and then trying to just EQ one to affect the summed response in the crossover region. Not impossible to do but not the preferred method in my opinion. Much easier to EQ both separately then phase align them after.

[Mag_Neato]

I get what you’re thinking but in real life practice, unless you were good at creating the proper filters manually, it’d be pretty difficult. I personally like to start with having as flat of a frequency response as I can get for both the speakers and sub and let the proper crossover slopes allow them to summate to be flat (no different than how you would design a speaker with two drivers). That means I EQ first, then get the phase between speakers and sub aligned as much as possible over the crossover range. You could do it the way you suggested but now you’re running sweeps that have combined outputs of the speakers and sub and then trying to just EQ one to affect the summed response in the crossover region. Not impossible to do but not the preferred method in my opinion. Much easier to EQ both separately then phase align them after.

With REW, you create the EQ curve you desire and REW creates the filters. You simply export them and load them onto your DSP device, in my case the MiniDSP 2x4HD.

[djDANNY]

With REW, you create the EQ curve you desire and REW creates the filters. You simply export them and load them onto your DSP device, in my case the MiniDSP 2x4HD.

Exactly. If you want to go that route (have REW generate the filters), you want to do it the way I suggested where you EQ the sub by itself first… it wouldn’t work properly if your measurement was a combined sub and speaker sweep. There’s no tangible benefit (especially if you have multiple subs) to try to do any phase alignment with mains before getting the subs set up properly. I’m fact, with multiple subs, that is strictly impossible to do if you want to do it the proper way.

[Pogre]

I've spent a lot of time learning to use REW and a MiniDSP and have managed to get some great results.

2303

2304

After I get it nice and flat I do my house curve.

2305

There's a bit of a learning curve but it was definitely worth the effort for me. My "before" is pretty bad.

[jimlucci]

Looks very good! How many EQ filters did REW generate? Did you equalize the entire range or limit filters to below a certain freq?

[Pogre]

Looks very good! How many EQ filters did REW generate? Did you equalize the entire range or limit filters to below a certain freq?
Thank you! I've put some time into it.

I limit to below 400 hz and focus on bass frequencies. I don't remember how many filters were generated but there are a few.

I run Audyssey first and it gets me pretty close. After that I do my sweeps, generate my filters in REW and do just a tiny bit of tweaking after that. I have 3 big subs in my room too and they're pretty responsive to adjustments.

[davef]

I've spent a lot of time learning to use REW and a MiniDSP and have managed to get some great results.

2303

2304

After I get it nice and flat I do my house curve.

2305

There's a bit of a learning curve but it was definitely worth the effort for me. My "before" is pretty bad.

Looks great!