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Discussion Starter · #1 ·
I have been unhappy with the bass response in my room. Based on the listening position I have had to run my subs hot by about 6dB to get them to sound good from my position. However, the other seating positions are overloaded with bass. So I moved the subs to the positions you see in the diagram of my room below. That made it seem like there was less disparity between the primary and the other listening positions. Right now I have a good sub (Rythmik F15) and an ok sub (Emotiva Ultra 12) and have been trying to integrate them. Because of the uneven bass problems, I started contemplating replacing the Emotiva sub with another Rythmik F15. But, before I did that, I decided to do some real measuring and get REW up and running. The two subs were level matched using Audyssey auto setup (both set at 80dB.)


My first test was with the room as is (as is shown in the diagram below). As best I can determine from the graphs, the frequency response is very uneven at the primary listening position with the subs where they are (were).


So, I moved the subs so that they were even with the front towers. That seemed not to help the frequency response, and may have made it worse.


Next I move the subs to the corners along the front wall. This helped to even out the frequency response, but the listening positions other than the primary all had very overpowering bass again when tuned for the primary listening position.


Finally I moved the subs to the 1/4 and 3/4 position along the front wall. This resulted in what I think is the best or flattest frequency response. But the other listening positions are still bad.


So I don't really know where to go from here. As you can see from my room diagram, I am very limited as to where the subs can go. There is a lot of furniture and other items in the room, and it is also the living room, so I am dealing with that.


Please check out the diagram and the graphs I have posted below and tell me what you think. Keep in mind, the graphs might not be exactly right, my interpretation of them may not be right, or a combination of both...


I have ordered a 2nd Rythmik F15 to replace the Emotiva. The goal with this testing was to get a good idea where I am going to place the subs so that when the new sub gets here, I can just place them and re-calibrate. Not interested in dragging 2 100 subs all over the room...


First, all the particulars:

Sub 1 - Rythmik F15

Sub 2 - Emotiva Ultra 12 (sealed) (I have ordered a second Rythmik F15 to replace this)

AVR = Denon AVR 4311 (Audyssey Multi XT32)

front stage and side surrounds powered by Emotiva XPA5

FL & FR = Paradigm Studio 100 - V1

CC - Paradigm CC-470 - V3 (I think)

SL & SR = Paradigm Studio 20 - V1

SBL & SBR = Definitive Technologies SM350

NO room treatments

All REW graphs run with Audyssey turned OFF

All SPL graphs depict FL+sub and FR+sub

All graphs done with mic in primary listening position at ear level, mic calibration file for 90 degrees used.


The room is used 60%video/TV and 40% for music. But much more critical listening for music than video/TV.



First, here is the diagram of my room and note where the subs were. A couple of notes here. There is about 30 inches from the back of the media/TV stand to the front wall. The room is set up this way because its easier to get to the wiring and also to get the mains away from the walls and also with the idea that the subs can be back there.



First test - ROOM AS IS


All APL - room as is (note the very uneven frequency response - remember with the subs in this position the other seating positions the bass was not quite as overpowering as when the subs are place along the front wall. Notice the huge dips in response with the FR+sub - That is the side the Rythmik sub is on.



Waterfall - room as is

FL+subs



FR+subs




Decay - room as is

FL+subs



FR+subs




Now for the second test - SUBS EVEN WITH MAINS (I moved them back from original position about 12 inches to even them with mains) - It did not help, may have hurt. Just going to post the All SPL graph for this one. The Waterfall and decay graphs look equally unimpressive. I do not understand this, particularly the FR+sub line which shows the HUGE dips.


All SPL - subs even with mains



Now for the third test - SUBS IN FRONT CORNERS - this is when things started getting better in terms of flatter response at the primary listening position...but worse in terms of the other listening positions now suffering overpowering bass


All SPL - subs in front corners




Waterfall - subs in front corners

FL+subs



FR+subs




Decay - subs in front corners

FL+subs



FR+subs




And finally the forth test - SUBS AT 1/4 AND 3/4 ON FRONT WALL - based on my inexpereinced eyes on the REW graphs this is the best overall. Not so much from the flattness of the frequency response as it is comparable to when the subs are placed in the front corners. But notice how much better the waterfall looks. But the other seating positions still experience very bloated bass with the subs in these positions.


All SPL - Subs at 1/4 & 3/4 front wall





Waterfall - Subs at 1/4 & 3/4 front wall

FL+subs




FR+subs






Decay - Subs at 1/4 & 3/4 front wall

FL+subs




FR+subs





I actually ran a 5th test with the Rythmik on the front wall at 1/4 and the Emotiva on the back wall at 3/4. I could not match them 1/4 to 1/4 or 3/4 to 3/4. Anyway, the frequency response was all over the place. So I am not posting those graphs.


I appreciate any comments or helpful suggestions that you can give. Thanks
 

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Did you level match the subs? They are out of phase at the xo. If possible put one in a front corner and the other in the rear on a diagonal.
 

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Discussion Starter · #3 ·
Yeah I was wondering if I had a phase issue. The phase knobs on both subs are set at 0 but how do I figure out which sub is out of phase. And how to I determine what the phase should be set at? There is a possibility I can put the subs at front left and right rear corners. But can't do that and re measure until this weekend. But isn't the bigger issue the phase situation? Will moving the subs to where you suggest flatten out the response much from where they are now? Or is that more to reduce the overpowering amount of bass in the other listening positions?


If I need to play with the phase knobs and rerun the graphs what am I looking for on the graphs to determine they are in phase? Funny thing is when I start the Audyssey auto calibration both subs come back the approx distance they are from the MLP. Not a lot of difference between the distances of the two subs. Which is why I am left guessing.
 

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Discussion Starter · #4 ·
Oh and yes the subs were level matched using the beginning of the Audyssey auto calibration. Both set to roughly 80dB
 

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It looks like you cross at 80 Hz and that may be where the phase issue is. If there is no null at the XO point, then it is probably room related and not a phase issue.


Just try to flip the phase switch on one sub and see if it improves. if you have a dial, crank it to 180° to start if it was at 0° first and see if it kills the null. Try first one then both subs until it looks better.


Otherwise, for the 80 Hz null (assuming that is your XO point) you could also try the distance tweak (just gradually increase the distance on your subs in the AVR until the null is decreased, it may take several feet of change or maybe less)


It helped my bass response to cross all speakers at the same XO (all 80 Hz now) instead of how it was before (80 hz center and surrounds, and 60 Hz mains). That just meant that the subs AND the mains were both playing 60-80 Hz tones which partially cancelled each other out.


I also recommend you do the sub crawl first and then start measuring. While it is subjective, it gives you a good starting point for placement.


I have a tricky room for bass and it has really helped me (also using XT32 with the X4000).


since you have two different subs, do it for both of them. If the output is similar it may not be necessary, but if they are vastly different, it is a good idea.


good luck!


Getting a decent response for bass is hard work, but well worth it in the end!
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by McStyvie  /t/1523385/first-attempt-at-rew-nee...placement-of-my-subs-in-my-room#post_24506354


It looks like you cross at 80 Hz and that may be where the phase issue is. If there is no null at the XO point, then it is probably room related and not a phase issue.


Just try to flip the phase switch on one sub and see if it improves. if you have a dial, crank it to 180° to start if it was at 0° first and see if it kills the null. Try first one then both subs until it looks better.


Otherwise, for the 80 Hz null (assuming that is your XO point) you could also try the distance tweak (just gradually increase the distance on your subs in the AVR until the null is decreased, it may take several feet of change or maybe less)


It helped my bass response to cross all speakers at the same XO (all 80 Hz now) instead of how it was before (80 hz center and surrounds, and 60 Hz mains). That just meant that the subs AND the mains were both playing 60-80 Hz tones which partially cancelled each other out.


I also recommend you do the sub crawl first and then start measuring. While it is subjective, it gives you a good starting point for placement.


I have a tricky room for bass and it has really helped me (also using XT32 with the X4000).


since you have two different subs, do it for both of them. If the output is similar it may not be necessary, but if they are vastly different, it is a good idea.


good luck!


Getting a decent response for bass is hard work, but well worth it in the end!

Thanks for the response. A couple of things you said here ring a bell.


A few days before I did the measurements with REW, I was messing with the crossover points in the AVR trying to see if I could get improvement. I remember changing the crossover point to 60 for the mains. And I am not sure I ever changed it back to 80. That may have something to do with the 80Hz null.


So I guess that is going to be my first adjustment and then re-measure with the subs where they were for the first test. I just wonder why that null really mostly shows up on the FR+subs run and not so much on the FL+subs run??? Keeping in mind that the better sub was near the FR speaker.


If that doesn't help, then I will do as suggested and play around with the phase knobs/switches on both subs, one at a time. Then re-run REW and see if that helps.


As for the sub crawl. I have sort of done that using the smaller sub placed in the MLP. But it really was not definitive as I have only very limited places for these subs because of all the other stuff I have in the room and the fact that it is not a dedicated room. So there is going to be a tradeoff. Again what I am ultimately after is the smoothest response I can get at the MLB so that the other listening positions are not so terribly overblown with bass....
 

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ok, good luck! Could be the FR speaker + Subs cancel each other out slightly, but the FL + subs just miss each other. Sometimes even just moving the sub a few inches can make a big difference.


In my MLP, the bass is as good as it will get with my crappy square room (not dedicated, so no bass treatments allowed), but if I sit forward on the couch by a foot or two, there is a huge null and almost no bass. It took me forever to get it to that point.


It is a very noticeable difference though.


Ideally, I would sit in bass awesomeness and my wife in the nulls. She is not a big fan of bass anyway...lol.
 

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Discussion Starter · #8 ·

Quote:
Originally Posted by McStyvie  /t/1523385/first-attempt-at-rew-nee...placement-of-my-subs-in-my-room#post_24506545


ok, good luck! Could be the FR speaker + Subs cancel each other out slightly, but the FL + subs just miss each other. Sometimes even just moving the sub a few inches can make a big difference.


In my MLP, the bass is as good as it will get with my crappy square room (not dedicated, so no bass treatments allowed), but if I sit forward on the couch by a foot or two, there is a huge null and almost no bass. It took me forever to get it to that point.


It is a very noticeable difference though.


Ideally, I would sit in bass awesomeness and my wife in the nulls. She is not a big fan of bass anyway...lol.

I have the same issue regarding the wife. She doesn't really like too much bass. And she always wants to watch a movie perched on the love seat with her legs underneath her. But in order for the bass not to be heavy for her, I pretty much have to turn off the subs. Then it sounds to me like I might as well be listening with the TV speakers.
 

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Get her in a null and you are good to go! May be worth the effort lol
 
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