Comb Filtering, 2 front left, and 2 front right speakers a bad idea?

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Beatmatcher247

Full Audioholic
I have a PSB Synchrony One 5.1 setup and really love the sound of them. I primarily listen use it to listen to music in 2 channel mode and watch the occasional movie on it.

I love the sound of my music so much in 2-channel mode and just want more of what I like about them instead of pushing these beyond their limits. Is putting another set of towers next to each other a horrible idea because of comb filtering? I don't want to drop a ton of scratch to find out the hard way.

I have these pretty high-sitting leather couches with high backs on them and when I lean my head in about a foot it sounds a lot better, in volume, clarity, and imaging. If I could get that sound in my sitting position I would be satisfied and not feel left wanting more when I listen to my music.

I've talked with the guy that sold them to me and he recommends angling them up towards my ear a little more. I am not sure how to accomplish that without them becoming easy to knock over. At first I thought it was just that I didn't have them forward far enough, but no matter how much I move them forward its the same deal. It always sounds better with my head leaned in forward about 12".

I've got a stairway going up in front of my sitting position by about 2' and one going down directly to my right from the seating position. I'm trying to determine what's causing more of the problem here. My furnature, my speaker position, or my room. Is the furnature making a mess of the waves around my head when the sound hits them? The tweeters on my speakers sit about 8" below my ear's level... do I need low-rider furnature to make these sound as good as they can?

Just looking for some ideas on what I've got going here from someone who's experienced something similar.
 
gene

gene

Audioholics Master Chief
Administrator
You are better off running a 5.1 or 7.1 system in PLIIx Music Mode or 7 Channel Stereo mode (with the center and surrounds turned down to 30-40% of front channels).

Alternatively, sell your front speakers and buy a model that will play louder instead.

The issue of placing speakers side by side like that is more with acoustical interference than comb filtering.
 
Swerd

Swerd

Audioholic Warlord
The issue of placing speakers side by side like that is more with acoustical interference than comb filtering.
Whether you call it acoustical interference or comb filtering (gene is technically correct), two speakers side-by-side instead of one can cause problems and are not likely to solve your problem. Even if it could help, it would cost a lot, and depending on your receiver or amp, two speakers per channel would be hard to drive.

Is your sofa backed up against a wall behind it? This also can create acoustic interference. If there is room to work with, try moving your sofa a little forward or a little back from where it is now.

Try moving your front Left & Right front speakers a little forwards or backwards, relative to the wall behind them.

Try putting a pillow behind your back to keep your head a bit in front of the sofa back.
 
B

Beatmatcher247

Full Audioholic
Sofa is not backed up against the wall. I've tried moving both the sofa and the speakers forwards and backwards to know improvement. Same issue, always sounds louder, clearer, and better with my head leaned in a foot. So confused.

Thanks Gene. It sounds much better in 2-channel at least to my ears.
 
S

shadyJ

Speaker of the House
Staff member
It sounds like reflection from the couch is messing up the sound. I wonder if room correction software could help that if the only measurement position was taken from your typical ear position against the couch. Also, acoustic absorption pads on the walls behind the speakers might work to reduce some of the reflection you are getting at your ears on the couch, however I don't think that would do the trick entirely. just a couple ideas...
 
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Beatmatcher247

Full Audioholic
Think I'm going to swap the couch out for a plain old kitchen chair and see if I'm still having the same issue. Then I guess the problem would lie with my furniture... really did not anticipate my furniture being a problem in my theater room.
 
3db

3db

Audioholic Slumlord
Think I'm going to swap the couch out for a plain old kitchen chair and see if I'm still having the same issue. Then I guess the problem would lie with my furniture... really did not anticipate my furniture being a problem in my theater room.
Let us know how you make out with this one. I had a similar experience in another house of mine with a beat up old lazy boy love seat we had.
 
lsiberian

lsiberian

Audioholic Overlord
Think I'm going to swap the couch out for a plain old kitchen chair and see if I'm still having the same issue. Then I guess the problem would lie with my furniture... really did not anticipate my furniture being a problem in my theater room.
I wouldn't expect major issues from furniture it sounds like you need rear wall treatment. Leaning forward would reduce backwall reflections which can cause cancellations with the sound coming forward. GIK acoustics offers artistic panels that might be worth a look.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
It always sounds better with my head leaned in forward about 12"...

...do I need low-rider furnature to make these sound as good as they can?
Sounds like a plan to me.:D

I love lying on my chase lounger when I listen to music and watch movies - great sound, comfortable, and relaxing.:D
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Alternatively, sell your front speakers and buy a model that will play louder instead.
Gene, Beatmatcher just purchased his $5K Synchony Ones like a few months ago!:eek:
 
3db

3db

Audioholic Slumlord
There is something you should know. Hearing damage occurs much faster on a clean system than one that shows signs of distortion for the simple fact that loud clean sound doesn't irritate the ears. This lack of irriatation encourages the listener to increase the volume levels to the point where hearing damage becomes prevalent at a much quicker rate. A system that distorts sends out sound that is irritating so we tend to turn the volume down to lessen the effect. That being said, how big is this room and how loud do you want to play them? Have you measured the output with a SPL?
 
just-some-guy

just-some-guy

Audioholic Field Marshall
I wouldn't expect major issues from furniture
i disagree. i was at zambonies house for a g2g, mark seaton was also there.
john/zambonie and i were talking about his high back leather chairs.
he said that while tuning the system, they were having some real issues.
they eventually found that the sound was bouncing of the backs of the chairs.

i predict this is why the OP has better sound when leaning forward.
i believe that cloth chairs and/or low back would clear up this problem.
though i do not "know". i bought low back chairs.

as always = ymmv
 
Pyrrho

Pyrrho

Audioholic Ninja
...

Alternatively, sell your front speakers and buy a model that will play louder instead.
...
This is what you should do if you require louder than your current speakers can manage. (This is assuming that the volume limitation is caused by the speakers instead of something else, like a low powered amplifier.)

Of course, there is also the issue of how loud we are talking about, as very loud sounds do permanent damage to hearing, often only being observed years later when it is too late to do anything about it.
 
Pyrrho

Pyrrho

Audioholic Ninja
Sofa is not backed up against the wall. I've tried moving both the sofa and the speakers forwards and backwards to know improvement. Same issue, always sounds louder, clearer, and better with my head leaned in a foot. So confused.

Thanks Gene. It sounds much better in 2-channel at least to my ears.
It sounds like reflection from the couch is messing up the sound. I wonder if room correction software could help that if the only measurement position was taken from your typical ear position against the couch. Also, acoustic absorption pads on the walls behind the speakers might work to reduce some of the reflection you are getting at your ears on the couch, however I don't think that would do the trick entirely. just a couple ideas...
There is another possibility. When leaning forward, most likely, your head is not only moved forward, but also lower. If the speakers are not high enough, that lowering will improve the sound. With most speakers, the tweeters should be near or at about ear level. Many people have their speakers at the wrong height for optimal sound.
 
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Beatmatcher247

Full Audioholic
Me and a friend are going to try a few different things and take some measurements with some various furniture setups. I'm sure I'm well into the serious hearing damage threshold when I run these at 0dB.

I used to listen to it at -11db on my marantz av7005 but the speakers don't show any signs of distortion all the way up to 0dB... i've never tried it that loud before and that is way way way plenty loud for me. -11dB was my old limit because the speakers would start to sound a little strained before they were broken in, now I'm good to go on volume. That is way more than I need. I only listen at those volumes for like when my favorite guitar solo part of the song kicks in lol. Instrumental section of All That Remains, the fall of ideals album, track 04 for example.

Now to work out the furniture/room problem for better imaging and clarity. I got to resolve this before my posture starts to make me look like a question mark. We're going to finally do some crawling for bass too with my subwoofers. I need a second set of hands to move those around.
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
I probably sound like a whimp, but when I listen to a new song/CD, I would measure the Max SPL of each song and make sure that it is not >85dBA.:eek:

It seems like 86dBA is just very loud to me.:D

That digital SPL meter is always laying around.:D
 
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