[krum]

I have recently read a number of the posts on this cite and just registered with the hopes of gaining some insights.  I finished a free-standing room in my basement which is currently being used for two-channel audio and will also be used for a surround system.  The first issue I am trying to deal with is that the sound tends to lean towards my left.  

The room is basically rectangular with a width of 13 feet, lenght of slightly over 21 feet and height of just under 7 and 1/2 feet.  The speakers are set up the same distance from the wall behind them and the side walls.  I wonder if any of the following room characteristics may result in what I am hearing?  And, if so, if anyone has any suggestions,

1.  On the side wall to my right the final four feet of the room are open.   This opening is behind me.  The opening is into a 5 x 7 landing way where the stairs come down (the stairs are behind the rear wall).  I have the option of extended this side wall and adding a door leading into the landing way; thus, closing up these final four feet.  Other than this opening the room is completely enclosed.

2.   Along the right side of the room I had to box in the support beam which runs the lenght of the room.  Thus, the height along the right wall is 9 inches lower than the remainder of the room.  This decrease in the height is for approximately 15 inches (width wise).  The support beam has two metal support posts a few inches from the side wall the first of which is about 5and 1/2 feet from the front wall and the second is about 14 feet from the front wall.    

3.  I do have a door on the left side wall about 1 and 1/2 feet from the wall behind the speakers.  This door was added at the request of a building inspector but can be removed as another inspector who actually did the inspection said it was not needed.  If the door is removed the opening would simply be replaced with drywall.

The room is free standing meaning I can get behing all walls except the wall behind my seating position is this is where the stairs come down into the basement.  Any suggestions will be truly appreciated.  Both in terms of what may be causing my perceived symmetry issue and also in terms of acoustical treatments.  Regards,

Krum

[Red Dragon Audio]

do this:

Swap the left and right speakers.  Does it still "lean" left?  If so then try the next step...

Swap the speaker channel outputs on the back of your amp so the left speaker is powered by the right channel and the right speaker by the left channel.  Does it still lean left?  If so, then proceed to next step...

Swap the Left/Right inputs of your amp or preamp or source and so on.

there might be a place in the chain of components that has a weaker output than the other channel.

If after trying all these methods it still leans left.  I'd say get rid of the system as it's a good-for-nothing-liberal!    

all jokes aside...

Maybe you just check your balance control if you have one and lean it right so to speak.

Your room doesn't seem like it would be enough of a culprit to make the sound lean left so much.  You've got pretty much parallel walls in front of your listening position and just to the sides.

[youngho]

Krum:

I'm sure profound and useful advice will follow shortly. Pardon my trivial and ineffectual thoughts.

Just out of curiosity, is there a reason why you wouldn't be able to rotate your setup by 90 degrees and to have the speakers set up along one of the long walls? The ceiling currently being lower on the right side does mess things up a bit.

I assume you've already looked here for basic guidelines regarding speaker positioning for your anticipated surround sound system:
http://www.dolby.com/consumer/home_entertainment/roomlayout.html

You might essentially consider the opening to the landing as a very, very good absorber for all frequencies and the door an absorber of low frequencies. With the free standing room, you may be able to use fiberglass absorption behind the walls to assist in low frequency absorption?

I'd suggest trying this just for fun as a start:

1. Face the couch toward the wall with the support beam and posts, near the center of the room or slightly pulled away from the wall with the support beams and posts.

2. Position the right speaker just to the left of the right support post, so about ~8 from the nearest side wall and, say, a foot from the rear wall. Position the left speaker about three feet right of the left support post, so about ~8 from the nearest wall and, say, a foot from the rear wall. This will put the speakers about 12 feet apart with you as the point of an equilateral triangle. This should help reduce the effects of side wall reflections (the side walls are now much further apart).

3. Place some mix of diffusors and absorbers behind the listening position.

Alternatively, flip these suggestions around 180 degrees if you think you might be able to mount surrounds from the support beam at the relevant angles...

Young-Ho

[krum]

Thanks Ryan.  

I actually swapped the speaker cables, right to left and left to right, with no change--would this not eliminate the possibility of the problem coming from the chain of components?  I did the swap at the speaker not at the amp.  Of course another possibility is that my hearing is going bad.

(Of course to get rid of the good-for-nothing-liberal system I can simply put the speakers at the other end of the room, turn around the sofa and have a system leaning to the right).

Krum

[krum]

Young-Ho,

Thanks for the input.  I thought about rotating my setup by 90 degrees but that would leave me with little room behind the speakers and I do wonder how that may impact the imaging?

Will fiberglass absorption work behind the drywall?  

Krum

[youngho]

Krum, you might try rotating the setup for reasons of symmetry, even if you're not able to get a significant amount of room behind the speaker. In theory, having the speaker close to the back wall increases excitement of certain standing waves, though careful seat positioning may ameliorate this, hence my suggestion of having the seats pulled back slightly from midway, perhaps as much as 2/3 back from the front. If you're planning to set up a home theater system, you may end up redirecting low bass to the subwoofer(s), anyway. Worst case, you try it, say "That Young-Ho is really a fool," and change it back. I think you might be pleasantly surprised, though.

My understanding is that drywall kind of lets the bass pass through relatively easily, but I assume that there's a concrete foundation or something else fairly rigid and massive on the other side of the dry wall, so a significant amount of fiberglass absorption behind the drywall will help "trap" bass passing through and back.

Incidentally, it might be helpful to the smarter folks to know what kind of speakers  you are currently using for stereo and considering for surround.

Young-Ho

[krum]

Young-Ho,

Once I have a chance I will try the 90 degree rotation--I am open to all suggestions.  My speakers are sonus faber conceto home (I have had them for a while but moved them downstairs as they needed to be out of the upstairs area).  I do like the speakers but may upgrade at some point--however, after a little reading on this cite it seems logical to first deal with room acoustics before considering any upgrade possibilities.  Thanks for you continued thoughts,

krum

[woodsyi]

krum,

Welcome to the forum.  I have a room dimension very similar to you, 16x22x7.  I also have a soffit (covering duct) about where you have it.  I have an opening to the left leading to a landing for stairs.  Unlike yours, three sides of mine abut cinderblock with wooden panel and insulation in between.  My left wall is only a panel separating from the laundry/utility room.   I used to have my speakers along a long wall and listen from the opposite wall. I have since changed to more traditional orientation of having the  speakers against the short wall.  I have better balance since it's more symetric this way.  The wide set up could not be centered and created imaging as well as bass loading issues.  If you plan to go 7.1 you will need to stay the way you are.  I don't know why you have your listening postion so far back.  It may be better to get within 8' of you speakers if they are 8' apart.  I tend to think it's your equipment that has the liberal lean but check your ears by going between the speakers and listening out with the speakers.  Otherwise, may be you have different spacing behind the drywall thats loading bass off center.

[Ethan Winer]

Krum,

> I thought about rotating my setup by 90 degrees <

Don't do it. You want the speakers firing the long way down the room.

> Will fiberglass absorption work behind the drywall? <

Not nearly as well as if it's inside the room!

That said, all walls should have fiberglass inside them to reduce resonance. Or behind if the wall has sheet rock on only one side of the studs. But you also need bass trapping inside the room.

I'm not really sure what would cause an imbalance, since it sounds like the left and right sides of the room are the same in front of you, which is where it matters most. Do you have a large piece of plywood or sheet rock you can put over the opening, just as a test?

--Ethan

[Red Dragon Audio]

Thanks Ryan.  

I actually swapped the speaker cables, right to left and left to right, with no change--would this not eliminate the possibility of the problem coming from the chain of components?  I did the swap at the speaker not at the amp.  Of course another possibility is that my hearing is going bad.

yes.  

(Of course to get rid of the good-for-nothing-liberal system I can simply put the speakers at the other end of the room, turn around the sofa and have a system leaning to the right).

Krum

but then it's leaning right and it will be a gun toting, bible pushing, right wing nutjob!

[ctviggen]

You didn't describe what your system looks like.  In my system, I have a RPTV on the left and a rack on the right.  My system also leans a bit to the left (in the sense that I have to sit slightly off center).  However, when I take two microtraps and cover my RPTV and in particular my rack (which has a lot of componentry), the "left leaning" of the system is dramatically lessened or eliminated.

[krum]

Thanks to all for the various comments.  As a true novice this cite is an excellent tool to learn with.  A bit more information.  My speakears are about 4 and 1/2 feet from the wall behind them and 2 and 1/2 feet from the side walls.  The distance between the speakers is about 8 feet and I sit about 8 feet from the speakers.  I have a 36" sony trinitron on a tv stand/rack between the speakers.  

All four walls are drywalled and except for the wall behind me the drywall is only on the room side.  All four walls are insulated with fiberglass insulation (R-13, 3 and 1/2").  On the outside of the left side wall I have between 3 and 5 feet  between that wall and the poured concrete; on the other side of the right side wall I have over 20 feet before the concrete.  I would not of thought this would cause a problem but after reading some of the posts I wonder--any thoughts?  Thanks again,

Krum

[Ethan Winer]

Krum,

> On the outside of the left side wall I have between 3 and 5 feet between that wall and the poured concrete; on the other side of the right side wall I have over 20 feet before the concrete. I would not of thought this would cause a problem but after reading some of the posts I wonder--any thoughts? <

I can't imagine the different distances between the interior and outer walls would make a difference. That might affect the lowest frequencies a tiny bit, but imaging involves frequencies above about 300 Hz.

--Ethan

[MaxCast]

Try some of Ethan's traps on the first reflection points on the l&r walls and stand a couple in front of the system.

[krum]

Thanks Ethan--I will pick up some plywood and try it in my opening to see if it helps.  

Krum