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Asymmetrical Room Treatment

Hi everyone. I have a relatively small room (about 11x15x8). For a variety of reasons I have really only one option as to which orientation to place my speakers (Thiel 2.3), which happens to be against one of the 11' walls. In general everything is great, except for one issue- the room is closed off all around except for an opening into the kitchen/rest of my apartment behind the left speaker. The opening is about 4' wide. I think this is preventing me from getting as good an image as I otherwise would, and I am not sure what the best method to treat this problem is. I recently made some 4" OC-703 bass traps, and have placed one of them across the corner behind the right speaker (which has a wall), with another trap directly next to it along the front wall.

My suspicion is that the best way to go would be to treat the area with as much low, or just broadband, absorption as possible behind the right speaker (which has a wall behind it) to try and balance things out. Any thoughts on this issue? I haven't been able to find any information addressing this specific room problem! Thanks.
chrisar

Showing 5 responses by zmanastronomy

zmanastronomy's avatar
zmanastronomy
738 posts
 
The drapes will only dampen the very high frequencies at best. (20khz+)
Get some absorbers behind you and infront of the window.
I would also pull the bass trap out of the corner thats behind you.

You may not realize it because you don't have your first reflections dampened in the room. But trapping the rear corners will kill the soundstage of a room.
I would take the rear bass trap and put it in the same corner behind the right speaker with the other bass trap and that will kill any bass node that is behind your speakers.

The open wall to the left is allowing the bass to be dampened by escaping the room.

This will help in the bass department, but the imaging and soundstage will only be good with treatments in at least the first reflection points through out the room.
It's only then that you will be able to realize the potentual of your soundstage and imaging and ballance out the system.

My best freind has the same problem as you.
He's treated the room on the sides and behind his seating position and the soundstage is very ballanced.

Hope this helps.
John
zmanastronomy's avatar
zmanastronomy
738 posts
 
Hi Chris.
Putting some 4 inch absorbers in fromt of the window will definatly be a good choise.

They will act as bass traps and controle the mid and high reflections.

I found when you treat the rear corners of a room (behind the listening chair) it seems to kill the sound stage.
You must keep the rear corners lively and work on the first reflection points.

The foam you are useing is not doing much to absorb lower highs and lower.

The compressed fiberglass in the two inch size does a much better job.

Go to my system and read how to get the room treatment really cheap.

It's a do DIY set and you can do a room very well with minimum yen.

Hope this helps.
John
zmanastronomy's avatar
zmanastronomy
738 posts
 
Kevin.
The bass wave doesn't go right through the glass because it's see through.
It reflects back into the room because of solidity of the window.
Now, if the window was open then it would escape into the outdoors.
It's obviouse you have spoken above my comprehention, but I know for a fact, not just assuming, that if you dampen the rear corners it will kill the soundstage if the first reflections are treated.

Been there done that.
zmanastronomy's avatar
zmanastronomy
738 posts
 
Kevin.

I've often wondered about soundstage depth and width.
Since it all happens at the ear, how does the width of a room and depth of a room affect what happens at your ear ?

I can hear or perhaps preceive that a kettle drum is thirty feet behind my speakers when in fact, the wall is only three feet behind my speakers.

Is it the illusion of depth from reverberation in the mixing of the music ?

I have some Mapleshade CD's that doesn't go through the mixer, but goes from the mike strait to two track and the depth goes well beyond my wall.

If you can explain this to me it would help me understand the three dim. soundstage much better.

John
zmanastronomy's avatar
zmanastronomy
738 posts
 
Ckoffend.

I'm sure he's talking about a 4" panel.

Also, it sounds like you're putting together a really nice room.
I would stress that the 15 ft. space behind you should also be treated in some mannor.
Stand at your listening position and clap your hands, do you here any echoe ? If not you are good to go.
If so, you need to dampen the area behind you.

15 ft. is a long distance and the reflections at 15 ft really turnes into 30 ft. by the time it arrives at your chair. That's a huge timing gap.

Anouther point I'd like to make is that if you treat a room one wall at a time and you sit to listen to the results, if you make a mistake and over dampen the room, you will immediatly know that you went to far. Your sound stage will collaps.

It sounds like the combo of absorbtion and deflection, your going to have a great sounding room.

There's nothing in the electronics world that can give the upgrade that a well treated room can.
If someone is reading this and never heard a treated room, then you need to treat your room.
It is the most bang for your buck in audio.
Have fun.
John
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