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Removed sofa, thought I needed more bass trapping

Need some help here with Room Acoustics and Bass Trapping. I removed the sofa in my listening room and in its place put a leather listening chair.

I just assumed that I would need additional room treatments. The sound definitely did get a brighter after removing the sofa. With the new Leather chair and all (reflective), I expected this.

I had 4 bass traps in the room already, in each corner of the room. Jon Rietch states that one can never have too many bass traps??? So I thought I would try building his panel style DIY bass traps to add to my existing traps.

The result is not good sounding. The whole soundstage narrowed, brightened further, and bloom disappeared etc. It was like the lower to mid frequencies diminished. Bass traps improve and define the lower region. That is what my other ones did.

So, maybe I overtreated the room?? In other words, "Did the extra heavy fiberglass insulation in the panels made the room 'acoustically dead' and not lively enough"????

I tried putting all the new panel traps I built on the opposite wall (back wall) from the speakers. At least in multi channel mode (home theater) the result was one of hearing the surround speakers in an unnatural way rather than ambience. In two channel stereo listening, it did not have a profound effect on the sound.

Any ideas where I am going wrong with my thoughts here? The speakers are Maggie 1.6. Maybe the sofa really wasn't absorbing much to begin with? You'd think that all those cushions would have to have tamed the room somehow though.

Hopefully this will generate some lively discussion.

R.
red2
4 responses Add your response
ngjockey
1,042 posts
 

This is a tough question. Obviously a big foam couch is going to absorb mid to high frequency and will affect a room.

Usually, the rear wall and corners is the right place for bass traps.

My research on bass traps is the only effective way to make a bass panel is with membranes or very large tube traps (20 inches or so). The membrane style should only work up to 300 Hz or so and would not make a room brighter. However, the panels may be more reflective than drywall. If you are just using rigid fiberglass panels, by themselves, they would only begin to absorb above 300 Hz and can "deaden" a room. I can email you a couple of "cheap and dirty" DIY membrane trap schematics. After the holidays, I'm gonna try to build something myself.
yioryos's avatar
yioryos
723 posts
 
My good man,where did you move the sofa?Not on the sidewalk I hope!
Sorry I couldn't help myself.
Best
George
red2 OP
79 posts
 
I should make a few clarifications in my message.

First, the sofa was actually a Futon. Are those not mainly constructed of cotton type material?

I believe that the dipole nature of the Maggies does not work well with corner bass traps. As stated earlier, my existing bass traps at the front of the room are about one foot behind the woofer panel itself. The speakers are about 5 feet off the front wall.

They say that the front and rear wall should be different from each other in material construction or absorbtion, diffraction qualities. That is why I thought if I covered the wall at the rear of the room with all these DIY panels, that I may gain something. That said, the rear wall in the room has a "L" shape jog to it. Maybe the lack of an even plane wall at the back already breaks up the sound alot????

Hope that helps clarify some things.

R.
djohnson54
396 posts
 
One thought that occurs to me is that as you absorb more of the bass frequencies, you are changing the balance of the energy in the room. This could indeed sound brighter without and actual increase in the treble energy.

Also, I'm not an expert but the business about not being able to have too many bass traps doesn't sound quite right either.
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