# Bass response from 100 to 300Hz



## aps (Aug 11, 2008)

Folks

My room is 12 ft x 16ft x 10ft (W x L x H) and houses DIY speakers which fire down the length of the room. I have, over the past months, focused on optimising the location for spatial imaging and more recently started to use REW to assess bass response. This process has identified a peak around 35Hz and number of dips at 140, 175, 200 and 300Hz that I’m guessing are room modes.

The folks at the REW forum have helped me use equalisation to address the peak and pointed me to this forum to learn about how to deal with the room modes in the 100 to 300Hz range. So, the current room treatment is limited to some large foam bass traps that straddle the front corners and extend almost to the ceiling. 

My goal, now, is to put in place some proper room treatment to address the 100 to 300Hz range while not destroying the room’s ambience or aesthetic. The room layout supports treatment on the front wall / corners, wall / ceiling boundaries and tri-corners but treatment on the back-wall would be limited in nature. Is this achievable? What treatment is recommended for this range? And where should it be located?

Regards,
APS


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## bpape (Sep 14, 2006)

Where is the seating position in relation to the room length (ear position)? That and being willing to compromise between imaging and bass response in terms of speaker positioning can do a ton to help you - especially if you can't treat behind you on the rear wall.

Taming the rom is as achievable as you're willing to allow it to be in terms of treatment placement, positioning of you and speakers, etc. 

Bryan

Lose the corner foam or move it to the wall/ceiling juntions in the front wall/ceiling junctions. They're really not doing much down low. On the side walls, the foam may or may not be OK for reflections. They'll not help any with SBIR (boundary related bass issues)


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## aps (Aug 11, 2008)

bpape said:


> Where is the seating position in relation to the room length (ear position)? That and being willing to compromise between imaging and bass response in terms of speaker positioning can do a ton to help you - especially if you can't treat behind you on the rear wall.
> 
> Taming the rom is as achievable as you're willing to allow it to be in terms of treatment placement, positioning of you and speakers, etc.
> 
> ...


Bryan

Thanks for the response! The listening position is 10ft from front wall / 6ft from back wall. Also, I’m able to put flat panels against the back wall either side of the venetian blinds (or free standing in front of the blinds) but not in the rear corners. Where would you recommend starting with the room treatment? And what type of room treatment is right for this frequency region given the desire for good performance / aethestics? 

Regards
APS

Edit: Is there a use for the large foam bass traps?


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## bpape (Sep 14, 2006)

First, sorry for the bad message format - not enough coffee... 

I'd start by moving your seating forward maybe 6" or so if possible.

Good chunk style absorbers in the front corners, a couple of thicker panels on stands centered on the rear wall, and side reflection panels would be where I'd start.

Bryan


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## aps (Aug 11, 2008)

bpape said:


> Lose the corner foam or move it to the wall/ceiling juntions in the front wall/ceiling junctions. They're really not doing much down low.


Just re-read this post while in the room. You mean that these panels would be placed in horizontal orientation and placed to straddle the wall-ceiling boundary at the front of the room (as per picture below)? If so, then is there a benefit in doing the same with the back / side wall ceiling boundaries? 



bpape said:


> Good chunk style absorbers in the front corners, a couple of thicker panels on stands centered on the rear wall, and side reflection panels would be where I'd start.
> Bryan


This advice is very helpful. What, specifically, do you mean by "chunk" style absorbers?

Regards
APS


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## bpape (Sep 14, 2006)

Yes. Orient them straddling the wall/ceiling junction. Front would be better if there's space. If not, the rear will still help.

Chunk style absorbers are solid triangular absorbtion. Something like our Tri Traps.

Bryan


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## aps (Aug 11, 2008)

Bryan

Thanks. Wow - your post has openned up this whole new world of "super chunk" traps. What are the respective benefits, though, of a "superchunk" trap versus a flat-panel trap that straddles the corner?

Cheers,
APS


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## bpape (Sep 14, 2006)

Chunks of the same face area and height will have much more overall thickness, which means they reach deeper into the deep bass. 

Also, if you look at a 2'x4'x4" panel, that won't perform as well anyway, the BACK of the panel hits the 2 walls where the chunk style absorber would stop. Then, the panel sticks out another 4" at 45 degrees. So, the chunk works deeper AND takes up less space.

Bryan


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## aps (Aug 11, 2008)

Understand. Is there a design for a frame that can be used to house super chunks that are attached to the wall / ceiling boundary? My thinking, I guess, is to make 4 to 6ft long traps that go horizontal along the front and back wall / ceiling boundaries.

Regards,
APS


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## bpape (Sep 14, 2006)

The easiest way is to just rip a pair of 1x2's at 45 degrees along their length and attach to the wall to hold the corners of the chunks.

 

This is a generic sketch I have showing normal construction for behind a false wall. If you rip both sides as shown on the bottom cleat, it makes a nice finished look. Add a little trim to cover the staples and you're done.

Bryan


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