[K Shep]

I am going to build bass traps out of OC 703.  Cutting 2"x24"x48" panels in 4 equal size triangles.  Then stacking them to build 48" tall traps.  I will place one behind my right speaker, two behind my listening position in each corner, and one behind the speakers next to the window (removing the black foam trap shown in photo).  I will also reduce the number of absorbers in the sitting area. 









Comments are appreciated.

[jtwrace]

I still love that room...I tell / show all my friends.  They are all sooo jealous that you truly have a man cave.  Who would ever think to look up there?  Awesome!

[K Shep]

I still love that room...I tell / show all my friends.  They are all sooo jealous that you truly have a man cave.  Who would ever think to look up there?  Awesome!

Thanks jt,

I picked up 12 sheets of OC 703 today and cut enough panels to build one of the bass traps.  I plan to document the build here.  In the next couple of days I will build the interior form for the trap.  For now here are photos.

[rodge827]

Hey K Shep,
I'm thinking about doing the samething with some 705.
What are you going to use to enclose the bass traps with?
Thanks,
Chris

[K Shep]

I will wrap the stack with acoustic fabric found here: http://www.atsacoustics.com/cat--DIY-Acoustic-Materials--102.html

The issue I have is the material is uneven (my cuts).  So I intend to rip thin masonite, say 1/8"x 1" lengths and adhere them to the front of the trap (interior form).  Then pull the fabric tight against the trap.  I will keep you posted. 

Check out the website above lots of material there.

[rodge827]

Hey K Shep,
I'm familiar with the ATS site. I'll be ordering some bags soon to go over some of the 705 that I have. I had a conversation with Steve Deckert of Decware a while back and he gave me an interesting formula for building bass traps. I didn't write it down and can't remember all that he told me( I suffer from CRS "Can't Rember S#!t" !) . Perhaps a note or a phone call to him may help you out.
Chris
Oops! There goes that CRS again , I'll be buying the fabric bags from Ready Acoustics.

http://www.readyacoustics.com/index.php?main_page=index&cPath=26_11_2

[timind]

I have ordered panels from atsacoustics. They were very quick and efficient all the way through.  Will order more when needed.

[K Shep]

Hey K Shep,
I'm familiar with the ATS site. I'll be ordering some bags soon to go over some of the 705 that I have. I had a conversation with Steve Deckert of Decware a while back and he gave me an interesting formula for building bass traps. I didn't write it down and can't remember all that he told me( I suffer from CRS "Can't Rember S#!t" !) . Perhaps a note or a phone call to him may help you out.
Chris

Thanks rodge,

I will look him up.

[Jeffrey Hedback]

K Shep,

You may find that improving just the corner trapping does not actually do that much in this case (although it can't hurt!).  Your room shape itself creates issues in lower mid, typically a very tough to tame resonance peak in transition of upper bass to lower mid region.  Then the amount of room volume behind your speakers is large enough to create "secondary space coloration"...simply the lower mid is likely to be cloudy.

I would try to address the area right around your left speaker with 4-6" of panels  on adjacent wall and behind (both locations).  I would then create a couple additional "superchunk" traps and wrap all three sides...to place in between the speakers (a la tube trap concept).  Play around with position meaning how close to speakers.  I would start by placing them about 3' behind rear of speaker, listen and adjust.


There's a fine line in a space like this where improving certain issues expose otherwise masked highly discrete problems.  My point in this is for you to make each step in deliberate manner and listen.  You may indeed want to keep most of the absorption you have in place.  Certainly 703 and 705 outperform foam inch per inch, but foam has excellent qualities taming non-normal incident reflections and this could be very helpful in your room.

I look forward to your thoughts and updates.

[bpape]

Hey K Shep,
I'm thinking about doing the samething with some 705.
What are you going to use to enclose the bass traps with?
Thanks,
Chris

In a chunk style absorber or anything else more than 4" thick, 705 isn't going to buy you anything in terms of additional performance.  It'll just cost you more money. The 703 will actually perform better than 705 in that type of arrangement.

Also, if you don't have the space and/or need to save some cash, you can cut 8 triangles from each sheet at 17x17x24" instead of 4 at 24x24x34".  That'll get you 16" of height per 2" thick sheet.

Bryan

[Jeffrey Hedback]

...Brian...very nice tips!

[jtwrace]

...Brian...very nice tips!

He's full of them!!!  Oh, and they work.   

[Nuance]

K Shep,

You may find that improving just the corner trapping does not actually do that much in this case (although it can't hurt!).  Your room shape itself creates issues in lower mid, typically a very tough to tame resonance peak in transition of upper bass to lower mid region.  Then the amount of room volume behind your speakers is large enough to create "secondary space coloration"...simply the lower mid is likely to be cloudy.

I would try to address the area right around your left speaker with 4-6" of panels  on adjacent wall and behind (both locations).  I would then create a couple additional "superchunk" traps and wrap all three sides...to place in between the speakers (a la tube trap concept).  Play around with position meaning how close to speakers.  I would start by placing them about 3' behind rear of speaker, listen and adjust.


There's a fine line in a space like this where improving certain issues expose otherwise masked highly discrete problems.  My point in this is for you to make each step in deliberate manner and listen.  You may indeed want to keep most of the absorption you have in place.  Certainly 703 and 705 outperform foam inch per inch, but foam has excellent qualities taming non-normal incident reflections and this could be very helpful in your room.

I look forward to your thoughts and updates.

He's not only going to add bass traps.  In fact, he's going to do exactly what you said: start with bass traps, see how they improve things, then move on up through the FR, addressing other issues as we go.  The bass traps are needed, as his measurements show a lot of ringing.  After they are completed he'll remeasure and we'll go from there.

Correct me if I am wrong, Kirk.

[Jeffrey Hedback]

Excellent Nuance.  Seems that Kirk is headed toward great improvements. 

[Nuance]

He (we) certainly hope so.  I am also going to request he add diffusion (real diffusion ), perhaps on the top of that back wall (the triangular part).  That will probably be towards the end of the process, though. 

Kirk, way to take the bull by the horns and get to it right away.  I like your initiative bro!  Do keep us posted. 

[K Shep]

Thank you Gentlemen,

Nuance, I tied to post my measurements however I am unable to pull them from my computer?

Jeffrey, I am trying to understand where you recommend the absorption.  I believe you are suggesting placing 2'x4' panels behind the speakers on each side of the wall. Should I place them vertically or horizontally?  I have several panels made, I plan on moving them around this weekend along with placement of the bass traps.

[Vapor Audio]

Any way you could knock out that storage area that's finished off behind the right speaker?  I see the biggest issue you're facing as lack of left/right symmetry.  Without that section there you could then move your speakers back a bit, maybe right about where the ladder comes through the floor ... and also move your chair forward from the back wall, reducing it's reflection effects and decreasing it's boundary gain. 

[K Shep]

Any way you could knock out that storage area that's finished off behind the right speaker?  I see the biggest issue you're facing as lack of left/right symmetry.  Without that section there you could then move your speakers back a bit, maybe right about where the ladder comes through the floor ... and also move your chair forward from the back wall, reducing it's reflection effects and decreasing it's boundary gain.

Or I could just build a new room.  (sarcasm)

I agree however the room was laid out to fit around can lights (the platform in the room is above existing can lights too).  I built the room from scratch in my attic.

[Vapor Audio]

Or I could just build a new room.  (sarcasm)

I agree however the room was laid out to fit around can lights (the platform in the room is above existing can lights too).  I built the room from scratch in my attic.

Cool, so if you did it yourself, is taking that area out not an option?  I'd think it would open up other placement options for you ... and the symmetry would help even out the spatial cues in the time domain, giving you better overall imaging.

[Jeffrey Hedback]

Hi Kirk,

...yes I can hopefully clarify my suggestion.

One the wall immediately adjacent to your left speaker, place a thick absorber (4" would do).  Looks like you may have a 1" panel there now???  Thicker is better.  And do the same behind the left speaker (about 6-12" behind the rear of speaker).

The second suggestion was to create two free-standing triangular absorbers...they would look similar to the GIK Tri-Trap (and in fact those would work very well).  These two would be located behind and between your speakers to offset the rear volume of space.

I'll stay tuned to your progress!