another bass trap question...

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pikingrin

pikingrin

what is this?
Alright, I have read through the threads I found in my search here, read and printed out ethan winer's site that everyone raves about (which I can definitely understand - great site), and still my question has not been answered... I am planning my next investment - homemade bass traps - and have read into it, even bought a book (home recording for musicians for dummies) in hopes of getting good layouts of how bass traps should be built. I understand why they should be air-tight, but in my book it mentions the thickness of the front panel on the trap. It says something about the relation to the thickness of the front panel and the frequencies affected. Does anyone have a clue about this? I am a single-man-band, record and mix in the same (small....CRAMPED) room, and I would like to find out if anyone has experimented with different setups, and possibly the most effective for this situation. If anyone has any ideas or info, please fill me in!

Thank you in advance, because for me (maybe I'm not getting the "big picture") it's a brick wall that I've been ramming my head into for a while... :confused: :confused: :confused: :confused:
 
Airtight? Hmmmm. Maybe I did something wrong.

Anyway, here is what I did.

Got a bunch of 2'X4' 703 panels.

Got some cheap muslin fabric - dyed it blue for fun.

Cut the muslin to about 8 inches bigger on all sides than the 703.

Stretched the fabric slightly over the front of the 703, then used spray adhesive on the sides and around the edge of the back, and wrapped the fabric around.

Then I built a frame out of 1X4 pine with an interior dimension of 2X4.

Finally, I pressed the fabric wrapped 703 into the frame.

I'll even post some pics in a few.

Simple and cheap.

:D
 
the front.....
 

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The back and side - I could of stained the wood and made them "prettier" I guess....
 

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Does that work good taming the beast of the bass??? :D

I have just read that it was "better" to build it out of solid wood, with the rigid fiberglass (or other comparable) filling inside, airtight. The particular article that I am choosing to go by states "The most common placement for bass traps is in the corners behind you when you're sitting a your mixer... 1/4" or 1/8" plywood thickness (for the front panels in the diagram of the plans) depends on the frequencies that you want to trap." ("Home Recording for Musicians for Dummies" - Jeff Strong, copyright 2002.blah.blah...) ;)

Do these do what they are supposed to? Do they "trap" the bass, and prevent standing waves?

Those look easy enough to build, easier than the plans I have anyway... ;)
 
pikingrin said:
Does that work good taming the beast of the bass??? :D

I have just read that it was "better" to build it out of solid wood, with the rigid fiberglass (or other comparable) filling inside, airtight. The particular article that I am choosing to go by states "The most common placement for bass traps is in the corners behind you when you're sitting a your mixer... 1/4" or 1/8" plywood thickness (for the front panels in the diagram of the plans) depends on the frequencies that you want to trap." ("Home Recording for Musicians for Dummies" - Jeff Strong, copyright 2002.blah.blah...) ;)

Is this outdated info? I am in a room approximately 10x12, maybe a little bigger, and there is no sound treatment whatsoever. :eek: I am in the process of acquiring the materials for my other panels, but for some reason feel the need to focus on bass traps...

The 703 that you are using is just sheets of rigid fiberglass, right? Oh, crap... this is confusing... :confused: :( The concept is understandable, but somehow I am confused on the easiest way to achieve results...

AAAAAHHHH!!!! :( :(
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Jeff Strongs are not true bass traps - they are high frequency absorbers/reflectors (depending on which side is faced out). As far as I know, bass traps are not supposed to be backed with plywood.

703 is Owens Corning rigid fiberglass.

:D
 
NL5 said:
Jeff Strongs are not true bass traps - they are high frequency absorbers/reflectors (depending on which side is faced out). As far as I know, bass traps are not supposed to be backed with plywood.
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Yeah, but he also has plans for seperate bass traps which are essentially the same thing, but with plywood on all sides. Essentially a plywood box, 2x4ft, filled with sound absorbent material.

But, like I said, I'm off to home depot to get this stuff! It is cheap enough to be worth a try!

Thanks for all of your help! :D
 
NL5, what did you end up spending for you 2'X4' 703 panels each?

Just trying to get a idea of how much I'll be spending if I built...say 8-10 of them...
 
Zetajazz44 said:
NL5, what did you end up spending for you 2'X4' 703 panels each?

Just trying to get a idea of how much I'll be spending if I built...say 8-10 of them...
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I spent about $200 for 6 of them. I still have enough fabric to do abot 4 more. I figure it will be just about $300 (total) for 10. Mine are 4" thick BTW.
 
NL5 said:
I spent about $200 for 6 of them. I still have enough fabric to do abot 4 more. I figure it will be just about $300 (total) for 10. Mine are 4" thick BTW.
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Thanks! So I guess I'm looking at about $30 each for the 4"... Not as bad as I was thinking...
 
NL5 said:
I just checked out Jeff Strongs site -

http://www.jeffstrong.com/basstrap.html

He notes that he "modified" Ethan Winers plans by adding the plywood skin.

Not sure if that's an improvement or not.
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Well, there's only one way to find out, right? If it's only $200 to do 6 of these bad dogs, then I'll build 2 that are completely enclosed and let you know what the difference is. ;)
 
My understanding with Bass traps is that you want the soundwaves to pass through the medium into the air space. So there is no need to put a backing apart from cloth for fibre containment on these traps.

Here's another link to check out! :)

Go to Homespun Studio and check out traps and absorbers from there!


http://www.hp-h.com/p/hapicmpur/index.htm
 
I did almost exactly the same thing as NL5, except:

mine are 2' wide x 6' tall, and made from 1"x6" pine (6" deep).

I could not afford to have 703 shipped in, so I filled mine with paper-backed R19 fiberglass. I stapled the fabric over the front and around the back edge.

To substitute for the 703 I had to try this sound deadening fiber board stuff called homasote, best I could do in my town on my budget. It's not solid like wood, but not airy like fiberglass. I mounted these on the back of the panels using 3 inch standoffs so that there is an air space between the board and the paper backing on the R19.

I placed them in corners and at random points aroudn the room.

My understanding of breaking up bass waves is that they will pass right through fabric and loose fiberglass, both coming from the speaker and reflecting from the walls. Hence the more solid-ish board (or the 703) on the rear of the panels, so that the bass wont just bounce back right thru the panel.

So far my crappy basement room is now sounding a lot tighter and a lot more honest. Best I can do with these weapons!

Each panel cost me $25 to build.
 
Gorty said:
My understanding with Bass traps is that you want the soundwaves to pass through the medium into the air space. So there is no need to put a backing apart from cloth for fibre containment on these traps.

Here's another link to check out! :)

Go to Homespun Studio and check out traps and absorbers from there!


http://www.hp-h.com/p/hapicmpur/index.htm
Click to expand...
So are you saying, in the case of putting these in the corners, it would be better to have NL's design, with nothing but the fabric and the fiberglass? If that is the case, then I should just need these (easier to build anyway) to treat my room. That would be a good thing! :D I think in the long run, I want to build some of those reflector panels too (mr. strongs design). http://www.jeffstrong.com/gobos.html
At least 3 so I can place them to where it would box off a small area for vocals with the absorbant side, and maybe make an acoustic a little brighter with the reflective side. Any ideas or opinions on that?
 
pikingrin said:
So are you saying, in the case of putting these in the corners, it would be better to have NL's design, with nothing but the fabric and the fiberglass? If that is the case, then I should just need these (easier to build anyway) to treat my room.
Click to expand...

That is what I am constructing as we speak. I am no acoustic engineer but from everything that I have read this is what I understand as being the most effective for us "Do It Yourselfers" to build and get the best results. :)
 
You guys are confusing a few concepts. The original post was asking about a "Panel Trap" which uses a piece of plywood over the front and the entire trap works as an air spring to absorb low frequencies. It's basically the opposite of a speaker.

The other traps are simple absorbers in which case it is best not to put wood on the edges because you reduce the effectiveness of the absorption by about 25%. Sound hitting the edges is a big part of the absorption. These traps should also have an airgap between them and the wall for maximum low end absorption.

I have never built a panel trap but since the barrier needs to move I would think you would use 1/8" or 1/4" plywood. The tension can be adjusted with the screws you use to attach the panel. The usual method of tuning a panel trap is to attach a piezo pickup and tuner to the panel and play some low tones through your monitor. The tuner will tell you at what freq the trap is resonating the most. You can then tune it by adjusting the screws until you are in the range you want.

The cheapest and easiest bass trap is made by using 705FRK with foil backing. Place the 705 in the corners with the foil facing out. Just use some 1"x1/2" wood to build a picture frame that attaches to the back (not sides) of the 705 and can be used to attach fabric and hang on the wall.

There is a lot more info in the Studio Building forum.
 
So all this talk of building a wooden frame around a piece of rigid fiberglass insulation is NOT the way to go...

...but rather just cover your rigid fiberglass insulation in fabric, and you're done... Right?
 
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