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-   -   How I built my bass traps... (

matucha 1st October 2006 10:01 AM

thanks cooge

I'm almost finished with the side "panels" and now I'm going to work on polys in front. There are construction problems I need to solve, because making computer model doesn't always tlanslate directly in reality hidz

Poplab Studios 1st October 2006 10:26 AM

they look great man!kfhkh kfhkh kfhkh

milza 1st October 2006 12:18 PM

@matucha: really nice looking room. why the wood-panel in front of the 703? which effect does it have?

tomdarude 1st October 2006 12:31 PM

my guess:
his plan is to reflect & retain some of the high-freq´s while still absorbing
mid & lower mid freq´s......despite on ear-level (sitting) where you want a RFZ (reflexion free zone) I right??

guys, down to what center-freq. do you think a plain 18mm OSB-board/hardwood board would reflect ?? any idea...guesses?


milza 1st October 2006 12:46 PM

danke tom. ich werde diese bauweise definitiv auf meinen studioraum ummüntzendiddlydoo

i got a second and hopefully last question: why the plastic-bags (don´t know the english name for it) on the 703?

matucha 1st October 2006 12:48 PM

tomdarude > exactly --- it is kind of experiment, will see how it is going to work. I've completed just one side up to this moment and the other is just bare construction with that red fabric covered panel attached to it... and it looks like it is going to work ;-)

Also these wood panels work as membranes, they are thick (18mm) so they should get the low bass... possibly ;-)... I tried to touch them when running bass sine sweep and what makes me happy is that each of the field is vibrating at different freq.... ie there is some "broad-band" absorbtion happening.

> OSBs should reflect very well
- it is heavier than wood is
- it has slightly non consistent surface, but I doubt it will have any diffusion effect

matucha 1st October 2006 12:51 PM

The plastic bags cover the rockwool just for the safety reasons (and you can manipulate it without wearing gloves). I saw that in every studio construction I've been to. I was told that it doesn't affect the absobtion a lot... and for basstrap use I think it should be acousticaly "transparent".

milza 1st October 2006 12:59 PM

i talked with a contruction manager i´m working with in my company about the german it´s called trittschall-dämmung as iám right. he said it isn´t as dangerous as a lot of people say. but you are: when you work in your studio every day, it would be dangerous don´t covering them from the air so that you breath them in.
your contruction is not only for audio-treatment, it looks really nice and professional so clients would be proud to work in ithowdy

djui5 1st October 2006 07:56 PM

Those look amazing cojo kfhkh

Cojo 1st October 2006 08:13 PM


I'm suprised myself! heh I've learned a lot during the construction so the next ones I build would probably be even better. I really wanted the wooden frame but if I knew the were going to be so heavy I don't know... gooof

Thanks everyone for your support. It has been a pleasure to read! kfhkh


matucha 1st October 2006 11:11 PM

IMHO you can't make it lighter than "wood", ok some less dense wood is lighter, but you can easily damage the surface and the edges. OSB for ex. isn't light at all... it was no fun puting these osb frames on the wall in 2 persons.

And yep, cojo, you have classy lokin traps kfhkh

Cojo 1st October 2006 11:53 PM

Yeah I can imagine... those looks really heavy as well but I think you gonna get a nice place when you're ready! kfhkh

Keep the hammer going! hittt


matucha 2nd October 2006 01:26 PM

1 Attachment(s)
well, this is the end of my hijack of this thread... current situation just after moving in and making temporary setup for testing and getting used --- will continue in a new thread abduction

rolo95 3rd October 2006 05:46 AM

Nice traps
what hapened with the graphs... ?

cant see them...
did you read my post on the freq response of mainstream nearfields.. ?


Cojo 3rd October 2006 08:24 AM


I don't know what happened... it will not show after I've downloaded it? I'll give it a new try.

Yes I read your post about the freq responce. The problem frequences I've experienced when I have mixed in my room is those around 60Hz - 120Hz. That's why I didn't go so high as 300Hz but you're probably right, it may be a good idea! kfhkh

I have a Blue sky monitor one system and I know they can't play 20Hz but I really wanted to see it for my self! diddlydoo heh


Cojo 3rd October 2006 08:28 AM

Sorry It will not show!?? grrr


I've found this EFT program and I'll try to send some plots when I've figured out how to use it! kfhkh


Cojo 3rd October 2006 11:20 AM

1 Attachment(s)
Ok, lets see if this works...


This is the low freq response with no treat.

Cojo 3rd October 2006 11:23 AM

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...and here it is with just four traps (one in each front corner and two against the front wall).

tubedude 3rd October 2006 11:41 AM

That looks rather cool, yet simple. Has me thinking about how I'm going to do it.
How would you go about amking those eliptical wooden deals behind the speakers though? Thats tricky stuff.

Tomer1 3rd October 2006 02:45 PM

If your planing on using backing (I choosed to use MDF for my Gobo's backing),
Leaving an air tight space equal to the thinckess of the isolation between the isolation and the backing will give you much better results in terms of how low your broadband panel "can go".

for example:
Cloth - 6` 703 - 6` Space - Backing

Cojo 3rd October 2006 05:10 PM

1 Attachment(s)
Ok guys...

...the last picture! Here they are at place. I put them at the front wall and one at each front corner. After some testing this position seems to give the best overall response with just four traps. The next thing now is to get a small cloud up and some damping on the side walls.

Thanks for your interest!



keithrt99 10th October 2006 01:23 AM

how much did it cost to make these traps? i'm looking into making some, or buying some from GIK. Which would be cheaper? I figure i will build gobo style stands for the gik's if i bought them.

Also, where can i get 703 in northern california? do they sell it at home depot or do i need to order it online?

matucha 10th October 2006 02:05 AM

The ones that Cojo made should be quite inexpensive, when I calculated all the money I payed to build mine, it was around $200 for one panel. Seems like nothing...

SMC Productions 10th October 2006 02:27 AM

Well, don't keep it a secret. Link please? cooge

Cojo 10th October 2006 09:33 AM


The cost/trap was 34 euros.


matucha 10th October 2006 09:58 AM

Just trying to figure it out. There are ways how to bend plywood to various shapes (for ex. some chairs are made from that). But I'm going to just force a thin flat plywood into a frame of some kind... with some bulkheads... and for the fabric covered parts I'm going to use perforated sololit with high perforation %, that should act like almost uncovered wool.

Will see, I'm about to start building it...

orange 10th October 2006 10:20 AM

I would have thought that thin plywood would have been easy to bend to that kind of shape. I wonder if you might need some kind of dampening material stuck behind them (like you get inside a car door or hood). They might vibrate a bit at their resonant frequency.

FWIW you can get flexible MDF (it has parallel grooves cut into it) that you can easily bend into cylinders etc.

matucha 10th October 2006 11:03 AM

That's why I have two packages of rockwool in the yard waiting to be part of it ;-).

I hope it is going to bend well. I also saw this MDF, but I prefer to have the "same" material on the front wall as on the side walls. MDF or sololit is an alternative though...

fonman 10th October 2006 02:42 PM

Do you need the frames ?

I currently have a bunch of panels made like: (1) 1" 705FSK (foil out), backed by (3) 1" 703's. All four are together making a 4" panel wrapped tightly in a homemade burlap "pillowcase".

When I put them in the corners as bass traps, I put the foil side away from the wall, and when I use them as absorbers, I put the foil side to the wall.

I just noticed a lot of people doing frames. Is there a reason other than aesthetics, and increased mounting ability ?

Have I done it wrong ?

Cojo 10th October 2006 06:54 PM

You don't need frames. I did the frames just to make them sturdy and look good.