How I built my bass traps...

[6pod9]

You are my savior mate. Very thanks for the advises.

I just need to get paid or this dream will not come true...

69

[jaykay]

Ok, so I've been really lazy in doing my show and tell side of things but here you go. Thanks to this thread I had a good idea of which materials to use and how to go about building my traps.

A friend and I bought a pallet of insulation material (Gutex Thermoflex) along with a whole bunch of wood pre cut to the lengths we required as we were going to be building the bass traps together. In total we were building 42, 22 for me and 20 for him. During this time my house was somewhat chaotic with stuff everywhere, it's times like that that I really miss having a garage or the likes.





I then set about calculating and drawing out the holes on a template that I planned to drill through the wood. This was a little more difficult than it sounds because I wanted the holes perfectly spaced, even at the joins. In total there are 19 holes on the long piece and 9 on the short piece. I first built a prototype to make sure everything would work out.



I decided I was going to stain the frames black and white as my whole room is black and white as is the material I chose to cover them in.



Keep in mind, to get to the stained stage there was a hell of a lot of drilling and sanding which almost drove me insane!! After the staining I then countersunk holes on the lengths of wood where the screws would go through to keep the frames together. Unfortunately at that time of year in Berlin (summer) it was either very hot or raining which meant some of my wood warped slightly. Kind of pissed me off but what can you do?



Once the frames were assembled it was a simple matter of getting the material in and stapled tight to the frames.

[jaykay]

I wanted the material flush with the front panel so I bought some long thin strips of wood and staple gunned through it into the frame to give a nice edge that is invisible from the outside.



As you can see, nice and flush with the front...



After that part it was a downhill run, I just had to fit the insulation into the frames which was a snug fit as I'd deliberately undersized the frames by 5mm.



After stapling the fabric into the top sides I then decided to just sew the back up, it seemed like the easiest solution at the time and worked out really well.



And that's it. A finished product. I had a real deadline as my wife's 30th was coming up and I'd promised the apartment would be in order by the time that came around. So all in all it probably took me about a month and a half to get them all done, it was really a lot more work than I'd bargained on but definitely worth it in the end.

[pan60]

nice!!!!

[Weasel9992]

Those look killer! **Love** the frames.

Frank

[jaykay]

Thanks

[vespiz]

From experience, I can tell that drilling those holes into the frame is a heck of a job.
And you did more than me!

[finlove]

Just wondering I took photo from this room calibrating software and this is the pic that came out http://s361.photobucket.com/albums/oo54/finlove/?action=view&current=P IC_1021.jpg

Is my room in bad shape?is it bad reflextions?
Do I need bass trap or what?
Thanks

[Weasel9992]

Originally Posted by finlove

Just wondering I took photo from this room calibrating software and this is the pic that came out http://s361.photobucket.com/albums/oo54/finlove/?action=view&current=P IC_1021.jpg

Is my room in bad shape?is it bad reflextions?
Do I need bass trap or what?
Thanks

I think I answered you somewhere in some other internet forum. As I said there, this is only an impulse response graphic. It has only to do with the decay time in the room at a particular frequency...it has NOTHING at all to say about the low end response in the room. You need to use room EQ wizard or fuzzmeasure to find that out. What you have right now will be totally unhelpful in determining how many of what type bass trap you'll need.

Frank

[finlove]

Ah ok

Im using room eq now but I keep getting leve is too low when I run measurement test?

[Weasel9992]

Originally Posted by finlove

Ah ok

Im using room eq now but I keep getting leve is too low when I run measurement test?

I'm talking about using a specific measuring software...Room EQ Wizard. It's a free download that you can get here. You'll need a PC and an omni-directional mic to use it. What you are using is an impulse measurement software, only useful for determining the decay time at a particular frequency.

Frank

[F5D]

I just picked up rockwool and some wood for building big 124cm x 124cm x 14.5cm broadband absorbers for my early reflection points. I will use the same Paroc FPS14 wool (66 kg/m^3) that I used earlier for my other absorbers (4x 120cm high corner traps + 3x 124x64x15 flat ones). I will put 2x 5cm layers of the wool in the frame and leave 4.5cm free space behind the wool. I will use felt in front and behind of the frame in addition to a white finishing fabric to avoid the dust. These will definitely suck some bass too. I will post some pics when I get them ready. I will probably start building them tomorrow.

[BF_]

Great thread! My trapping was built on to the outside edge of inside out walls so the implementation is a little different, but they do share many of the concepts.

The popular frame with holes, made from 1x6 in this case.


The fabric covering will be stretched across the face between a pair of 1x2s. The small posts along the sides of the frame are to secure the 1x2s.


The frame fits floor to ceiling, and edge to edge on the front splay walls. It was tapped into place, then screwed into the frame of the walls and the rafters in the ceiling above.


The holes covered with bits of scrap.


Screws were placed inside the cavity to maintain the airspace behind the trap, the two layers of oc703 placed within.


Insulation filling the frame.

[BF_]

continued due to limit on photos per reply.

Sizing the covering before cutting.


Tuck the excess fabric between the wood and insulation at the top and bottom.


and fin.


Rear wall done the same way.

[Weasel9992]

Wow...those look great! Nice neat job. how does the room sound? How tough were the soffit mounts?

Frank

[BF_]

Thanks Weas. I'm happy with the results, although I still have a bit of wall/ceiling corner trapping to finish. The soffits, believe it or not, were much easier to build than design. Do your homework thoroughly before jumping into soffits, and remember it has the chance of being a crap shoot. Understand the function of the elements involved as many of the pictoral resources avaliable are not the most intuitive.

[F5D]

Ok, I promised some pics of my new traps, so here goes:

Paroc FPS14 rockwool:


Two frames 1240 x 1240 x 145 (mm)


Two layers of rockwool installed, leaving a 45mm air gap behind:


Wool sealed by very thick felt, ready for finishing fabric:


One of the traps in use at the first reflection point:

[Weasel9992]

Those look very much like a couple I made a few years ago.

Frank

[nicolasmasset]

Nice traps, F5D. Can you hear the difference?

[F5D]

Originally Posted by nicolasmasset

Nice traps, F5D. Can you hear the difference?

Thanks. Well, earlier I had smaller traps (shown slightly under the new bigger trap) and pyramid shaped basotect foam at the early reflection points, so I basically had those points covered but of course the stereo image is now more stable due to bigger, heavier and more uniform traps. It also seems that the bass is hitting tighter.

I will measure the frequency response today and set the master eq again. I use 828 mk3 dsp eq for attenuating (not boosting) a couple of room modes in addition to acoustic treatment and it has been working well. Without the eq, frequencies like 130hz are peaking so much that it is impossible to listen to anything without paying attention to those frequencies at all times. Some others might go and try switching the monitors but that is not the problem, it is the room and my big desk although I use separate monitor stands behind it. If I put the monitors on the desk, the sound is nothing but huge resonances.

[Matti]

I use similiar approach with an extra soundcards eq, like a manual version of
Jbl or Genelec correction systems -sparingly, just to help problem areas.

Matti

[nicolasmasset]

My room has a lot of slanted ceilings that would need treatment, but I don't think the slanted walls would hold the weight of the basstraps.

Do you guys think it's a viable option to just build man-high bass traps on stands and position them around the mixing position for when I need them. This would be real practical and leave the walls alone. Then I could also position them around the mic for when I need a vocal booth etc.

My logic says this would be a good method, as you can really create a solid wall/circle behind you with still a have room of air behind it.

[MichaelMackie]

Looks great. I'm definitely going to try to make one.

[Lemonsqueezer]

Originally Posted by Glenn Kuras

Well on a 4x2 4" panel it would give you 50% more exposed area if the sides are open.. 6"? well, check my numbers but that would be 75% more exposed would it not?

How does the extra exposure effect absorption over the the frequency range? and would this benefit for placement behind the monitors?

[Lemonsqueezer]

Originally Posted by SkiBum

I'm not a professional acoustician, but I have studied the subject enough to know there is some missing data in this long thread. I have a couple comments:

First, about the traps mentioned in the original thread, these are not bass traps. They are full range absorbers. If you use 6" of 703 you have a full range absorber, like an open window - all sound goes in and does not come out. To absorb bass only, you have to either use a membrane design or a Helmholz resonator.

You should be able to get bass absorbtion by putting them in your corners at 45degrees to the walls, where the bass builds up.

Another post said that you can leave plastic wrapped around the 703 and they work almost as well. Sorry, but that's illogical if you know how they work. The air pressure waves go into the material and are absorbed. If the waves can't get into the inside of the material they are not going to have any significant effect at all.

I would recommend studying more about the subject before building traps or you won't get the great results you are after for your hard work and money. Dalton Everest's books are excellent.

I made traps - 3 kinds: low mid and full range - based on his designs and with his calculations, and they worked beautifully in my old studio.

Also, hemp may have a sound absorbtion rating that is decent (although I doubt it), but I would want to actually know before I used it in my studio, although I applaud you for finding a healthier material than fiberglass (cotton batting works pretty well). I just hope it is really working for you. Considering how much you put up it might do OK on some frequencies. You can probably find an acoustic rating for it somewhere. Maybe the manufacturer can help with that.

I'm not trying to be a know it all or rain on anybody's parade. Acoustics is a fun subject. Understanding the science, it can be even more useful.

Would love some more info on your traps. Sounds interesting. Some pics would be cool as well.

[Lemonsqueezer]

Originally Posted by Sandersonic

Hi All,
Here are some panels I built for my control room. They are all 120cm x 180cm (measured inside the frame) to accommodate standard panel sizes of Rockwool and 2" Auralex Studiofoam. Each unit has 3 rockwool 5cm slabs and 3 2" Studiofoam panels placed edge to edge. The Rockwool is behind the Auralex foam and is held in place by a small lip made of 2cm x 2cm trim. I then fastned the Studiofoam to the rockwool and hung each unit on chains. The panels on the right side and in the rear of the control room are hung within the window recesses so as not to protrude out into the room yet still hang free from the walls. Also, beneath the rear panel it a futon spaced a bit off the wall. There's a small hammock-like storage space underneath it that I filled with pillows & blankets to help with absorption. Makes a fine sofa too!

I'm following this post with another to detail the overhead panels....

They look really good.

I have some of the same Auralex foam as yourself. I also have been thinking of using them as a front to some traps for the early reflections.

What confuses me is the being able to breath through the covering material thing!!! I am guessing that the Auralex foam will absorb the mid and highs (as well as maybe some dissipation because of the design) and then the rockwool will deal with the bass. The more rockwool, the lower the bass absorption.

Have I got this right or am I talking bol@@*s?

Would love to here from the experts on this.

[JimmySX]

This is a really helpfulol thread for me right now! I'm in the middle of building some DIY acoustic panels and basstraps. I will make some pics and post them here to share with you guys and to hear your opinions! thumbsupthumbsupthumbsup

[Lemonsqueezer]

Originally Posted by F5D

Wool sealed by very thick felt, ready for finishing fabric:

Is felt OK to use for a trap that will be used for a first reflection point?

[kraskland]

Originally Posted by F5D

Ok, I promised some pics of my new traps, so here goes:

Wool sealed by very thick felt, ready for finishing fabric:

Did you use any batting before adding the final white fabric? I'm looking at doing something similar but am a bit concerned about the wood edge damaging the fabric.

[F5D]

To answer the two questions, I did not use anything between the felt and finishing fabric. The felt softens the edges enough so that there is no risk of breaking the finishing fabric, at least in this case. The felt that I used is very soft but also very dense that it works as a filter. It does not reflect high frequencies easily. It absorbs the sound and also let's it thru to the wool layers. If you play music in the room and put one of your ears close to the trap, you can easily hear that "nothing" is reflecting back from the traps. Of course it depends on the felt type you use.