The No.1 Website for Pro Audio
 All  This Thread  Reviews  Gear Database  Gear for sale     Latest  Trending
Fabric for bass traps and ...
Old 24th April 2006
  #1
Lives for gear
 
SK1's Avatar
 

Fabric for bass traps and ...

Ok .....

Thanks to you guys I found the 705 owens corning fiberglass for $2.57 a sq ft to build broad band absorbers for my room

(CWCI , CITY OF INDUSTRY 626-369-4424 los angeles)

My question is what are the specs on the fabric I should use to cover the traps ??
My wife wants to do somthing away from the norm .... maybe a patterned fabric or somthing. Should it be linen ??? I've heard you should be able to "blow through the fabric" Is that true ???
I've got some micro-suede .... would that work ???

Also, I noticed on the ready traps site it says you can strengthen the edges of the fiberglass with clear packing tape. Would the packing tape affect the effectivness of the traps ?? If so ..... how much of a difference would it make ??

I'll be building these 4" to 6" deep.

Any help would be GREATLY appreciated
Old 24th April 2006
  #2
Lives for gear
 

EDIT - you said broadband, not bass trap.

The fabric will make a very small difference, but it's still basically cosmetic. Just don't go too thick or too airtight.
Old 24th April 2006
  #3
Gear Maniac
 

Agreed, how ever, the membrane should need to "move" to some degree to ad low frequency absorption. If it does not, it will not. Painting an "open" cell foam, effectively "closes" the cell and helps to almost no extent.

If I were you, I would consider a more broad band approach (as suggested above) as there will really be more bang for your buck. Even a somewhat "breathable" fabric will allow a number of frequencies to be affected, and in the end, what you want is "flatter" response curve, not just a dip at say, 100hz-60hz.

Discount fabric stores are great places to look around in and offer the best prices. Man, I go nuts in those places though!

Good luck to you,
Old 24th April 2006
  #4
Gear Maniac
 

Hey SK1, I missed the part about the packing tape. Doh!

Using such will reflect some high frequencies (not a band thing in most cases), but use it sparingly, and only to "form" the corner. If you can find any kind of thin corner moulding from a hardware or home store, and cut it to length, you can get a really nice, square corner.

Good luck again!
Old 24th April 2006
  #5
Lives for gear
 
SK1's Avatar
 

Pardon my ignorance on this ........

If I build 4" thick fabric covered 705 gizmos for the corners of my room are they broad band absorbers or bass traps ??

I'm trying to get a handle on this stuff.




broad band right ???
Old 24th April 2006
  #6
Lives for gear
 

I would call that broad band.

It's really easy to kill hi frequencies - any old absorbant will do that.

The absorants get less effective on the mids, and almost ineffective on the lows.

If the absorbant is thick enough (in feet!), it can handle the whole range. Large air gaps are almost as good as total thickness, so foam with an airgap is basically a broadband absorber.

Think about wavelength. Picture a bass sinewave. Where is the air at minimum velocity (zero crossing)? At the wall. Where is it at maxium velocity? At 1/4 wavelength. (Half wavelength would be another zero crossing). Absorbants work by turning air molecules velocity into heat. Put it where the air is moving fastest.

Bass trapping is the hardest. One way to trap just the bass is to hide your absorbant behind a reflective surface. The hi's and mid's bounce off, and the low's get in and are absorbed. You can perforate this surface to make it more of a broadband absorber.
Old 24th April 2006
  #7
Gear Maniac
 
Phunkeman's Avatar
I used speaker grill material. From a Jo ann's or Hancock or any material store. I believe if you can blow air through the material it will be ok on the high freqencies.
Old 24th April 2006
  #8
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by SK1
Pardon my ignorance on this ........

If I build 4" thick fabric covered 705 gizmos for the corners of my room are they broad band absorbers or bass traps ??

I'm trying to get a handle on this stuff.




broad band right ???
Broad band is just a term for a bass trap that also picks up HF. As pointed out above picking up HF is pretty easy. It is the low end that is tough to absorb. I would recommend facing the 705 with FRK. It is going to act as a membrane which will pick up more of the low end. Make sure you straddle all corners of the room with the panel. After that you would want to build (or buy) 2 inch panels for the first reflections in the room. Those are the ones you do not want to use the FRK on.




Glenn
Old 24th April 2006
  #9
Lives for gear
 
SK1's Avatar
 

Quote:
Originally Posted by myfipie
I would recommend facing the 705 with FRK. It is going to act as a membrane which will pick up more of the low end. Make sure you straddle all corners of the room with the panel. After that you would want to build (or buy) 2 inch panels for the first reflections in the room. Those are the ones you do not want to use the FRK on.




Glenn

Ok .... so do the corners with 4" thick absorbers with FRK .......

What is FRK ?????????? heh heh

Also the 1st reflections are the ones that I find by using the old mirror trick RIGHT?

Thanks for all the help so far !!!
Old 24th April 2006
  #10
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by SK1
Ok .... so do the corners with 4" thick absorbers with FRK .......

What is FRK ?????????? heh heh

Also the 1st reflections are the ones that I find by using the old mirror trick RIGHT?

Thanks for all the help so far !!!
When you buy oc705 you can get it with FRK on it. It is scim that is glued to the front. I believe you can buy it sepertly and glue it on yourself.
Glenn
Old 24th April 2006
  #11
Gear Maniac
 
Stormkloud's Avatar
 

When I made mine, I used felt to cover them. It is very " breathable" and comes in a ton of different colors. Its also very easly found in any fabric store.
Old 24th April 2006
  #12
SRS
Lives for gear
 
SRS's Avatar
 

I got my 703 at CWCI as well in Industry. Kind of a rough area, but had the stuff. I covered mine with tan colored burlap. It is quite open and you can breathe easily through it, so sound goes through very well. It looks really nice too. I used 3M spray adhesive to attach it to the 703. Did not use any corner support. the pannels are pretty rigid on their own and unless you will be moving them around a lot, they will be fine with no corner support. The cormers on mine are pretty clean 90 degree corners. It's all in the construction... I got several bundles of 2 inch 703, and doubled up for 4 inches in thickness for the corner traps, then placed R30 insulation in behind the corner traps for added benefit. Made a world of difference in 2 different studios I have made. Good luck!
Old 24th April 2006
  #13
Gear Guru
 
Ethan Winer's Avatar
 

Glenn,

> Broad band is just a term for a bass trap that also picks up HF. <

Yes, that's the right answer. Though broadband can also mean a bass trap that's not tuned, the way wood panel traps and Helmholtz absorbers are tuned. As for the original poster's question, I'd avoid taping over the edges or hardening them with epoxy as is sometimes done. As Joel pointed out, once you block the porous openings the panels absorb less.

--Ethan
Old 25th April 2006
  #14
Lives for gear
 
sardi's Avatar
 

OK, so now Im a tad confused.

If your not building frames for the 703 or Rockwool to go in, how exactly are you hangin these things from the walls/corners?

From the majority of the pics of seen, most people are using some kind of Pine like wood, constructing a frame, then inserting the Rockwool panels and stretching the material over the top and staple gunning the fabric to the back of the wood frame.

This is what I was looking at doing, then little spacers in the corner of the frames and then screwing in 2 picture hooks (one on each top 2 spacers) then hanging it on the wall. Thsu having an inch or 2 air space, then the absorber panels.

Is this not right? How else would I hang these things? And if I was not to use wooden frames, then how would I attach the material to the rockwool panels? Glue? Wouldnt that block the breathability of the Rockwool?

Any help would be much appreciated. And if anyone has pics explaining the above, that would be a most valuable resource.

Cheers.
Old 25th April 2006
  #15
Lives for gear
 
djui5's Avatar
 

You should wrap them with Guilford Of Maine fabric...it's acoustically transparent.


I get mine from this guy, he's killer.

http://www.silentsource.com/index.html
Old 25th April 2006
  #16
Lives for gear
 
SK1's Avatar
 

Quote:
Originally Posted by sardi
OK, so now Im a tad confused.

If your not building frames for the 703 or Rockwool to go in, how exactly are you hangin these things from the walls/corners?

From the majority of the pics of seen, most people are using some kind of Pine like wood, constructing a frame, then inserting the Rockwool panels and stretching the material over the top and staple gunning the fabric to the back of the wood frame.



Cheers.

From what I understand wood frames will affect the absortion on the sides of the traps ...... no wood frame = more absorbtion. ( the frame would reflect sound )
I intend to glue the fabric on the 705 after using just a little bit of packing tape for the corners ..... nobody will see the back anyway.

The ready traps site has some pretty cool brackets to hang em up ( clear plastic )
That will space them away from the wall.
http://www.readyacoustics.com/products.php?cat=11

For my f'd up room I should be able to just stuff them in the corners since I have
8 foot ceilings
They should fit snug there
Old 25th April 2006
  #17
Lives for gear
 
SK1's Avatar
 

[QUOTE=djui5]You should wrap them with Guilford Of Maine fabric...it's acoustically transparent.


Well ...... we have the downtown fabric district here in Los Angeles, so I'm hoping to get a killer deal on fabric. They're mostly Persian and my best friend speaks farsi so we'll do well

My understanding is that the more transparent the fabric the more the traps will act like broad band absorbers.

If the fabric is more reflective they'll reflect more highs but still trap the bass.

Since I'm keeping a little foam , I'm thinking I can get away without using completley transparent fabric.

Please let me know if I'm off base here. heh heh
Old 25th April 2006
  #18
Lives for gear
 
djui5's Avatar
 

The reflections from fabric is worse than absorbing the high end....it would be like using foam.

If you want to reflect highs, best bet is to cover the face of your bass traps with diffusers. I'm building some right now...pictures will be up in a couple days..probably tomorrow.
Old 25th April 2006
  #19
Lives for gear
 
SK1's Avatar
 

I would love to know the thread count and EXACT MATERIAL being used in the commercial traps that we're seeing around.

microsuede ?? burlap ??

what is speaker fabric made from ???


Thanks very much for the replies people !!!
Old 25th April 2006
  #20
Lives for gear
 
sardi's Avatar
 

Quote:
Originally Posted by SK1
From what I understand wood frames will affect the absortion on the sides of the traps ...... no wood frame = more absorbtion. ( the frame would reflect sound )
I intend to glue the fabric on the 705 after using just a little bit of packing tape for the corners ..... nobody will see the back anyway.

The ready traps site has some pretty cool brackets to hang em up ( clear plastic )
That will space them away from the wall.
http://www.readyacoustics.com/products.php?cat=11

For my f'd up room I should be able to just stuff them in the corners since I have
8 foot ceilings
They should fit snug there
Yeah Im hearing you in terms of the wood affecting the abosrption, but I need some way of hangin these babies.

Thos stands are really out of the question for me. a. Cos I dont have the space and b. cos I live in Australia (shipping would murder me)

There needs to be some sort of way for me to attach hooks to the panels in order to hang them (with spacing) like a picture frame. Now I havent handled a Rockwool batt before, but Im assuming I cant just go screwing in hooks into it. It would have to break or crumble, hence the wodden frame idea.

Its very difficult to find the best solution. There is so much info out there, and Ive seen so many wood base panel desgins, and so many without that I dont know which to do. Worst thing is, most dot really have pictures of how they are being mounted. :(

Not to mention the material to cover the things in. Ethan mentioned Burlap in another thread and I was scratching my head silly til he pointed out its also referred to as Hessian in the UK. HAHAHAHA!! Now I know wtf Burlap is!! LOL!!

Also, this 703 stuff is near on impossible to find here in my City. Rockwool yes, but then I have the problem that the only stuff I seem to be able to find is 80kg - 100kg density, and I have read MANY times that it should be around the 40-50 mark and that any more could have an adverse effect.

Tis soooo hard. But Im tryin to soak in as much as possible, and try to make the BEST decision/choice.

So yeah, all info has been greatly appreciated. The more the better.

Oh yeah, and pics would be FAB!!

Cheers.
Old 25th April 2006
  #21
Gear Maniac
 

Quote:
Originally Posted by Ethan Winer
Glenn,

> Broad band is just a term for a bass trap that also picks up HF. <

Yes, that's the right answer. Though broadband can also mean a bass trap that's not tuned, the way wood panel traps and Helmholtz absorbers are tuned. As for the original poster's question, I'd avoid taping over the edges or hardening them with epoxy as is sometimes done. As Joel pointed out, once you block the porous openings the panels absorb less.

--Ethan


So what? You are here to tell Glenn Kuras that he is right with his definition? And you jumped on this thread to state that you agree with me?

What's the point?


sheesh...


Joel DuBay
Old 25th April 2006
  #22
Lives for gear
 

The point is, Ethan is a recognised expert in the field of acoustics. He also makes some of the best commercially available bass traps.
Old 25th April 2006
  #23
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Originally Posted by sardi
Yeah Im hearing you in terms of the wood affecting the abosrption, but I need some way of hangin these babies.

Thos stands are really out of the question for me. a. Cos I dont have the space and b. cos I live in Australia (shipping would murder me)

There needs to be some sort of way for me to attach hooks to the panels in order to hang them (with spacing) like a picture frame. Now I havent handled a Rockwool batt before, but Im assuming I cant just go screwing in hooks into it. It would have to break or crumble, hence the wodden frame idea.

Its very difficult to find the best solution. There is so much info out there, and Ive seen so many wood base panel desgins, and so many without that I dont know which to do. Worst thing is, most dot really have pictures of how they are being mounted. :(

Not to mention the material to cover the things in. Ethan mentioned Burlap in another thread and I was scratching my head silly til he pointed out its also referred to as Hessian in the UK. HAHAHAHA!! Now I know wtf Burlap is!! LOL!!

Also, this 703 stuff is near on impossible to find here in my City. Rockwool yes, but then I have the problem that the only stuff I seem to be able to find is 80kg - 100kg density, and I have read MANY times that it should be around the 40-50 mark and that any more could have an adverse effect.

Tis soooo hard. But Im tryin to soak in as much as possible, and try to make the BEST decision/choice.

So yeah, all info has been greatly appreciated. The more the better.

Oh yeah, and pics would be FAB!!

Cheers.
It is not that wood sides are wrong, but you have to understand that it is covering up the sides. With the sides open it is going to absorb more sound.. If all you can do is wood sides then I would go for it. One thing you can do is cut holes in the wood to let sound in.

Glenn
Old 25th April 2006
  #24
Gear Maniac
 

No offense Kiwiburger, but I was not addressing you. My question concerned the reason for and the validity of Ethan Winer's piggy back post. I am certain that you have your opinion, and I recognize it and respect it, but this is not a question that was asked of you, and that you can answer.

Thank you,

Joel DuBay
Old 25th April 2006
  #25
T9c
Gear Maniac
 
T9c's Avatar
 

Quote:
Originally Posted by Joel DuBay
No offense Kiwiburger, but I was not addressing you. My question concerned the reason for and the validity of Ethan Winer's piggy back post. I am certain that you have your opinion, and I recognize it and respect it, but this is not a question that was asked of you, and that you can answer.

Thank you,

Joel DuBay
Then maybe you shouldn't make such posts in a PUBLIC FORUM!

Can a moderator help here? This guy has a personal ax to grind in the middle of Town Square.

Thanks.
Old 25th April 2006
  #26
Gear Maniac
 

Quote:
Originally Posted by T9c
Then maybe you shouldn't make such posts in a PUBLIC FORUM!

Can a moderator help here? This guy has a personal ax to grind in the middle of Town Square.

Thanks.


Alright, I'll take your point. But I disagree with the temper of our statement. However, I respect your right to to just "say" it.

However, I believe you may be purposely overlooking my point, and I cannot make you see it otherwise if you do not want to. I don't know how or if you are affiliated, but there must be some impetus for your reaction. If I look at your point and take it at face value, what I see is that it does not bother you when a seller of a product jockey's for position in a thread without submitting that which is important to the discussion. Otherwise, your "reaction" could not make perfect sense.

But, I would ask you to also concede that this is the type of piggy-back-posting that makes anyone in my industry or any other look bad. The repeated attempts to simply "sign off" on another's opinion when a "poll" is not underway, only bolsters the point I am trying to make and that you seem to not want to accept.

This is not the time and is hardly the place (as I will concede respectfully) to discuss this topic, but I will say that this brand of drive-by advertising, and piggy back posting is a growing trend on GS and other forums and that veiled advertising does nothing for readers. It is a way to say "yeah, you're right, here's my URL or my web page where you can buy stuff" and jockey for position. If there is something in the post that adds something to the discussion, then it holds it's own water. Discussing Hemoltz resonators and their effect on single bands is one thing, but also adding that you simply agree with me, and agree with your other competitor does not make the thread "better". And as merchants and notables in our respective businesses, I think we should do what we can to make "posting" better and more pointed.

I hope some of this makes sense to you. I respect your opinion, but you made a "dig" at me that you simply cannot justify in my opinion without some affinity for my counterpart or some sympathy for this growing trend in free advertising.

I think it is time we (merchants) "try" to "begin" to offer our help in a way that does not not neccessarily showcase our repsective businesses or companies or perhaps in a way that is simply more "humble".

If you disagree, I can respect that too.

Respectfully,

Joel DuBay
Old 25th April 2006
  #27
SRS
Lives for gear
 
SRS's Avatar
 

OK. Getting back to the topic... I hung my 703 panels with large 3 inch long finishing nails. I covered the 703 with burlap, then simply naled them into place where they were needed. The ceiling may be a bit more tricky (that whole gravity thing...) I used simple oak trim piece over the ceiling pieces to add the extra support. The wall and corner pieces are mounted either directly onto the walls or spaced out with air gaps with "furring strips" generally 2 inch by 2 inch pine wood. This has worked well for me, and once I got the room tuned right, the panels never need to be moved.
Old 25th April 2006
  #28
Gear Maniac
 

Excellent!


Success is the goal, and you are there. Good luck to you~





~ Joel
Old 25th April 2006
  #29
Lives for gear
 
DeeDrive's Avatar
 

Quote:
Originally Posted by Kiwiburger
Think about wavelength. Picture a bass sinewave. Where is the air at minimum velocity (zero crossing)? At the wall. Where is it at maxium velocity? At 1/4 wavelength. (Half wavelength would be another zero crossing). Absorbants work by turning air molecules velocity into heat. Put it where the air is moving fastest.
Not to get too technical, but to clarify, a sine wave is at maximum velocity and it's 0 crossing, and minimum velocity at 1/4 wavelength, not the other way around.
Old 25th April 2006
  #30
Gear Guru
 
Ethan Winer's Avatar
 

Dee,

> a sine wave is at maximum velocity [at] it's 0 crossing, and minimum velocity at 1/4 wavelength <

Yes, but what Kiwi said is also correct. What our ears respond to is wave pressure, not velocity.

To use your electrical analogy, a device draws the most current - and thus power - at the input voltage peaks. So where the voltage is highest, the most work is being done. Even though the velocity happens to be lowest at that peak.

--Ethan
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump