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Best material for acoustic panels - Page 2

post #31 of 86
Quote:
Originally Posted by flyng_fool View Post

The lower the freq you're trying to tame, the thicker the panel has to be.

this comment is meaningless unless you *also* factor in density (gas flow properties) of the insulation/material

if you have the luxury to lose 12" of real estate, it's more beneficial to go with the cheap rolls of pink fluffy home insulation, and loosely fill the cavity.

the denser stuff (oc705) is good if you cant eat up much real estate, but the thicker the trap, the less dense youll need to make it.
post #32 of 86
A lot of the corner bass traps I've seen have been built out of OC703 cut at a 45 and placed into the corner. Everybody that has been discussing them has said that thin panels will not work on long wavelength low frequency sound, you need something a lot thicker to tame that.
post #33 of 86
Quote:
Originally Posted by cdy2179 View Post

If you're handy I don't see why anyone would "BUY" panels. For $18 (give or take) a panel You can DIY panels that looks just as good as what GIK sells. Buying from others is really paying them to DIY (they build it just like you can) and then sell it to you.

Of course if you just aren't the DIY type you can spend 3-4 times as much and get the same thing.

Yep GIK panels are ridiculously expensive. I could buy them if I am a ball player.

I bought the 703 panels from a local insulation dealer. It is a lot cheaper to buy the 703 from a local company than get it online. They come in a pack of 12 if I remember correctly. If you order by phone, make sure you tell them it is for HT (yes they know people use it for HT) and tell them to deliver a box with the panels in good shape. The box is basically cardboard wrapped around. First time I struggled by getting the panels in my Civic! Next time I asked them to deliver a box. They charged $20 to deliver.



You can buy the Gilford of maime cloth to cover the panels. Actually the fabric is more expensive than the 703 panels! Some say that felt cloth is also as acoustically transparent as the Gilrford of maime cloth. I didnt cover them as no one visits my house :-)
post #34 of 86
Quote:
Originally Posted by localhost127 View Post

this comment is meaningless unless you *also* factor in density (gas flow properties) of the insulation/material

if you have the luxury to lose 12" of real estate, it's more beneficial to go with the cheap rolls of pink fluffy home insulation, and loosely fill the cavity.

the denser stuff (oc705) is good if you cant eat up much real estate, but the thicker the trap, the less dense youll need to make it.

Well it is not meaningless. It was a very general statement. 703 panels come in different thicknesses. So if you want to use as bass trap you have to use a thicker 703 panel. Of course if you can find a panel of different material that is thinner and denser then it is fine too.

If you want to use a 4" panel and a build a corner triangular trap, you will have a hard time cutting them. So people use the 2" panels and stack the triangular pieces. You can buy a 2" thick 2'x4' panel and just place them in the corner but 4' height is going to be enough. Edit: I meant to say that 4" height is not going to be enough
post #35 of 86
Quote:
Originally Posted by Mupi View Post
Well it is not meaningless. It was a very general statement. 703 panels come in different thicknesses. So if you want to use as bass trap you have to use a thicker 703 panel. Of course if you can find a panel of different material that is thinner and denser then it is fine too.

If you want to use a 4" panel and a build a corner triangular trap, you will have a hard time cutting them. So people use the 2" panels and stack the triangular pieces. You can buy a 2" thick 2'x4' panel and just place them in the corner but 4' height is going to be enough.
no, you dont have to use a thicker 703 panel, you just combine panels into one thick trap.

and my comment was in regards to very thick traps (e.g. 12") ... where 703 may not be the best density fiberglass to use.
post #36 of 86
OK..I am a little unsure of what is needed in a room. I am going to be building a dedicated theater room in my basement.

The floor is going to be burbur carpet ontop of a thin pad and poured concreted.

The walls, one side is a false wall erected to divide the basement, wood and drywall. One side is an outside wall with drywall over insulation. One wall is an "outside" (I live in a townhome, it faces another home) wall, with drywall over insulation over cinder block. The final wall is drywall over insulation over poured concrete.

The roof is a hanging ceiling over insulation. The room dimensions will be approx. 14 ft long by 9 ft wide by 7.5 ft high.

My current plan is to have two rows of seating, the back raised by 6 inches (just to help out with the viewing some, but due to low ceiling not too big an increase), a projector to a screen, and an 11.2 speaker setup (height, wide, rears, and standard 5.2).

What type of acoustic alteration does this type of room need?
post #37 of 86
You should go to the portion of the forum that is the Dedicated Theater Design and Construction thread. You'll finds tons of info for what you're looking for.

http://www.avsforum.com/avs-vb/forumdisplay.php?f=19
post #38 of 86
Quote:
Originally Posted by localhost127 View Post

no, you dont have to use a thicker 703 panel, you just combine panels into one thick trap.

and my comment was in regards to very thick traps (e.g. 12") ... where 703 may not be the best density fiberglass to use.

You mean the OC703 that Dennis Erskine and Ted White recommend?
post #39 of 86
Quote:
Originally Posted by localhost127 View Post

no, you dont have to use a thicker 703 panel, you just combine panels into one thick trap.

It is the same thing. You just need more "thickness/density". You may use 4 1" panels or just use 1 4" panel of the same material. The basic idea is that you need more thickness/density to control low frequency. A lot gets lost in an email communication!

If you use 1" panels to make corner traps, you will be cutting a lot of them. If you use 4" panels you will have a hard time cutting it unless you have the tools. I could cut the 2" panels with a $20 powered kitchen knife. That is the trade off. The knife got blunt after a few panels but I managed to finish cutting all the panels.

I doubt if anyone who makes DIY bass traps uses 12" 703 panels. 2" panels are the most widely used for corner traps. Does OC even make 12" panels?
Anyway... go to that big thread for more on bass traps.
post #40 of 86
Quote:
Originally Posted by cybrsage View Post

OK..I am a little unsure of what is needed in a room. I am going to be building a dedicated theater room in my basement.

The floor is going to be burbur carpet ontop of a thin pad and poured concreted.

The walls, one side is a false wall erected to divide the basement, wood and drywall. One side is an outside wall with drywall over insulation. One wall is an "outside" (I live in a townhome, it faces another home) wall, with drywall over insulation over cinder block. The final wall is drywall over insulation over poured concrete.

The roof is a hanging ceiling over insulation. The room dimensions will be approx. 14 ft long by 9 ft wide by 7.5 ft high.

My current plan is to have two rows of seating, the back raised by 6 inches (just to help out with the viewing some, but due to low ceiling not too big an increase), a projector to a screen, and an 11.2 speaker setup (height, wide, rears, and standard 5.2).

What type of acoustic alteration does this type of room need?

It does not matter what your room size is. It all depends on how much you want to spend. If you have the budget you can get the GIK panels. But if you dont want to spend several 1000 bucks on treatment then of course you have to make your own panels.

OC703 2" panels are widely used. You can also use other materials but they are not as rigid as the 703 so it may not be easy to cut them. If you dont care about looks you dont have to cover the 703 panels. I have just placed them leaning againts the wall behind speakers and on side walls.

Go to that big thread. There is a lot of information in that thread. That is where I started.
post #41 of 86
Quote:
Originally Posted by flyng_fool View Post

You should go to the portion of the forum that is the Dedicated Theater Design and Construction thread. You'll finds tons of info for what you're looking for.

http://www.avsforum.com/avs-vb/forumdisplay.php?f=19

Did not know that sub-forum existed. Thanks!
post #42 of 86
Ethan Winer has a great site for information about this & more.
http://www.ethanwiner.com/acoustics.html
post #43 of 86
Quote:
Originally Posted by Mupi View Post

It is the same thing. You just need more "thickness/density". You may use 4 1" panels or just use 1 4" panel of the same material. The basic idea is that you need more thickness/density to control low frequency. A lot gets lost in an email communication!

if you read the original comment i was replying to, that's exactly the confusion i was trying to clean up - that you can combine multiple panels into one larger, vs the original comment "703 panels come in different thicknesses. So if you want to use as bass trap you have to use a thicker 703 panel."



Quote:
Originally Posted by Mupi View Post

I doubt if anyone who makes DIY bass traps uses 12" 703 panels. 2" panels are the most widely used for corner traps. Does OC even make 12" panels?
Anyway... go to that big thread for more on bass traps.

sorry, but 2" traps in the corners is not going to do anything for LF. if you are claiming that, please provide before and after measurements of your room. and if you're talking about 2" panels COMBINED to form thicker traps, then by all means yes, of course.

and yes, some people have the luxury of building 12" thick traps - which is by all means better, as the further from the wall you are the closer you are to LF 1/4 wavelength points (to speak generally) - which is what you want for velocity based porous absorption... the point i was raising, is that the deeper the trap you build, you need to start using less dense materials. e..g 12" of OC705 will probably reflect LF, instead of absorbing. with that thick of a trap, you'd want to use less dense material (cheap pink fluffy stuff).
post #44 of 86
Quote:
Originally Posted by flyng_fool View Post

You mean the OC703 that Dennis Erskine and Ted White recommend?

i dont understand this comment?
post #45 of 86
Quote:
Originally Posted by localhost127 View Post





sorry, but 2" traps in the corners is not going to do anything for LF. if you are claiming that, please provide before and after measurements of your room. and if you're talking about 2" panels COMBINED to form thicker traps, then by all means yes, of course.

and yes, some people have the luxury of building 12" thick traps - which is by all means better, as the further from the wall you are the closer you are to LF 1/4 wavelength points (to speak generally) - which is what you want for velocity based porous absorption... the point i was raising, is that the deeper the trap you build, you need to start using less dense materials. e..g 12" of OC705 will probably reflect LF, instead of absorbing. with that thick of a trap, you'd want to use less dense material (cheap pink fluffy stuff).

And I contend that OC 703 is fine for bass traps. Look at the thumbnails that Mupi posted and you will see how people are using OC 703 as bass traps. The front to rear depth is greater than 12" or so.

If you don't know who Dennis Erskine and Ted White are then perhaps you should do a search for them. They are the foremost authorities on room treatments and soundproofing.
post #46 of 86
Quote:
Originally Posted by flyng_fool View Post

And I contend that OC 703 is fine for bass traps. Look at the thumbnails that Mupi posted and you will see how people are using OC 703 as bass traps. The front to rear depth is greater than 12" or so.

please take a moment to read and comprehend what im saying.

also please understand the differences between broadband absorption and bass traps.

im not advocating that oc703 isnt effective. what i was trying to communicate is that the deeper the trap, the less dense material you want to use. e.g., if you have the luxury of making extremely deep traps, you'll want to use a less dense material like pink fluffy insulation. if you keep stacking those oc703 panels together, soon or later the trap is going to start reflecting instead of absorbing. that was my original comment - sorry if it wasn't clear. no one is advocating 6" of oc705 isnt highly effective in the corners.

you generally want deeper traps to get the porous insulation closer to the 1/4wavelength of the LF frequencies...which means spacing it from the wall or building very deep traps. if you're doing this, less dense material will work better.

most don't have the luxury of doing this, hence straddling oc703/705 (dense, rigid fiberglass) in the corners or building superchunks style corner traps.


Quote:
Originally Posted by flyng_fool View Post

If you don't know who Dennis Erskine and Ted White are then perhaps you should do a search for them. They are the foremost authorities on room treatments and soundproofing.

no disrespect, but their reputation surely doesnt disprove existing gas flow properties of porous material, does it?
post #47 of 86
Quote:
Originally Posted by localhost127 View Post


please take a moment to read and comprehend what im saying.

also please understand the differences between broadband absorption and bass traps.

im not advocating that oc703 isnt effective. what i was trying to communicate is that the deeper the trap, the less dense material you want to use. e.g., if you have the luxury of making extremely deep traps, you'll want to use a less dense material like pink fluffy insulation. if you keep stacking those oc703 panels together, soon or later the trap is going to start reflecting instead of absorbing. that was my original comment - sorry if it wasn't clear. no one is advocating 6" of oc705 isnt highly effective in the corners.

you generally want deeper traps to get the porous insulation closer to the 1/4wavelength of the LF frequencies...which means spacing it from the wall or building very deep traps. if you're doing this, less dense material will work better.

most don't have the luxury of doing this, hence straddling oc703/705 (dense, rigid fiberglass) in the corners or building superchunks style corner traps.

no disrespect, but their reputation surely doesnt disprove existing gas flow properties of porous material, does it?

Um so what do I use to cut into triangles to put in the corners and stack 8 feet to the ceiling?
post #48 of 86
Quote:
Originally Posted by dissonance79 View Post
Um so what do I use to cut into triangles to put in the corners and stack 8 feet to the ceiling?
there is no single answer for that question...there's plenty of variables.

and im not talking about height ... im talking about depth of the trap.
do you understand how porous/velocity-based absorption works?
post #49 of 86
Quote:
Originally Posted by localhost127

there is no single answer for that question...there's plenty of variables.

and im not talking about height ... im talking about depth of the trap.
do you understand how porous/velocity-based absorption works?
No I just want to stack triangles in my corner and have it work.
post #50 of 86
Quote:
Originally Posted by dissonance79 View Post
No I just want to stack triangles in my corner and have it work.
When you cut triangles to put in the corner, each panel yields 8 triangles so at 2" thick per panel, that's 16" height per panel. Six panels will give you 96" of coverage (8 ft.).

scroll to bottom for the pattern:

http://forum.studiotips.com/viewtopic.php?t=535

I have links at the house for you tube videos on cutting it and finishing the corners for a completed look if no one posts them first.
post #51 of 86
Quote:
Originally Posted by citizen arcane View Post

When you cut triangles to put in the corner, each panel yields 8 triangles so at 2" thick per panel, that's 16" height per panel. Six panels will give you 96" of coverage (8 ft.).

scroll to bottom for the pattern:

http://forum.studiotips.com/viewtopic.php?t=535

I have links at the house for you tube videos on cutting it and finishing the corners for a completed look if no one posts them first.

you can do larger chunks (34" face) ... by only making 4 triangles per panel.
post #52 of 86
I was at Lowes today and they had what "looked" like rigid OC703 fiberboard. They where Armstrong acoustic ceiling panels and came in a case. One size they had also looked just like the standard 2x4' size and everything. Anybody know about this stuff and how close it is to OC703 in effectiveness?

In the back of the lumber section they also had what looked like standard 4x8' plywood size fiberglass board but with a tin foil like covering. I peeled a little of the tin foil off to see how easy it would be to remove it and it peeled right off easily with no effort and without damaging the fiberglass underneath. What about this stuff? Could this be used to make acoustic panels?

People keep mentioning GIK panels but ATS is still the cheapest for finished panels that I've found... If I can't find something locally EASILY I'll probably just buy finished panels from ATS...
post #53 of 86
Quote:
Originally Posted by Emig5m View Post

I was at Lowes today and they had what "looked" like rigid OC703 fiberboard. They where Armstrong acoustic ceiling panels and came in a case. One size they had also looked just like the standard 2x4' size and everything. Anybody know about this stuff and how close it is to OC703 in effectiveness?

In the back of the lumber section they also had what looked like standard 4x8' plywood size fiberglass board but with a tin foil like covering. I peeled a little of the tin foil off to see how easy it would be to remove it and it peeled right off easily with no effort and without damaging the fiberglass underneath. What about this stuff? Could this be used to make acoustic panels?

People keep mentioning GIK panels but ATS is still the cheapest for finished panels that I've found... If I can't find something locally EASILY I'll probably just buy finished panels from ATS...

http://www.bobgolds.com/AbsorptionCoefficients.htm
post #54 of 86
Quote:
Originally Posted by localhost127 View Post

http://www.bobgolds.com/AbsorptionCoefficients.htm

There's just too much info there to sift through. Yea, I'm a lazy bastage, hehe. There should be another page that sorts and groups similar performing material together instead of sorted and grouped by brand.
post #55 of 86
Quote:
Originally Posted by localhost127 View Post

please take a moment to read and comprehend what im saying.

also please understand the differences between broadband absorption and bass traps.

im not advocating that oc703 isnt effective. what i was trying to communicate is that the deeper the trap, the less dense material you want to use. e.g., if you have the luxury of making extremely deep traps, you'll want to use a less dense material like pink fluffy insulation. if you keep stacking those oc703 panels together, soon or later the trap is going to start reflecting instead of absorbing. that was my original comment - sorry if it wasn't clear. no one is advocating 6" of oc705 isnt highly effective in the corners.

you generally want deeper traps to get the porous insulation closer to the 1/4wavelength of the LF frequencies...which means spacing it from the wall or building very deep traps. if you're doing this, less dense material will work better.

most don't have the luxury of doing this, hence straddling oc703/705 (dense, rigid fiberglass) in the corners or building superchunks style corner traps.




no disrespect, but their reputation surely doesnt disprove existing gas flow properties of porous material, does it?

What I was trying to communicate is that both of these men make a living off of dealing with soundproofing and acoustic treatments. They know more about it than just about anyone else. If they say something is effective, I believe them. You would do well to believe their advice as well. They have the experience and measurements to back up their assertions.
post #56 of 86
Quote:
Originally Posted by flyng_fool View Post

If they say something is effective, I believe them. You would do well to believe their advice as well. They have the experience and measurements to back up their assertions.

what exactly do you think im out of agreement with them on?
i fail to understand what exactly of my commentary you are debating?
post #57 of 86
Quote:
Originally Posted by localhost127 View Post

if you read the original comment i was replying to, that's exactly the confusion i was trying to clean up - that you can combine multiple panels into one larger, vs the original comment "703 panels come in different thicknesses. So if you want to use as bass trap you have to use a thicker 703 panel."





sorry, but 2" traps in the corners is not going to do anything for LF. if you are claiming that, please provide before and after measurements of your room. and if you're talking about 2" panels COMBINED to form thicker traps, then by all means yes, of course.

and yes, some people have the luxury of building 12" thick traps - which is by all means better, as the further from the wall you are the closer you are to LF 1/4 wavelength points (to speak generally) - which is what you want for velocity based porous absorption... the point i was raising, is that the deeper the trap you build, you need to start using less dense materials. e..g 12" of OC705 will probably reflect LF, instead of absorbing. with that thick of a trap, you'd want to use less dense material (cheap pink fluffy stuff).

Take a good look at the picture I posted. I am making triangles from a 2" thick 2'x4' panel. I am not just placing a 2" panel at the corner. Someone already mentioned how to make triangles out of the panels. So many people have done this corner trap. This is nothing new. The height of the triangle basically is the depth of the corner trap. If you make bigger triangles you get a deeper/thicker trap. I made 8 triangles from each 2'x4' panel and stacked them up. This is also the number most people used in that thread.

Not every room needs this kind of passive control. Room correction using Anti-Mode or Audyssey etc. is good enough in most cases. The improvement from passive control is not going to be significant depending on how much material is used. It may be more effective and economical to get an AVR that has Audyssey or just get the Anti-Mode 8033 for $350.

I did this before I had Anti-Mode or Audyssey or Behringer parametric EQ devices. If I had them first I would not have done the passive control, especially DIY. If I had the budget I would have just bought the GIK panels and hung them on the wall. Now that I have done it I am not ripping them unless I am moving out of the house.


Anyway...Just go to that dedicated thread and read up. Otherwise you are just wasting your time here making arguments about things that is so well known and documented.

For others who are planning on doing this I suggest that you first try Audyssey MultEQ or Anti-Mode 8033. That would give you most of the improvement you are looking for. Then you could spend on putting the panels mainly to absorb mid/high frequency reflections to improve the sound stage. If your room is big and if you and the speakers are far from the walls, you may not be bothered as much by reflected sound as in a smaller room. IMO reflected sound is more detrimental to the sound stage in the case of bipolar speakers like the Magnepans (I have the MG12's), when used for 2ch music. You have to control the sound from the back of the speakers that get reflected back to you from the back wall, in addition to the reflections from the side wall.

Anyway... go to that thread and read up. You may need several days to read/search through all those pages there :-)
post #58 of 86
Quote:
Originally Posted by Emig5m View Post

There's just too much info there to sift through. Yea, I'm a lazy bastage, hehe. There should be another page that sorts and groups similar performing material together instead of sorted and grouped by brand.

There are cheaper materials if you want to deal with all the dust :-)

Like I said OC703 is not expensive at all if you buy from a local company that deals with insulation. You can get some names if you go to OC web site and look for dealers. It is not fluffy. It can stand on its own as in my picture. It is easy to cut. See how sharp the corners are in my picture. My knife wasnt that sharp. 703 is probably the unanimous choice in that dedicated thread.

Like I said the Gilfor of Maime acoustically transparent fabric is more expensive than the 703 panels. I have I have given some useful information here to start.

Like I also said, dont expect miracles from passive bass control. Try room correction first. Anti-Mode 8033 is the cheapest device you can get and it performs just as good as Audyssey. I use Audyssey on top of antimode like many people. You may not need audyssey at all unless you want dynamic volume/dynamic eq. I dont care much to EQ the full range using Audyssey as I use the Behringer DEQ2496 with a 31 band GEQ per channel to tame down the mids. So I dont rely on Audyssey to control other channels.
post #59 of 86
Quote:
Originally Posted by Mupi View Post

Take a good look at the picture I posted. I am making triangles from a 2" thick 2'x4' panel. I am not just placing a 2" panel at the corner.

i stated it both ways - as you weren't perfectly clear in your original post whether you were using 2" thick panels in the corners, or stacking multiple 2" panels together to form a larger trap. re-read your original post i quoted...it's your own words and it wasn't clear. hence why i stated it both ways.

Quote:
Originally Posted by Mupi View Post

Someone already mentioned how to make triangles out of the panels. So many people have done this corner trap. This is nothing new.

that is not the point of my commentary in this thread. can you please take a moment to read and understand what i wrote instead of presenting ridiculous commentary which is meant to distract others from the fact that you're arguing a point in which i never stated??? it was merely to note that the deeper/thicker trap you go (e.g. 12"), you want to use less dense material. that was all.

Quote:
Originally Posted by Mupi View Post

The height of the triangle basically is the depth of the corner trap. If you make bigger triangles you get a deeper/thicker trap. I made 8 triangles from each 2'x4' panel and stacked them up. This is also the number most people used in that thread.

why didnt you go with a deeper trap? (34" face - 4 triangles per oc703 panel). the point of the deeper trap with porous absorption is you have more absorption away from the wall, closer to 1/4wavelengths of lower freqs. not that it doesn't help (especially with decay), but you're not providing any reasoning as to why you did such -- for other passive readers interested in the subject in this thread. and just doing it because it's "what the other people in the thread did most" just means your blindly following without understanding how the porous absorption is working. not that you need to understand 100% (as i dont),, but if you're going to argue against my commentary that you should begin using less dense material once you start making your traps so thick, then by all means provide some opposing insight.

Quote:
Originally Posted by Mupi View Post

Not every room needs this kind of passive control. Room correction using Anti-Mode or Audyssey etc. is good enough in most cases. The improvement from passive control is not going to be significant depending on how much material is used. It may be more effective and economical to get an AVR that has Audyssey or just get the Anti-Mode 8033 for $350.

completely wrong. room correction/eq is only good for a particular sweet spot; freq response changes as you move your head around. also, could you please detail for me how room correction and/or eq is lowering decay times in the room? or how room correction deals with early reflections once the signal has left the speaker?

Quote:
Originally Posted by Mupi View Post

I did this before I had Anti-Mode or Audyssey or Behringer parametric EQ devices. If I had them first I would not have done the passive control, especially DIY. If I had the budget I would have just bought the GIK panels and hung them on the wall. Now that I have done it I am not ripping them unless I am moving out of the house.

see above. eq or room correction is good icing on the cake, but it's not the first step in treatment by any means.


Quote:
Originally Posted by Mupi View Post

Anyway...Just go to that dedicated thread and read up. Otherwise you are just wasting your time here making arguments about things that is so well known and documented.

one last time - can you please provide or state my arguments (quote me) on which i said anything that is not in agreeance with everyone else?

you keep saying im arguing against people --- i wasn't aware i was making any arguments besides noting that if you're making very deep traps, you want to use less dense material. im not going back and forth with you on this - please quote me what i have said that you feel is incorrect.
post #60 of 86
Quote:
Originally Posted by Mupi View Post

Like I also said, dont expect miracles from passive bass control. Try room correction first. Anti-Mode 8033 is the cheapest device you can get and it performs just as good as Audyssey. I use Audyssey on top of antimode like many people. You may not need audyssey at all unless you want dynamic volume/dynamic eq. I dont care much to EQ the full range using Audyssey as I use the Behringer DEQ2496 with a 31 band GEQ per channel to tame down the mids. So I dont rely on Audyssey to control other channels.

what is audyssey or eq going to do if you're sitting in a -30dB null? or have 500ms modal ringing at 80hz??
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