Hi all,
After reviewing Johns plans for side wall and rear wall absorbers, I am wondering what is the best way to attach them to the wall? It seems like they would be heavy with all the MDF so you need to mount to a stud somehow. What has worked for any of you?
Also, once you have a peice of 703 or 705 covered in fabric, what is the best way to mount it by itself on the wall without making a frame for it? I'm using a couple of these (1") just for specific reflection treatment.
Last question (for now), when you use contact cement to glue fabric to the 703, do you pin the material until the glue sets? How do you get the fabric to fit snuggly while waiting for the glue to dry? It doesn't seem as though the glue would hold it tight enough on its own.
Thanks in advance for your assistance and experience. Some of these might seem like simple questions, but I am still new to building stuff like this.
Thanks,
S3
Hanging panel absorbers and fabric covered 703...?
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s3
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knightfly
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Scott, sorry you slipped by - I was up til 4:30 am finishing a drawing for another poster, and ran out of gas -
Here's a rough paint drawing of one mounting method - it's similar to what Ethan Winer has used for mounting his traps I think.
I'll have to catch the rest later today, duty calls... Steve
Here's a rough paint drawing of one mounting method - it's similar to what Ethan Winer has used for mounting his traps I think.
I'll have to catch the rest later today, duty calls... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
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knightfly
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Scott, as for mounting 703 directly, one method is to use "impaling clips" - here's a few links to explain -
http://web.ask.com/web?q=impaling+clips&o=0&qsrc=0
Gluing fabric - one way that works pretty well -
You need a flat table or surface that's larger than the panel you're working with. Line up the panel and cloth so that the weave of the cloth is parallel to the edge of the panel, cloth on the bottom, panel aligned on top of the cloth. Place some heavy weights on the panel to keep it from shifting. If you're REALLY using CONTACT cement, there are two ways to use it. One, you put it on wet and clamp one way or another - the other way, you wet BOTH surfaces, let each get "dry" to the touch, and CAREFULLY bring the two surfaces in contact with each other and (optionally) clamp for a while. Other people use spray adhesives by 3M, etc -
Anyway, you glue the ONE edge and let it cure long enough to have good strength - laying a heavy board on the joint, maybe even with extra weights, can give a tighter joint. Then, you stretch the cloth evenly across the panel and glue the OTHER long joint, again using a heavy board with extra weights to clamp. You will want to get some waxed paper (like the kind you use to wrao sandwiches) and put it between the glue joint and the weighted board, so it doesn't stick to the board.
Once these two joints are dry, you can repeat (and fold carefully) for top and bottom glue joints.
Don't make the mistake of gluing the whole mess to a plywood back, unless you're making a Gobo and want one side live, one side absorbent - fiberglas board works better when stood off the wall a few inches, and with NO BACKING other than the distant wall.
When you're mounting traps on walls, keep a few things in mind -
1 - If the wall is already on Resilient Channel, traps may overload the RC if you have more than two layers of wallboard already on them.
2 - If the wall has RC on that side, you CAN NOT mount the trap mounting rail directly to studs or you'll ruin the isolation of the wall.
3 - If you are mounting a trap hanging rail on a Resilient wall, you could mount the rail using toggle bolts - this will defeat the layers of wallboard on the RC on its own, so you would need to run a large bead of acoustic caulk around each hole in the wall, between the wall and the mounting rail, and then before you tighten up any of the toggle bolts squirt a generous amount of caulk into the hole in the mounting rail, so that when you tighten the toggle bolts you "repair" the break in sound barrier with caulk and solid wood.
If this is the route you take, try to make it so that the "bumpers" on the rear of the traps align with stud locations - this should tame any coupling between trap and wall by giving the trap a firmer place to rest.
That's about all I can think of for now, hope it helps... Steve
http://web.ask.com/web?q=impaling+clips&o=0&qsrc=0
Gluing fabric - one way that works pretty well -
You need a flat table or surface that's larger than the panel you're working with. Line up the panel and cloth so that the weave of the cloth is parallel to the edge of the panel, cloth on the bottom, panel aligned on top of the cloth. Place some heavy weights on the panel to keep it from shifting. If you're REALLY using CONTACT cement, there are two ways to use it. One, you put it on wet and clamp one way or another - the other way, you wet BOTH surfaces, let each get "dry" to the touch, and CAREFULLY bring the two surfaces in contact with each other and (optionally) clamp for a while. Other people use spray adhesives by 3M, etc -
Anyway, you glue the ONE edge and let it cure long enough to have good strength - laying a heavy board on the joint, maybe even with extra weights, can give a tighter joint. Then, you stretch the cloth evenly across the panel and glue the OTHER long joint, again using a heavy board with extra weights to clamp. You will want to get some waxed paper (like the kind you use to wrao sandwiches) and put it between the glue joint and the weighted board, so it doesn't stick to the board.
Once these two joints are dry, you can repeat (and fold carefully) for top and bottom glue joints.
Don't make the mistake of gluing the whole mess to a plywood back, unless you're making a Gobo and want one side live, one side absorbent - fiberglas board works better when stood off the wall a few inches, and with NO BACKING other than the distant wall.
When you're mounting traps on walls, keep a few things in mind -
1 - If the wall is already on Resilient Channel, traps may overload the RC if you have more than two layers of wallboard already on them.
2 - If the wall has RC on that side, you CAN NOT mount the trap mounting rail directly to studs or you'll ruin the isolation of the wall.
3 - If you are mounting a trap hanging rail on a Resilient wall, you could mount the rail using toggle bolts - this will defeat the layers of wallboard on the RC on its own, so you would need to run a large bead of acoustic caulk around each hole in the wall, between the wall and the mounting rail, and then before you tighten up any of the toggle bolts squirt a generous amount of caulk into the hole in the mounting rail, so that when you tighten the toggle bolts you "repair" the break in sound barrier with caulk and solid wood.
If this is the route you take, try to make it so that the "bumpers" on the rear of the traps align with stud locations - this should tame any coupling between trap and wall by giving the trap a firmer place to rest.
That's about all I can think of for now, hope it helps... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
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s3
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- Joined: Wed May 21, 2003 5:19 pm
Hi again,
I have 2 follow up questions.
1. Johns drawing for the front and rear absorber show 1/4" ply on the back. In your response you mentioned to leave the back uncovered. I am a little confused....?
2. What are the reasons you would use 703 over 705 and vice versa? Could you use 2" of 705 with 2" of 703 glued to it front to enjoy the benifits of both? Or does it not work that way?
Thanks again!
S3
I have 2 follow up questions.
1. Johns drawing for the front and rear absorber show 1/4" ply on the back. In your response you mentioned to leave the back uncovered. I am a little confused....?
2. What are the reasons you would use 703 over 705 and vice versa? Could you use 2" of 705 with 2" of 703 glued to it front to enjoy the benifits of both? Or does it not work that way?
Thanks again!
S3
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knightfly
- Senior Member
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- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
"Johns drawing for the front and rear absorber show 1/4" ply on the back. In your response you mentioned to leave the back uncovered. I am a little confused....? " -
My comments about not using plywood to back 703 were intended as part of the answer to your question about mounting "loose" 703 to the wall without a frame. Used this way as a basic absorbent, 703 works down to lower frequencies the farther away from the wall you mount it.
When used in a specifically designed trap, there are sometimes other goals. In that case, you should follow the design of the particular project.
As to using 703 or 705, that depends on the result you need - they are different densities and have different absorption characteristics. Here is the product spec sheet for the 700 series fiberglas products -
http://www.owenscorning.com/comminsul/d ... Series.pdf
you'll notice in the last table, that each type/thickness/facing option behaves differently at different frequencies - what/how you use which material will change the result you get.
What you do to treat different parts of a room should be part of a complete system-like approach - the final goal in order to build a good, neutral sounding room is to achieve as even a reverb time throughout the frequency range as you can - differing reverb times at different frequencies will color the sound in the room, causing you to make inappropriate mix decisions and/or tracking decisions.
The only sure way to avoid this problem is to build a room that has an even, smooth reverb decay time through the frequency range, so that changes you make in a mix are because of the mix, not the room. You accomplish this by combining different materials based at least partly on their absorption characteristics, so that the total absorption surfaces in the room balance out absorption through the frequency range.
As to mixing types of fiberglas, it would depend on your goal. As long as you don't block the second layer of material by using full coverage glue instead of just perimeter and a small spot in the center, the overall absorption should be somewhere near the average of the two types at each frequency band, based on total thickness of the whole laminated panel.
Also, the figures in this document only pertain to direct frontal sound waves - with shallower angles, sometimes the lighter types absorb better than the heavier ones.
Check out the absorption differences on the chart I linked to - be aware though, that I've spotted what I'm sure is a typo on the chart - the figure for 705 1" unfaced at 125 hZ should be .12, not .02 - check the surrounding numbers, and you see that the .02 figure just doesn't make any sense... Steve
My comments about not using plywood to back 703 were intended as part of the answer to your question about mounting "loose" 703 to the wall without a frame. Used this way as a basic absorbent, 703 works down to lower frequencies the farther away from the wall you mount it.
When used in a specifically designed trap, there are sometimes other goals. In that case, you should follow the design of the particular project.
As to using 703 or 705, that depends on the result you need - they are different densities and have different absorption characteristics. Here is the product spec sheet for the 700 series fiberglas products -
http://www.owenscorning.com/comminsul/d ... Series.pdf
you'll notice in the last table, that each type/thickness/facing option behaves differently at different frequencies - what/how you use which material will change the result you get.
What you do to treat different parts of a room should be part of a complete system-like approach - the final goal in order to build a good, neutral sounding room is to achieve as even a reverb time throughout the frequency range as you can - differing reverb times at different frequencies will color the sound in the room, causing you to make inappropriate mix decisions and/or tracking decisions.
The only sure way to avoid this problem is to build a room that has an even, smooth reverb decay time through the frequency range, so that changes you make in a mix are because of the mix, not the room. You accomplish this by combining different materials based at least partly on their absorption characteristics, so that the total absorption surfaces in the room balance out absorption through the frequency range.
As to mixing types of fiberglas, it would depend on your goal. As long as you don't block the second layer of material by using full coverage glue instead of just perimeter and a small spot in the center, the overall absorption should be somewhere near the average of the two types at each frequency band, based on total thickness of the whole laminated panel.
Also, the figures in this document only pertain to direct frontal sound waves - with shallower angles, sometimes the lighter types absorb better than the heavier ones.
Check out the absorption differences on the chart I linked to - be aware though, that I've spotted what I'm sure is a typo on the chart - the figure for 705 1" unfaced at 125 hZ should be .12, not .02 - check the surrounding numbers, and you see that the .02 figure just doesn't make any sense... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
-
s3
- Posts: 25
- Joined: Wed May 21, 2003 5:19 pm
Hi again,
I'm sorry, I don't mean to be a pain.....If I built one of Johns rear or front absorbers, how would you mount it? I am not seeing how in yourreply. Maybe I am misunderstanding something. It's back is a solid piece of ply and the directions say to mount directly on the wall. I assume this means no space like there is in the drawing you have for mounting plain 703 panels. Could you hang it like a picture with some heavy duty wire or cable, or is there abetter way? Also, on the drawing for the plain 703 mounting, how do you attach the piece of wood to the back of the 703? I was thinking of impaling clips except I don't think the poly that I bought to cover the insulation will handle being punctured very well. I could be wrong.
Thanks,
S3
I'm sorry, I don't mean to be a pain.....If I built one of Johns rear or front absorbers, how would you mount it? I am not seeing how in yourreply. Maybe I am misunderstanding something. It's back is a solid piece of ply and the directions say to mount directly on the wall. I assume this means no space like there is in the drawing you have for mounting plain 703 panels. Could you hang it like a picture with some heavy duty wire or cable, or is there abetter way? Also, on the drawing for the plain 703 mounting, how do you attach the piece of wood to the back of the 703? I was thinking of impaling clips except I don't think the poly that I bought to cover the insulation will handle being punctured very well. I could be wrong.
Thanks,
S3
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knightfly
- Senior Member
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- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
Scott, the mounting method I drew earlier WAS for a complete "trap", not for un-mounted 703 - My omission in not stating that explicitly. If you were to use that method for mounting, and unless the back of your trap is heavy plywood (like 3/4" or more) you would need to plan ahead for mounting, and fasten the beveled cleat to the back of the trap BEFORE you finish the trap's insides and seal it up. For a 24" wide trap up to 8 feet long, assuming that the beveled cleat on the rear is 1-1/2" thick, I would use #10 screws that are long enough to penetrate the cleat by at least 1", preferable 1-1/4", and I'd use at least 6, preferably 8, spaced evenly in two rows - 3-4 across the top of the cleat 3/4" to 1" from the upper edge of the cleat, and 3-4 more screws the same distance from the lower edge of the cleat. Run a bead of acoustic sealant along the two lines of screws between the back and the cleat before putting in the screws, just to avoid any unwanted vibration. Use the same method to fasten the lower "bumpers", and you can use contact cement to fasten any rubber/neoprene to the bumpers.
Even though the above drawing was intended for wood-framed and backed "traps", you could also use the same idea for mounting un-framed 703 - there is no real need to wrap the side of the 703 that's away from you, once it's in place you won't get any fiber problems unless you try to "blow down" the studio with a high pressure air hose.
You could wrap the FRONT of the 703 in your plastic (I hope it's really thin, like those thin painter's drop cloths) and stop the plastic with just 2-3" of overlap on the rear of the panel - then wrap with your cloth, as I explained earlier, being careful to keep the rear side of the fiberglas as smooth as possible. Once this is all dry, you could then get some long screws (about 3/4" longer than your cleat is thick) and put them in the same pattern I outlined above for cleats on wood traps - only this time, run them through the cleat starting from the side of the cleat that will face the wall, and drive them FLUSH with the rear of the cleat so they stick out the front of the cleat - this will give you 6 or 8 "mini-impaling clips" sticking out the front of the cleat - keep the screws at least 4" from the edge of the 703. then, smear the whole front of the cleat (the one that's getting GLUED to the rear of the 703) with EPOXY, as well as putting some epoxy on the back of the 703 where the cleat goes, and then IMPALE the 703 over the protruding screws and place a weight on the whole thing til the epoxy cures (read the label, epoxies are not all the same)
Doing the un-framed 703 this way will keep it from slipping should the epoxy not have good "shear" strength. It will also, if you make the wall portion of the mounting rail one continuous piece, let you move your traps/absorbent around on the wall, or even remove them if you like, to "tune" your room.
For a trap that has a back as part of the trap, having an inch or two between the wall and trap won't hurt the effect of the trap, but it may reduce the STC of the wall slightly at that point (which affects the whole room's sound proofing slightly) - this can't be helped unless you're willing to forego acoustic treatment entirely, so don't worry about it.
The space behind the un-framed 703 will only HELP its performance... Steve
Even though the above drawing was intended for wood-framed and backed "traps", you could also use the same idea for mounting un-framed 703 - there is no real need to wrap the side of the 703 that's away from you, once it's in place you won't get any fiber problems unless you try to "blow down" the studio with a high pressure air hose.
You could wrap the FRONT of the 703 in your plastic (I hope it's really thin, like those thin painter's drop cloths) and stop the plastic with just 2-3" of overlap on the rear of the panel - then wrap with your cloth, as I explained earlier, being careful to keep the rear side of the fiberglas as smooth as possible. Once this is all dry, you could then get some long screws (about 3/4" longer than your cleat is thick) and put them in the same pattern I outlined above for cleats on wood traps - only this time, run them through the cleat starting from the side of the cleat that will face the wall, and drive them FLUSH with the rear of the cleat so they stick out the front of the cleat - this will give you 6 or 8 "mini-impaling clips" sticking out the front of the cleat - keep the screws at least 4" from the edge of the 703. then, smear the whole front of the cleat (the one that's getting GLUED to the rear of the 703) with EPOXY, as well as putting some epoxy on the back of the 703 where the cleat goes, and then IMPALE the 703 over the protruding screws and place a weight on the whole thing til the epoxy cures (read the label, epoxies are not all the same)
Doing the un-framed 703 this way will keep it from slipping should the epoxy not have good "shear" strength. It will also, if you make the wall portion of the mounting rail one continuous piece, let you move your traps/absorbent around on the wall, or even remove them if you like, to "tune" your room.
For a trap that has a back as part of the trap, having an inch or two between the wall and trap won't hurt the effect of the trap, but it may reduce the STC of the wall slightly at that point (which affects the whole room's sound proofing slightly) - this can't be helped unless you're willing to forego acoustic treatment entirely, so don't worry about it.
The space behind the un-framed 703 will only HELP its performance... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...
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knightfly
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- Joined: Sun Mar 16, 2003 11:11 am
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By "rear mounting wood", are you referring to the back of the trap or the beveled cleats you attach to either the wall or the trap? For cleats, you would probably be better off with something that has some "grain structure" to it, which neither particle board nor MDF has. I'd use at least OSB, (Oriented Strand Board) or Wafer Wood (the stuff that looks like somebody took broken pieces of wood and smashed them together, which in fact they did) but preferably solid wood, such as a length of 2x4 with one side beveled as shown.
For the backs of traps, especially those that will be hung, I'd use something lighter like plywood. It's not only lighter, but it's stronger as well, and is less likely to allow screws to pull through... Steve
For the backs of traps, especially those that will be hung, I'd use something lighter like plywood. It's not only lighter, but it's stronger as well, and is less likely to allow screws to pull through... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...