I've found some rigid fiberglass, now what?

goskers · « **on:** 31 Jan 2005, 08:35 pm »

Hi all,

I have been looking around for some rigid glass and have finally sourced some. I have the options of 2 or 4" OC 703 or some 3" from a different company. I am planning on using some of the 4" in all four corners but am not sure what the best options are for the ceiling corners and upper wall edges.

What do you recommend? I have been reading some of Ethan Winer's recommendations so I am placing my corners and ceiling edge points as number 1.

Thanks

jermmd · « **Reply #1 on:** 31 Jan 2005, 09:04 pm »

Where'd you find the fiberglass panels? I can't find any by me.

Joe M.

goskers · « **Reply #2 on:** 31 Jan 2005, 09:07 pm »

I found mine by calling all the insulation suppliers in the phone book. One place had both 2,3&4" while another had 2" only. Just look under insulation supplier in the yellow pages and start calling.

goskers

Red Dragon Audio · « **Reply #3 on:** 1 Feb 2005, 04:16 am »

Quote from: goskers

Hi all,

I have been looking around for some rigid glass and have finally sourced some. I have the options of 2 or 4" OC 703 or some 3" from a different company. I am planning on using some of the 4" in all four corners but am not sure what the best options are for the ceiling corners and upper wall edges.

What do you recommend? I have been reading some of Ethan Winer's recommendations so I am placing my corners and ceiling edge points as number 1.

Thanks

You are on the right path. Set them up in the corners and ceiling corners like you said. That should provide you with plenty of improvements. After that, maybe treat first reflection points if they are a problem and in the center of walls if there is echo or still lingering bass problems.

zybar · « **Reply #4 on:** 1 Feb 2005, 04:23 am »

Quote from: goskers

Hi all,

I have been looking around for some rigid glass and have finally sourced some. I have the options of 2 or 4" OC 703 or some 3" from a different company. I am planning on using some of the 4" in all four corners but am not sure what the best options are for the ceiling corners and upper wall edges.

What do you recommend? I have been reading some of Ethan Winer's recommendations so I am placing my corners and ceiling edge points as number 1.

Thanks

Go 4" on thickness and follow Ethan's recommendations. Your system will sound notiiceably better.

George

ooheadsoo · « **Reply #5 on:** 1 Feb 2005, 05:22 am »

Rather than 4" of 3lbs/pcf, I would go for 2" of 5-6lbs/pcf. Much more space efficient.

Here's what I did for my 2" 3lb/pcf panels. If I were to do it again, I'd go with the 5-6lb./pcf.

http://www.audiocircle.com/index.php?topic=11639&

birdwizard · « **Reply #6 on:** 1 Feb 2005, 05:36 am »

What about these foam cornices?

Are they of any acoustical value?

http://www.rensup.com/Categories/Cat-681.htm

Red Dragon Audio · « **Reply #7 on:** 1 Feb 2005, 05:02 pm »

Quote from: ooheadsoo

Rather than 4" of 3lbs/pcf, I would go for 2" of 5-6lbs/pcf. Much more space efficient.

Here's what I did for my 2" 3lb/pcf panels. If I were to do it again, I'd go with the 5-6lb./pcf.

http://www.audiocircle.com/index.php?topic=11639&

but if you can get 4" thick with the higher density (4-6PCF) than go with that for bass traps.

the lower density stuff will absorb/trap higher frequencies much better.

ooheadsoo · « **Reply #8 on:** 2 Feb 2005, 01:50 am »

Personally, I would go for the fiberglass pipe and stuff that with fiberglass rather than go for a large 4" thick panel, but I suppose it's left up to taste. For a dedicated bass trap, I think the tube is more space efficient. For something you can relocate around the room, I guess the panels would be more handy. Though a 4" panel is kinda thick IMO.

Red Dragon Audio · « **Reply #9 on:** 2 Feb 2005, 05:52 am »

Quote from: ooheadsoo

Personally, I would go for the fiberglass pipe and stuff that with fiberglass rather than go for a large 4" thick panel, but I suppose it's left up to taste. For a dedicated bass trap, I think the tube is more space efficient. For something you can relocate around the room, I guess the panels would be more handy. Though a 4" panel is kinda thick IMO.

Well 2" vs 4" thickness is silly if you think about it. Both panels are still 4ft high by 2ft wide. So visually they're about equal in terms of space taken up on the wall. But the 4" thick panel is probably a good bit better in terms of bass absorbtion.

Tubes look cooler and I've often recommended them but after contemplating what Ethan W. always say; GREATER AREA COVERAGE IS MOST IMPORTANT.

Tubes have more compressed fiberglass but cover the same amount of area on the wall. I guess I should ask Ethan but does the back of the fiberglass tube really do anything in terms of bass absorbtion? I'm sure it does at some frequency but it seems like all of Ethan's recomendations are to pull the panels out at least 4" from the wall. A tube would have the front of it's mass far enough out but the back half of it in the corner would be pretty close to the wall...so would it even work as well if at all?

I think what would be the best is to get a nice large diameter, thick fiberglass tube and cut it into fourths.

Quarter Rounds a la ASC

If you got those say 6" thick and 5-6PCF, covered them in fabric and set them in the corners, taht would look great, work extremely well in a floor to ceiling situation, and maybe save money since you would be cutting up one tube into fourths.

I'm going to look into that now damnit!

I do like the clean round cylinder look:

Here's a little adaptation on my last drawing. Obviously things are not quite to scale but it gives you an idea of what I mean. I don't mean to use flat panels behind the quarter rounds though. I just left those in there for reference.:

ooheadsoo · « **Reply #10 on:** 2 Feb 2005, 06:11 am »

It may not seem like it, but 4" really does make an imposing presence. My $0.02.

Red Dragon Audio · « **Reply #11 on:** 2 Feb 2005, 06:39 am »

Quote from: ooheadsoo

It may not seem like it, but 4" really does make an imposing presence. My $0.02.

Ok now this will take a little more effort than just hanging the panels up but here goes. Get some kind of table saw and set it at the proper 45deg angle so you can make two long cuts down the length of the 4" thick fiberglass panels.

This way you won't see the thick edges of the 4" panels which are still the same dimensions as the 2" thick panels in Width and Length. This way they can't be more visually imposing anymore.

Now that's a trick idea ain't it?!

ooheadsoo · « **Reply #12 on:** 2 Feb 2005, 07:40 am »

I did think of that but...it does take quite a bit more effort and a rather large piece of equipment

I don't think the fiberglass is rigid enough for a clean cut, or maybe any cut at all, but I suppose the surrounding material will disguise it.

ToddSTS · « **Reply #13 on:** 2 Feb 2005, 02:12 pm »

I had problems cutting 1" rigid fiberglass with a blade. It cuts but not very cleanly. Be careful with a power saw and rigid fiberglass. I would think that would create all kinds of little irritating fibers for you to breath in. I use a utility knife.

Instead of and angle cut why not just get two 2" panels or four 1" panels and stair step them down behind the front panel? Just an idea. I have some 2" panels that I haven't done anything with yet. I will see how think they look when I make a 4" panel. I may end up cutting the rear panel a little thinner to make it snug into the corners.

OT: Heavystarch, any news on the autoformers?

Todd

Red Dragon Audio · « **Reply #14 on:** 2 Feb 2005, 05:42 pm »

VERY GOOD POINT ooheadsoo! A table saw is NOT the best way to go. It was late when I wrote that and I was only thinking of the end goal.

Someone just asked in another post about how to cut acoustic foam because the manufacturer said to use turkey cutters. NathanM agreed it was a good way to go and I've seen pro upholsterers use something like turkey cutters (reciprocating blade tool) to cut what looked to be layers of carpet padding to form custom seats in cars.

With the turkey carves it will go a little slower but it won't kick out fiberglass particulates. Just do it outside with goggles and a mask and you'll be fine. Also you are right that the fabric will cover those edges and they will be against the wall anyway so they won't be seen.

The Quarter Round idea I painted out there would make cutting much easier and aesthetically might actually look better. Curves are easy on the eyes. All rigid fiberglass pipe insulators come cut in half already so you'd only have to do two cuts.

**ToddSTS** No news as of yet; they're just testing the differences between EI core versions versus Toroidal core versions.

goskers · « **Reply #15 on:** 4 Feb 2005, 01:09 pm »

I had thought of the 45* idea. I like it but I am not real sure as to how rigid this stuff is yet. If you can drive a screw into it like wood then you could hang all these panels similar to pictures. That would be great and easy as well.

I am going to do 4" in the corners of which I will try to source some 6lb density and will do 2" everywhere else.

Can someone please explain what effect dampening the first reflections is likely to have on overall acoustics?

Thanks

Ethan Winer · « **Reply #16 on:** 4 Feb 2005, 04:57 pm »

Goskers,

> Can someone please explain what effect dampening the first reflections is likely to have on overall acoustics? <

It improves imaging - the ability to discern left-right placement in the stereo field - and also improves clarity.

--Ethan