[nathanm]

No eating?  Oh shit, I thought this stuff was cotton candy!  Aaargh! Dammit!  Well, that explains the burning, itchy tongue.

I think it goes without saying that any large, soft and or heavy absorptive objects make for useful sonic traps.  I dunno about you, but I'd be more inclined to stack fiberglass in my room than schlep around a bunch of heavy punching bags.  Neither are particularly attractive and would require some disguising, but the punching bags seems rather clunky, and why pay for the canvas, chains etc. when they aren't really necessary?  But I can think of at least one person who would embrace having a row of punching bags piled up against the walls!

[ooheadsoo]

This is a unique solution and I think it deserves credit for providing a potential solution for people who have multipurpose rooms.

[azryan]

double post -oops.

[azryan]

I think he gets credit. I mean no one said the punching bags didn't work right? In fact I think everyone agrees that they believe they do have a real effect.

Did you get your 'Pipe Insulators' from a Knauf retailer? How much did you pay for them?

Ahh.... crap. I forget how much. Not more than two punching bags though and I've got 4 traps that are all 7.5' tall pretty much covering the entire corners. I bought 'em from an insulation werehouse in town.


I don't know that the sheets you bought will do much for bass in anything in the corners. I believe it needs to be a sealed deal or a solid thick mass.

They should make perfect broadband reflection point absorbers though. Just wrap in a nice light cloth and should look good too and be easy to hang by invisible fishing line or something like that.

I was just joking about the saftey hazzard of fiberglass.

Actually I have never heard of homes that don't use fiberglass insulation in the walls.

Oh there are other things. cellulose (basically shredded newspaper I think) and my room addition is actually made of 'perform panel' which is 15% cement/85% polystyrene (Dixie cup foam beads) made into 10" thick blocks with holes for rebar and poured cement.

Only a little more than normal walls and FAR better. Wish my whole place was made of the stuff. Does echo like a cement basement though but with carpet, furniture, and some little room treatments my room's pretty much dead (don't want it totally dead though).

sorry... that's off topic. Now back to the topic...

How many boxing gloves do you think it'd take to treat all reflection points?

[Rob Babcock]

This is just a guess, Azryan, but I suspect he plans to cut the sheets up & glue them together in the shape of a box (coffin type shape).  At least that's what I've been wanting to do.

[Red Dragon Audio]

Hey Guys,

Actually, Ethan Winer just says to place them across the corners but sealing is not necessary.  Ethan does have a design that must be perfectly sealed though.

I wonder if sealing the tubes you have AZ makes them into sort of a hemholtz resonator that still absorb bass?

I'm no acoustic engineer so I am just thinking outloud...sort of...on the internet.  

 

[azryan]

Oh really? I hadn't thought of that.  Maybe he'll post to confim that's his goal.

That seems like a waste to me though if you could just buy premade tubes.

It might not be an option for people though but I'd think most larger towns should have this available?

If you're going to make a 3D shape out of flat fiberglass... mighht be a better idea to make triangular traps than rectangular.

And then... if you're going to do that, then you might go the way like PS Audio's room (not that I'm a fan of PS Audio at all) where they took some wood like plywood maybe and closed off the corners (making a triangular space) and just packed it with fiberglass.

They put bookshelves in front of that I think and packed the shelves full with randomly assorted sized books to make a diffusion surface, but you could also go with just adding maybe a sheet of drywall over plywood and painting to match the room?

You'd be able to hang pictures or junk like that on it too. Might be too weird, but might be WAF passable and would make great corner traps.

But back to boxing gloves...

[azryan]

I wonder if sealing the tubes you have AZ makes them into sort of a hemholtz resonator that still absorb bass?

That's what they were called when I read about this idea online. I didn't make it up or anything. Someone else's. I'm just passing it on.

I think I tried reading the def. of hemholtz resonators and it didn't seem clear to me but the tube traps trapped and chopped up the bass buildup so that was good enough for me to tell others that it works.

So is Ethan saying you can just use a flat sheet in a corner ('cuz that seemed wrong to me but I'm no expert) or are you packing the whole corner up or what?

Did he say what they'll absorb down to? Like down to the true subwoofer range?

[MaxCast]

I think Eathen says that some of the sound gets absorbed as it passes through and absorbed further as it hits the wall and comes back out.  I don't think he claims them to be "bass traps" but rather broad band absorbtion.  Better than foam because it covers a wider frequency range.

[Gordy]

Hi all,

FYI, here's a rather generic MSDS for insulation type fiberglass...  I don't see where it says not to eat it though

http://www.guardianfiberglass.com/printouts/eng_msds2.htm

hope it helps!

[Red Dragon Audio]

AZ - Maxcast,

I think if you mount them in the corner from floor to ceiling they will act as bass traps...how low they'll go....nobody knows...round and round we go!

No Ethan never measured this kind of trap and I won't be able to really do any true measurements either.  Don't know how really...guess I could measure the bass response before and after treatment with my ratshack meter.

I think Maxcast is right saying it is a broadband trap that would probably go up into the lower midrange to midrange area of absorbtion.

AZ I think you are right that they would absorb more bass if I were to stuff more fiberglass behind them like PS Audio did with their book cases.

There will be 6 panels that measure 2'x4' which I will probably use just in the corners and perhaps two panels right behind my speakers or in the middle of the wall.  Much experimenting will be going on.


I will report back on how things turn out in my room once they are in place.



Does anyone read my posts and think;

"GEEEZ!  Does this guy even know how to write a coherent thought?!!"  I just write thoughts as they come to mind and get tired of thinking if they make sense....damn I'm lazy.

[azryan]

Yeah Maxcast that description sounds like what would just be a broadband acoustic reflection absorber -which pretty much means everything from top down to maybe the bass range but not really much if anything in the actual 'bass range' (meaing say ~160Hz on down/ ~bottom 3 octaves).

heavystarch,

I think even going floor to ceiling you won't be making 'bass' traps so much. Maybe not at all even.

Fiberglass if it's uncovered (or covered with breathable light cloth) will absorb  higher and higher freq. better and better but there shouldn't really be much of that from your speakers hitting the room corners compared to the actual 1st reflection points on your walls/floor/ceiling.

I find it to work best when thinking about room treatments to consider the 'bass range' (~160Hz on down) and 'mids/highs' (160Hz to 20kHz+) as two totally diff. animals.

The old line about imagining bass like ocean waves and the rest like ping pong/pool balls.

With bass being best treated in the corners and the rest treated at reflection points based on the output of whatever speakers you've got and how they're aimed.

It seems like you're looking to treat your corner bass buildup with a more upper range reflection type solution.

It might have some good effect though and doubt it'd have any bad effect pre se, but I just don't think it's sounding like it'll be an actual bass trap for you.

And then to consider that you only really need to treat the problems you have.

If you have no real room problems... you're 'done' without doing anything.

Rare is that the case though, but some people think you always need to fully deck out a room full of treatments before it's 'right' and that's not always true.

[Red Dragon Audio]

This is just what I remember from my reading:

2" thick 6.00PCF FSK insulation boards of fiberglass when used at right-tri-corners and corners will absorb bass down to about 40Hz from what I extrapolated at www.realtraps.com.  I got this info from measurements on www.realtraps.com ...basically I looked at the dimensions of the traps, their acoustic ratings and then I looked for the same kinds of things from Knauf's product line.

That's how I got to the point of using 2" thick 6.00PCF panels for bass absorbtion (not really traps.  Absorbtion works off the idea that the bass energy is absorbed into the panel and converted into low level heat).  Heavier, 6.00PCF, insulation panels are better at absorbing low frequencies than lighter fiberglass which absorbs higher frequencies.

Then I just looked at how they suggested using the "Real Traps" in a room.  I figure mine ought to do the same thing. http://www.realtraps.com/placing_mt.htm

Since I am not buidling any resonators my bass absorbtion devices need not be sealed...not unlike the quick 'n' dirty bass absorbtion you get from just a big bag of the pink stuff or the punching bag suggested herein.  Their mass of stuffing is what is absorbing the bass.

Of course I would get more bass absorbtion if I stacked my pieces together like the "Mondo" traps.  So i would have 4" or 6" thick panels.

slightly off bass topic
You are right to say that my panels will be more efficient at absorbing upper bass/lower mid/ midrange tones...but since I will be placing them in the corners, their job will be to absorb bass.

If I place them at the first reflection points and other ares to treat slap echo that's what they'll treat.  But I will buy other panels from the Knauf dealer for that kind of thing.  Probably 2.25PCF 2" thick panels as they are much cheaper than the 6.00PCF and they would work better still for midrange-upper frequencies.

[errivera]

Azryan, I don't mind that we strayed from the original topic, I was just hoping to get someones personal opinion (after having tried it) regarding the bag. Instead, fiberglass became the main topic, that's cool.

I think you read too much into what I was saying. I have a pretty good understanding of the Physics of Acoustics and was just trying offer viable alternatives not give a discourse.

PS: Remember, not too long ago (historically speaking) the insulation of choice was asbestos. It has similar properties of fiberglass and might be better at converting sound into heat.