I've been thinking about putting up some difussors in some spots around the
studio. I've noticed fiberglass sheets used for roofing of sheds and such
that's common in building supply stores. It comes in 4x8 sheets in different
colors and is sine wave shaped, maybe 6 waveforms or such to a sheet. Has
anyone ever looked into using this material for diffussion? It's certainly
cheap and easy to use.

Henry
Pittsburgh, PA

I've been thinking about putting up some difussors in some spots around
the
studio. I've noticed fiberglass sheets used for roofing of sheds and such
that's common in building supply stores. It comes in 4x8 sheets in
different
colors and is sine wave shaped, maybe 6 waveforms or such to a sheet. Has
anyone ever looked into using this material for diffussion? It's certainly
cheap and easy to use.

Are you looking to have diffused reflection? Most people are looking for
diffused absorption, using corrugated foam panels.

(HenryShap) wrote in message ...
Reflection. I have plenty of absorption, auralex 2" foam and some heavy theater
curtains mostly. It's getting rather dead in here which is why I looking to
make some diffusors.


Are you looking to have diffused reflection? Most people are looking for
diffused absorption, using corrugated foam panels.

Do you have the Master Handbook of Acoustics? There's a lot of really
good information in there about diffusion of sound. The problem with
the corrugated sheets you mention is that they'll only work for a
narrow band of frequencies which will be related to the depth and
width of each well. The professionally made diffusors use a sequence
of varying well depths that are based on prime numbers so as to have a
wide band of frequencies being diffused. Look into it further before
trying those panels you mentiond. -Paul

In article , "Mark T. Wieczorek"
wrote:

Well... It's not very scientific, but can't you get a sense of what it
sounds like by standing in front of it and clapping your hands?

Sounds like a question for Ethan Winer.

Regards,
Mark

Not really. Hand claps are not wide enough bandwidth nor are they
sustained enough to really get the low end excited, so you are only
going to get a small picture of what the item's response will be under
the conditions present (a transient sound of a limited frequency range
in that particular room). Diffusion works in conjunction with absorption
and reflection in a well designed room, not to mention bass trapping
(part of absorption in a general sense, but a subject unto itself) and
it's design, use, and placement in a particular room is the result of
analyzing (or predicting) complex interactions. This isn't to say you
always need to take the expensive and complex route. Each case has it's
own criteria.

Diffusion can be as simple as an irregular surface if you aren't looking
to treat a specific frequency band, don't care much about where or how
the sound propagates, and just want to break it up a bit to get
something a little more interesting in the mids and highs. On the other
hand, it can be quite complex depending on your goals or requirements.
The construction and placement can vary quite a bit. Do you want 2D or
3D? Do you want an even response over a wide frequency range, or will
something narrower suffice? How low do you need it to go? Is it
something simple like flutter that you want to control without deadening
the room, or something more substantial? Do you want the sound to
disperse evenly, or is some directionality OK, or even preferred?

You could build a very large diffractal like the one at the back of
Gateway Mastering (one example among many) that will diffuse bass along
with mids and highs, but it's huge, heavy, somewhat complicated, and
expensive. If you want affordable 3D for mids and highs, some light
plastic "skylines" may do the trick. Clapping your hands in front of the
skylines vs. the large diffractal at Gateway won't really tell you what
they are doing. Nevertheless, simple, unscientific, and uneven diffusion
can still be an enhancement to a project studio. Take the approach
appropriate to your situation and budget, but be reasonable about what
it will and will not accomplish.

--
Jay Frigoletto
Mastersuite
Los Angeles
www.promastering.com

Henry,

I have plenty of absorption, auralex 2" foam and some heavy theater
curtains

How big is your room? And is this for a studio room or control room? Small
rooms are not really suited for diffusion.

As you discovered, too much mid/high absorption is not good either because
it kills all ambience.

--Ethan

You're right, I was being overly simplistic, but if the guy's considering
buying some roofing material from home depot and uses that egg carton foam
for "deadness", I guessed he didn't have the time, money, or inclination to
get the best he can get.

Bass probably travels right through that wavy aluminum stuff, but I figured
he only needed it to be "good enough for rock n roll." Also, bass travels
right through that egg carton foam stuff too.

Regards,
Mark

--
http://www.marktaw.com/

http://www.prosoundreview.com/
User reviews of pro audio gear

The main record room is around 12.5x15 with a 9' ceiling. It has a grand piano,
couch, fireplace, curtains in the room proper. That room is not too bad sound
wise.

There's an entrance way right off of it that's 12.5x6.5, it's where I place the
drums. That's where I was looking for some diffusion. There and in some other
strategic spots.

The curtains I have are heavy theater curtains along with aurelex 2" wedge cut
foam. No egg cartons here. I record jazz/acoustic mostly.

I just checked out the Master Handbook of Acoustics out of the library. Theres
some info in the diffusion section that looks promising. I have an earlier
version of his Home+Small studio book. That doesn't have as much info as the
lastest Acoustics edition. Thanks for that suggestion.

I'm now looking into maybe making some wooden diffusors. There's an article in
the latest Professional Sound (which I just saw at Borders' for the 1st time. I
think it's a canadian mag) about Maison de Musique. The difussors there look
very easy to make and portable.


Henry
BigShotRecording.com



How big is your room? And is this for a studio room or control room? Small
rooms are not really suited for diffusion.

As you discovered, too much mid/high absorption is not good either because
it kills all ambience.

Henry,

I'm now looking into maybe making some wooden diffusors.

That's probably overkill for a room so small. If your goal is to avoid
flutter echoes you could just place plywood against the wall(s) at an angle.
The wavy stuff you describe might help too, but the waves may not be deep
enough to do as much good as angled plywood.

--Ethan

(HenryShap) wrote in message ...
I've been thinking about putting up some difussors in some spots around the
studio. I've noticed fiberglass sheets used for roofing of sheds and such
that's common in building supply stores. It comes in 4x8 sheets in different
colors and is sine wave shaped, maybe 6 waveforms or such to a sheet. Has
anyone ever looked into using this material for diffussion? It's certainly
cheap and easy to use.

I had wondered about that same application years ago, but those
sheets are not exactly "cheap", certainly not cheap enough for
me to try it just to see if it would work. Still, I had thought
that if I used them, I would bow them out in polycylindrical
diffusor fashion. Now that it appears you're headed in other
directions, you might still find just enough motivation to buy
a couple to try it this way somewhere in your room, or perhaps to
suspend some from the ceiling by the corners to get some "droop".
Even thin plexiglass might be useful in that configuration, and
has the advantage of letting any ceiling light source remain
unblocked. I would just guess that these things would require
a lot of patience in experimentation to get the best placement
and angle, etc. In conclusion, since I really don't know what
I'm talking about, please let us know what you end up doing and
what you try along the way (and how it works or didn't work).

--
Keith W Blackwell

In article writes:

I had wondered about that same application years ago, but those
sheets are not exactly "cheap", certainly not cheap enough for
me to try it just to see if it would work.

You want cheap diffusion? Try large plastic salad bowls. Stuff them
with Fiberglas so they don't ring like bells. Paint 'em silver for
that "space ship held together with huge rivets" look.



--
I'm really Mike Rivers - )

"Ethan Winer" ethan at ethanwiner dot com wrote in message ...
... Small rooms are not really suited for diffusion.

How so? It seems to have helped the imaging in my too-small control
room, and I've seen it applied in small vocal booths and practice
rooms and such. If anything, I'd think a small space needs diffusion
even more than a large space, so as to spread out the reflections in
time and give the illusion of a larger space.

(HenryShap) wrote in message ...
I've been thinking about putting up some difussors in some spots around the
studio. I've noticed fiberglass sheets used for roofing of sheds and such
that's common in building supply stores. It comes in 4x8 sheets in different
colors and is sine wave shaped, maybe 6 waveforms or such to a sheet. Has
anyone ever looked into using this material for diffussion? It's certainly
cheap and easy to use.

Is that six cycles across 4 feet? If so it probably won't do much to sound
below about 1K, but might be pretty effective above that. If the stuff is
flexible you could get some lower frequency diffusion by bending it.
Sounds like pretty cheap experiment,

"Mike Rivers" wrote in message
news:znr1058286128k@trad...

You want cheap diffusion? Try large plastic salad bowls. Stuff them
with Fiberglas so they don't ring like bells. Paint 'em silver for
that "space ship held together with huge rivets" look.
--
I'm really Mike Rivers - )

Oh man, you just flashed me back a few years to when we used a big stainless
steel salad bowl with a bit of water in the bottom of it as SF sound FX.
Hit the bowl with something, and swirl the water for the modulation.
Compress to bring out the weird dissonant ringing, add some delay....
Beautiful.
--
John Cafarella
End Of the Road Studio
Melbourne, Australia

Greg,

How so?

The minimum recommended distance between your ears and a diffuser is
something like ten feet. I'm not saying you didn't get pleasing result in
your small room. But in small rooms absorption is generally a better choice
to keep imaging focused. Some of the diffusion experts here can probably
elaborate on this better than I can.

--Ethan