sound stage was Re: Digest Number 9

Archives of the acoustics mailing list

sound stage was Re: Digest Number 9

Postby Dan Nelson » Tue Feb 10, 2004 5:20 am

From: Smitty <smitty@x?.xxxx
Date: Sun Oct 31, 1999 1:42 pm
Subject: Re: Digest Number 9

I'm a multi-media producer with a background in video production and commercial/
industrial photography. I am faced with attempting to quiet down our big-box
photo
studio space so that we can do some video work. It's a warehouse condo situation
and we can't get it absolutely quiet, but we are used to working on location,
so we
can accept some background noise and work around it.

The room is about 30 by 50 with a 14' ceiling. And yes, we do have a drive-in
door... I am looking for recommendations for large sheets of acoustic material
that
we can mount on the walls and hang from the ceiling to kill some of the bounce
and perhaps some sort of large flexible panels that we might be able to piece
together to make a removable, hanging cover for the door.

I imagine for sophisticated acoustic folks, the solution here would be to
move...
However, the lease and the budget don't allow it, so I'm hoping that there will
be
some sort of cost-effective alternative to get us to a point where we can avoid
building little caves with the sound blankets we use on location...

I've looked at some of the sites recommended at <studiotips> but it is difficult
for me to sort out the options. Any suggestions would be appreciated.

Thanks,

George Smith
Director of Photography
BMI Studios
<smitty@b...>
Last edited by Dan Nelson on Tue Feb 10, 2004 5:33 am, edited 1 time in total.
Dan Nelson
 
Posts: 629
Joined: Sat Jan 31, 2004 2:52 am

sound stage was Re: Digest Number 9

Postby archive » Tue Feb 10, 2004 5:32 am

From: Dan Nelson <dprimary@e...>
Date: Sun Oct 31, 1999 10:55 pm
Subject: sound stage was Re: Digest Number 9

2' owens corning 703 mounted to the walls with fabric stretched over it would
would
work very well and be one of the most cost effective

What about building some second hinged doors just inside the rollup? door, then
you
can get a good seal around the door. The basic idea is a pair of hinged walls
with
seals. How big is the door and what type is it? The big problem with those
rollup
doors is there is no way to seal them and if the wind is blowing they rattle.

Dan Nelson
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Tue Feb 10, 2004 5:39 am

From: SRF7@a...
Date: Sun Oct 31, 1999 11:43 pm
Subject: Re: Digest Number 9

In a message dated 10/31/99 9:00:15 AM Eastern Standard Time, smitty@u...
writes:

<< And yes, we do have a drive-in
door... I am looking for recommendations for large sheets of acoustic
material that
we can mount on the walls and hang from the ceiling to kill some of the
bounce
and perhaps some sort of large flexible panels that we might be able to piece
together to make a removable, hanging cover for the door. >>

If the existing garage door is not of substantial construction then a good
place to start might be the purchase of a top-of-the-line insulated
replacement door which will give you something hefty and stable to work off
of... in the long run a new room is probably needed as I just can't see
getting the required air seal around the edges of a roll up door that would
give acoustic isolation from the outdoors without going to a ridiculous
amount of trouble.

How about building a wall behind the door.. and paint a garage secene on it
;-]

Good Luck

Scott R. Foster
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:43 am

From: Smitty <smitty@x?.xxxx
Date: Mon Nov 1, 1999 1:27 pm
Subject: Re: Digest Number 10

Dan Nelson and Scott Foster,

Thanks for the feedback on the "big box" problem.

The garage door is 12' high and 10' wide, but separate swinging doors are not
out of the
question. Fortunately the space does not have to be absolutely silent. I like
the idea of
the new wall too, but maybe I'll paint a scene of Jersey City instead of the
garage
door ;-) ...

A few more questions if you have the time...

Does the type of fabric on the acoustic panels make any difference, and is
there a way to
estimate how many panels I will need for a given space, or is it just trial and
error?
And should panels be suspended from the ceiling? I have seen photos of panels
hanging
vertically in large spaces and I wondered if either horizontal or vertically
suspended
overhead panels would be effective.

If there are basic resource books for this sort of thing, I'd appreciate any
recommendations.

Thanks for your help.

George Smith
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:43 am

From: Mark Plancke <soundtch@x??x.xxxx
Date: Mon Nov 1, 1999 2:34 pm
Subject: Re: sound stage was Re: Digest Number 9

At 03:55 PM 10/31/99 -0700, you wrote:
>From: Dan Nelson <dprimary@e...>
>
>2' owens corning 703 mounted to the walls with fabric stretched over it
>would would
>work very well and be one of the most cost effective
>

Is 2" enough? I thought you had to go 4" 703 to get
broadband absorbtion? How far down does 2" 703 go
to? I'm asking because I've got my live room to treat
very shortly. It's 20x19x8 so I was going to put up
4" frames, stuffed with 703. If I can get away with 2"
I'll do that instead.

Mark Plancke
SOUNDTECH RECORDING STUDIOS
http://SOUNDTECHRECORDING.COM
Windsor, Ontario Canada
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:43 am

From: Temper3@x??x.xxx
Date: Mon Nov 1, 1999 3:58 pm
Subject: Re: sound stage was Re: Digest Number 9

i have heard so much about this 703...where can i get it...what sizes does it
come in....any info would be appreciated....thanks tim
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:44 am

From: Dan Nelson <dprimary@x??????xxxxx.xxxx
Date: Mon Nov 1, 1999 5:08 pm
Subject: Re: sound stage was Re: Digest Number 9

For a soundstage 2" would work since you don't have much bass in the room
you just want keep it from sounding like a cave on the video. if the
soundstage has concrete wall 4" may be required . 2" 703 does very well
down to about 250 hz and remember drywall absorbs low frequencies. For
your room if you have some bass problems you may need 4"
Have your calculated the rt 60 of your room? I will post Stephen
Marinick's filemaker sabin calculator soon. and Scott Foster's excel
speadsheets are in the file download area of the site now.
You may need some 2" and some 4"

here are some absorption coefficients

drywall 1/2 .29 @ 125 hz .10 @ 250 hz
2" 703 .17 @ 125 hz .86 @ 250 hz
4" 703 .84 @ 125 hz 1.24 @ 250 hz

Dan Nelson
www.studiotips.com
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:50 am

From: "CactusFire (A.S.)" <cactusfire@x??????xxxxx.xxxx
Date: Mon Nov 1, 1999 6:54 pm
Subject: Re: sound stage was Re: Digest Number 9

I also think that you will find that 2" 703 furred out from the wall by 2"
will behave almost exactly like 4" surface-mounted 703.

Andy
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:50 am

From: Dan Nelson <dprimary@x??????xxxxx.xxxx
Date: Mon Nov 1, 1999 5:56 pm
Subject: Re: sound stage was Re: Digest Number 9

Look up insulation supply companies in your phone book it comes in 1" to 4"
thick 2' by 4' sheets
2" seems to be the most common. The materials page on the site list other names
for it if you have problems finding it in your area.

Mark can you let me know if the 540 is metric panel sizes. I think 540 must mean
54 kg per cubic meter which is close to 3lbs per cubic foot for 703

Dan Nelson
www.studiotips.com
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:52 am

From: Mark Plancke <soundtch@x??x.xxxx
Date: Mon Nov 1, 1999 6:03 pm
Subject: Re: sound stage was Re: Digest Number 9

At 10:56 AM 11/1/99 -0700, you wrote:
>From: Dan Nelson <dprimary@e...>
>
>Look up insulation supply companies in your phone book it comes in 1" to 4"
>thick 2' by 4' sheets
>2" seems to be the most common. The materials page on the site list other
>names
>for it if you have problems finding it in your area.
>
>Mark can you let me know if the 540 is metric panel sizes. I think 540 must
>mean
>54 kg per cubic meter which is close to 3lbs per cubic foot for 703
>

Actually it's still measured in lbs per foot, hence the AF530 name.

30 is for 3.0lbs per foot.

And it's available in 2'x4' panels, just like 703.

Mark Plancke
SOUNDTECH RECORDING STUDIOS
http://SOUNDTECHRECORDING.COM
Windsor, Ontario Canada
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:54 am

From: SRF7@x??x.xxx
Date: Mon Nov 1, 1999 9:22 pm
Subject: Re: Digest Number 10

In a message dated 11/1/99 8:45:25 AM Eastern Standard Time, smitty@u...
writes:

> Does the type of fabric on the acoustic panels make any difference,

Yes.. Pretty fabric looks better than ugly fabric, and some stuff will burn
easier (burlap is cheap, takes dye easily, and can be made fire resistant).
You can use just about anything with an open weave (a taut linen upholstery
would reflect high end somewhat... no point in that).

> and is there a way to
> estimate how many panels I will need for a given space, or is it just
trial
> and error?

Trial and error is actually a pretty damned good way to go about it, but you
can try to calculate the Sabin number (reflectiveness as to sound) of the
surfaces of the room and an estimate of the amount and type of absorptive
material required to reach a target reverb time for the room so that you have
a starting point to jump to (which will probably save time and money in the
long run). I sent Dan a pair of spreadsheets I have used in the past but
they need to be tweaked for you room, and its just an estimate.

Personally I'll respect you more if you just go to the hardware store, lick
your thumb, close one eye, wave your thumb at your estimate of the materials
required, bring it all back to the studio and hit the target reverb time dead
center (or close enough to be satisfied) on the first try out of dumb luck...
but its your time, and your money, so you chose.

If you go the Wild Ass Guess (WAG) approach then I'd suggest sticking a 2'
wide cloth covered section of 703 across the diagonal of each room corner,
and then making some 4' wide by 8' tall (32 SF) 703 filled wood frames (3" to
6" thick) cover the front side with fabric and hang one every 12' (on
centers) or so around the walls with some air space behind between each frame
and the wall (a couple of inches will do, but more is better). Treat the
ceiling with something (install a drop ceiling with standard acoustic tiles,
or just glue them to the existing ceiling, don't waste your money on foam
unless you like the way it looks). Double pad and carpet the floor (if you
already have carpet just pull it up, double the pad up and reinstall the
carpet). If you do all that you are probably in pretty good shape for maybe
3 to 4 dollars per square foot. Pretty good bang for the buck.

If the room is too dead when you are done, take a couple of frames off the
wall, cover the back with cloth, mount casters, roll them in the corner, call
them gobos, and tell everyone you meant to do it that way in the first place.
If its still too live, make some more 703 filled frames and hang them as
clouds from the ceiling (sky blue would be a nice color for the fabric on
these). My $0.02

> And should panels be suspended from the ceiling? I have seen photos of
> panels hanging
> vertically in large spaces and I wondered if either horizontal or
vertically
> suspended
> overhead panels would be effective.

Yeah they call them "clouds"... sometimes they are absorptive, and sometimes
reflective, sometimes a little of both. In your circumstance you probably
don't want to lose space or site lines to centrally located vertical hanging
structures, so mount them parallel to the nearest surface (wall or ceiling)
with a bit of air gap behind.

None of this does anything for diffusion, but that is a whole nother bucket
of eels

>
> If there are basic resource books for this sort of thing, I'd appreciate
any
> recommendations.
>

Everest's Master Handbook listed at Dan's site would probably suffice, but
check out Malcolm's site as well (Dan has a link).

Good Luck

Scott R. Foster
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:54 am

From: SRF7@x??x.xxx
Date: Mon Nov 1, 1999 9:33 pm
Subject: Re: sound stage was Re: Digest Number 9

>Is 2" enough? I thought you had to go 4" 703 to get broadband absorbtion?

I think you do UNLESS... you leave an air space behind it.... Everest's
Handbook has an example (don't remember the change offhand, but air space
makes a big difference). Look what 1.5" fiberglass acoustic tiles (pretty
much the same stuff but with a big air gap behind) do compared to 1" through
6" 703 mounted direct to the wall.

MATERIAL SABINS/Sq FOOT AT (Hz) 125 250 500 1k 2k 4k
Avg.

FIBERGLAS 703 BOARD, 1 IN ON WALL 3 22 69 91 96 99 0.63
FIBERGLAS 703 BOARD, 2 IN ON WALL 22 82 121 110 102 105 0.90
FIBERGLAS 703 BOARD, 3 IN ON WALL 53 119 121 108 101 104 1.01
FIBERGLAS 703 BOARD, 4 IN ON WALL 84 124 124 108 100 97 1.06
FIBERGLAS 703 BOARD, 6 IN ON WALL 119 121 113 105 104 104 1.11
FIBERGLAS GRID CEILING, 1-1/2 INCH 97 100 86 101 104 106 0.99

Scott R. Foster
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:55 am

From: SRF7@x??x.xxx
Date: Mon Nov 1, 1999 9:37 pm
Subject: Re: sound stage was Re: Digest Number 9

In a message dated 11/1/99 10:58:41 AM Eastern Standard Time, Temper3@a...
writes:

> i have heard so much about this 703...where can i get it...

Any building supply warehouse, its just an open weave fiberglass insulation
board (more air than glass), Certainteed and others make equivalent products).

> what sizes does it come in....

lots... 1" to 6" thick, usually seen in 24" wide boards
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:55 am

From: SRF7@x??x.xxx
Date: Mon Nov 1, 1999 9:48 pm
Subject: Re: sound stage was Re: Digest Number 9

In a message dated 11/1/99 12:09:15 PM Eastern Standard Time,
dprimary@e... writes:

> here are some absorption coefficients
>
> drywall 1/2 .29 @ 125 hz .10 @ 250 hz
> 2" 703 .17 @ 125 hz .86 @ 250 hz
> 4" 703 .84 @ 125 hz 1.24 @ 250 hz

True but 2" 703 on 2x4 furring strips does about the same as 4" flat to the
wall for less $. You can set the furr strips 4" O. C. and run the panels
horizontal so lumber costs are minimal. Also running a 24" wide panel across
the diagonal of the room corners (vertically) will reduce low end out of all
proportion to the amount of material required (low end modes love corners,
and the air space behind is deep and variable which will eat low end on a
broad bandwidth). If you can spare the cost in room dimension, calculate
what you need using the above guide, cut the thickness in half and furr it
out 4"s. Works even better if you aren't doing the whole wall to build
light wood frames and hang them 6 or 8"s off the wall (ceiling), then the
sound impinges on both front and back of the panel and you can get Sabin
numbers greater than 1.00 out of thinner stock.

My $.02

Scott R. Foster

Scott Foster
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:56 am

From: Dan Nelson <dprimary@x??????xxxxx.xxxx
Date: Tue Nov 2, 1999 12:54 am
Subject: Re: sound stage was Re: Digest Number 9

I think the ceiling grid must have batts of fiberglass on top or something
because

MATERIAL SABINS/Sq FOOT AT (Hz) 125 250 500 1k 2k
4k

FIBERGLAS 703 BOARD, 2 IN E405 mount .40 .73 1.14 1.13 1.06
1.10
E405 mounting is 405 mm airspace or 16"

Everest's Handbook has a graph and the airspace does help the low frequency
absorption but not enough for 2" 703 w/ a 2" airspace to equal 4" 703 In his
graph it looks like 1" of 703 w/ 3" of airspace is more equal to 1.5 "to of 703

Does anyone have absorption coefficients for D 40 mounting - 1.5" airspace on
wood furring?
Where did you find the coefficients for 6" 703 I been trying to find them ?
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:59 am

From: SRF7@x??x.xxx
Date: Tue Nov 2, 1999 5:36 pm
Subject: Re: sound stage was Re: Digest Number 9

In a message dated 11/1/99 7:55:08 PM Eastern Standard Time,
dprimary@e... writes:

> Does anyone have absorption coefficients for D 40 mounting - 1.5" airspace
on
> wood furring?
> Where did you find the coefficients for 6" 703 I been trying to find them ?
>
>

I think I got those from Malcolm, though as I recall they were estimated not
measured.

Scott R. Foster
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am

Postby archive » Sun Apr 11, 2004 3:59 am

From: SRF7@x??x.xxx
Date: Tue Nov 2, 1999 5:56 pm
Subject: Re: sound stage was Re: Digest Number 9

In a message dated 11/1/99 7:55:08 PM Eastern Standard Time,
dprimary@e... writes:

> Everest's Handbook has a graph and the airspace does help the low frequency
> absorption but not enough for 2" 703 w/ a 2" airspace to equal 4" 703 In
his
> graph it looks like 1" of 703 w/ 3" of airspace is more equal to 1.5 "to
of
> 703

2x4 furring would yield a 3.5" air gap, so the yield should be a bit
higher... even better would be to hang the panels 6 to 8 inches off the wall,
with similar sized gaps between panels forming a pseudo cavity so that both
sides of the panel can work on absorption.

Scott R. Foster
archive
 
Posts: 4697
Joined: Sun Mar 21, 2004 6:26 am


Return to 1999 posts

Who is online

Users browsing this forum: No registered users and 1 guest