I was wondering about windows and how they affect the sound in a
studio.

I know they absorb some sound but how much of the sound passes through?


At what frequency do the waves get reflected, which ones pass through?
I suspect the highs mostly get reflected and then at some point around
500hz perhaps they start to just bypass the window all together.

How do curtains effect this? Do you simply add their absorption
coefficient to that of the windows to see what is absorbed and the rest
either passes through or is reflected.
Has there been any studies of this?

Lex,

At what frequency do the waves get reflected, which ones pass through? I
suspect the highs mostly get reflected and then at some point around 500hz
perhaps they start to just bypass the window all together.

This exact subject is now being discussed - fervently! - in a popular audio
forum. So far nobody has shown hard data that extends down to the lowest
frequencies. I'm sure the "crossover" frequency is well below 500 Hz.
Probably more like 60 Hz or lower, depending of course on the thickness of
the glass. It's a huge pain to actually measure this, but I hope to attempt
it one of these days using a large glass door, my Carver Sunfire subwoofer,
and the ETF analysis software.

How do curtains effect this?

Curtains absorb only at higher frequencies, so they will avoid those
reflections off the glass.

Has there been any studies of this?

Yes, but none of the data I've been able to find (via Google) goes to a low
enough frequency.

--Ethan

Can you show me where it's at? I would be interested in reading what
people are saying about it. Thanks.

"Ethan Winer" ethanw at ethanwiner dot com wrote in message
...
I'm sure the "crossover" frequency is well below 500 Hz.
Probably more like 60 Hz or lower, depending of course on the thickness of
the glass. It's a huge pain to actually measure this, but I hope to
attempt
it one of these days using a large glass door, my Carver Sunfire
subwoofer,
and the ETF analysis software.


Does this mean you suspect that frequencies below 60 Hz start to pass
through, and everything above it gets reflected back into the room...or
what?

I've always been under the impression that windows let just about everything
below 300 Hz pass through. Ignorance was bliss...

In article .com,
"lex" wrote:

I was wondering about windows and how they affect the sound in a
studio.


Everyone knows that Linux sounds better than Windows. Duh.

-Todd
(just in case anyone thought that discussion was done)

Tommi,

Does this mean you suspect that frequencies below 60 Hz start to pass
through, and everything above it gets reflected back into the room...or
what?

Yes, but it probably occurs lower than 60 Hz, and of course it depends on
the thickness of the glass.

--Ethan

Lex,

Can you show me where it's at?

It's over at the Sound On Sound forum:

www.soundonsound.com/forum

Look in the Studio Design & Acoustics section for "Windows behind monitors."
You'll have to wade through a fair amount of name calling by a few
trouble-makers, but there's also some solid information if you read through
the whole thread.

--Ethan

Lex,

lex wrote:
Can you show me where it's at? I would be interested in reading what
people are saying about it. Thanks.


The concept of a crossover frequency in the context as used by Ethan
physically does not exists.
This is explained to Ethan in the referred thread. Not that that should
make any difference.

So Ethan diverts the related topic in that thread to absorption in the
room.

Even with standard low TL single leaf building materials (including
window panes) the amount of acoustic energy heard outside (however loud
it seems) is practicably negligible.
A TL as low as 20 dB roughly means that the acoustic energy outside is
still only 1 %.

One clearly should distinguish between discipation of energy inside
panels (= absorption) and what passes through.
The 60 Hz Ethan talks about must be defined by his darts game.
TL is a gradual thing defined by lots of things (mass-law, coincidence,
panel modes, stiffness, whatever). The concept cross-over frequency in
this specific context is an invention of Ethan.

Some calculations and explanation (look a bit further down in the
post):
http://www.recording.org/ftopicp-177905-.html#177905

Kind regards
Eric

PS:
Trouble makers for Ethan are those that don't support his believes and
Guru status.

You can also look here

Windows - some loose thoughts
http://tinyurl.com/4zyu4
This topic related directly (entered during..) to the thread Ethan
referred to:

window behind monitors.... best way to treat this??
http://tinyurl.com/5jnaw

Kind regards
Eric