Hi all, another question in the sam vein as those i have been asking. I
am working with a very difficult hall, its a strange shape (like the
profile of a diamond 2 long 90* side walls and 3 walls along the back
linking them up.) Its all concrete inside with no soundproofing. This
makes the whole place very prone to echos and also gives very low gain
before feedback for the musicians with lots of open mics. Is there any
portable soundproofing solution? or else somewhere i can get sound
panels per unit from? (the hall is in mauritius so everything has to be
flown or shipped in!) any soundproofing ideas?

M

Sound proofing will not help the echos, it will help keep sounds in or
keep sounds out. Acoustic treatment will help the echo

theclyde wrote:
Sound proofing will not help the echos, it will help keep sounds in or
keep sounds out. Acoustic treatment will help the echo

ok, what is the distinction between acoustic treatment and
soundproofing? Any suggestions then?

M

Soundproofing prevents sound from passing. A room with 2' thick
concreate walls and ceiling and no doors is probably soundproof. No
sound would get in from outside the room. And a drum kit inside the
room would not be heard from outside. Hmm.. can we put drummers in a a
room and seal the door with concrete? Sort of like Waterproof. Water
cannot get in or out.

Acoustic treatment makes the room sound better. Takes away echo, takes
away standing waves causing extra bass. Takes away super easy feedback,
deadens a room, livens a room, adds bounce or feel to a room. Makes it
a more suitable place to record.

I am not an acoustic treatment expert. But you will have much better
luck finding an answer if you have the right question.

BTW - Stay away from egg cartons

wrote:
Hi all, another question in the sam vein as those i have been asking. I
am working with a very difficult hall, its a strange shape (like the
profile of a diamond 2 long 90* side walls and 3 walls along the back
linking them up.) Its all concrete inside with no soundproofing. This
makes the whole place very prone to echos and also gives very low gain
before feedback for the musicians with lots of open mics. Is there any
portable soundproofing solution? or else somewhere i can get sound
panels per unit from? (the hall is in mauritius so everything has to be
flown or shipped in!) any soundproofing ideas?

Ok, it sounds like your fundamental problem is that the hall's
reverberation time is way too high.

If you're not familiar with this value, it is defined as the time it
takes for a reverberant sound field to die away by a predefined number
of decibels.

You can measure this value in a reasonably scientific way by doing the
following:

o Get a CD of test signals - one with white noise on it.
o Set up a speaker in the centre of the hall and play the white noise
really loud.
o When the sound field in the hall has stabilised i.e. it has become
as reverberant as its going to get, cut the sound and simultaneously
start the stopwatch.
o Stop the stopwatch when all echoes have died away and become
inaudible.

The value (in seconds) that you get will be reasonable estimate of the
rooms reverberation time or RT60 (the 60 refers to the fact that you
have timed a 60dB drop in the level of the sound field)

Acceptable RT60 values are proportional to the volume of the hall. If
my memory serves me correctly, for a hall of about 2000 cubic metres,
the acceptable RT60 values are in the range 1.4 to 1.6 seconds for music
and about 20% shorter for speech.

I don't have a copy of F. Alton Everest's "Master Handbook of Acoustics"
to hand, but in that book there is a graph showing acceptable RT60 times
against room volume for both speech and music.

In your case, for sound treatment to have any effect, it will need to
reach from floor to ceiling (how high is the hall?). The best
suggestion I can offer is to hang really heavy theatre drapes around as
much of the wall area as possible. If the drapes can be spaced away
from the wall by about 1/2m, so much the better.

Also, if you can hang multiple short lengths of theatre drape from the
ceiling at 90deg to each other, this will help break up the flat surface
area of the ceiling, and disrupt front-to-back and side-to-side echoes.

Drapes will help for the frequencies used in speech, but will not help
too much if a rock band wants the bass pumped up. Bass will pass quite
easily through the drapes (bass resonance is always the biggest problem
in sound treatment).

Maybe you should present the idea of acoustic treatment to the owners of
the hall to see if they could install something permanent. If the hall
is often used for concerts or recitals, then it would be in the owners
interest to have such treatment installed.

Chris W

--
The voice of ignorance speaks loud and long,
But the words of the wise are quiet and few.
---

Its all concrete inside with no soundproofing.

As others explained, sound proofing relates to keeping noise in or out of a
room, and acoustic treatment makes the sound inside the room better. Even
though both fall under the umbrella of "acoustics," they are completely
different.

Is there any portable soundproofing solution? or else somewhere i can get
sound panels per unit from?

If you're on a tight budget you can make absorbing panels from rigid
fiberglass. If you'd rather purchase commercial panels that are portable and
also Class A fire rated, I hope you'll forgive this link to my own company:

www.realtraps.com

--Ethan

Ethan Winer wrote:

If you're on a tight budget you can make absorbing panels from rigid
fiberglass. If you'd rather purchase commercial panels that are portable and
also Class A fire rated, I hope you'll forgive this link to my own company:


Thats an interesting site. Im intrigued tho, My dad has a company that
works with fibreglass. How would i go about making soundproofing panels
out of Fibreglass? It would help a lot in our setup as we could test
and adjust, rather than ordering panels in from abroad...