Klarinet Archive - Posting 000468.txt from 1995/06

From: "Edwin V. Lacy" <el2@-----.EDU>
Subj: Re: Down In The Dumps
Date: Wed, 21 Jun 1995 02:09:35 -0400

On Wed, 21 Jun 1995, John Baetens wrote:

> On Jun 20, 2:27pm, Fred Cicetti wrote:
>
> > Here's my question. Is there anything I can do to improve
> >the acoustics in the cellar? It's all poured concrete with a
> >wood ceiling....
>
> Doug Cook suggests (among other things):
>
> >...If you can do something to make the walls less parallel,
> >that can help. The resonances die out quickly if
> >they're essentially bouncing in random directions.
>
> While you are making your concrete walls less parallel,
> let's see if you can leap tall buildings in a single bound.

Actually, there is a fairly simple way to alter parallel surfaces to make
them disperse sound waves rather than reflecting them.

This is going to be a very imperfect representation because of the
limitations of the system, or my limitations in using it, but here goes:

/////////////////////

The straight line represents the original wall, and the angled lines
represent panels which you attach to it. The angle doesn't have to be as
acute as shown here. Just attach furring strips of different thicknesses
to the wall with masonry nails and connect them with panels.

Even more effective is to use varying sizes of panels and varying
angles. Also, the degree of hardness or softness of the material of the
panelling can make a big difference, as can putting an insulating
material such as styrofoam behind the panels.

Well, this could easily get into a very extended discussion of room
acoustics, coefficients of absorbtion, reverberation times, etc. My
experience has been that acoustics is pretty much a matter of guess work,
anyway. Even supposed experts have been known to make some famous and
costly mistakes, as for example, in the original Philharmonic Hall in
Lincoln Center. Let's just say it is an inexact science, or that there
is a degree of intuition involved in it.

Ed Lacy
el2@-----.edu

   
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