Natural Science Forum / Physics / Acoustics / April 2008

I am interested in purchasing a book covering active noise control.
My background is fairly strong in controls, and I have had several
vibration courses.  I am currently reading through "Fundamentals of
Acoustics" by Kinsler, Frey, Coppens, and Sanders.  There are several

Does anyone know the upper limit of a Helmholtz resonator? As high as
13 to 16 kHz perhaps?
Ron

Hello People
I have recently started using Cadna noise modelling package. I have
found it to be fairly user friendly, however, when I import AutoCad
DXF files, Cadna assumes the units of measurement in the DXF is metres

Is the absorption data on this web page for perforated wall panels
possible?  It calculates to 1.36 at 500Hz and 1.2 at 1000 Hz.  Are
there resonator effects with this type of perforated that can give
this type of performance?

I am working to design an enclosure for an engine and I was wondering
how big of a difference it would make if I used plywood lined with
acoustic foam vs. steel lined with acoustic foam. I've noticed that
all commercial options are steel, but I also know that plywood would

I am in the market for some acouistic modelling software. I would need
this to do barrier attenuatiin  calculations for barriers along the
edge of roads etc. Also for noise affecting housing developments etc.
I know of two systems. These are SoundPlan and Cadna. Does anybody