Tony wrote:
Thanks! This is a very easy to use implementation.

:-) Useability always takes more effort to implement than the actual
calculations, but I think the effort is worth it!

How much detail does Cox and Antonio's book go into about this calculation?
Does it take into account resonant modes which involve more than one hole or
slot? I can see I will have to buy this book but it would be nice to know
that while I am saving up.

They go into lots of detail. The chapters are generally structured such
that they discuss a practical situation, then go through the maths, then
go through a practical implementation using the maths they've just
described. They try to give every equation a practical application,
this is why I like the book so much.

Also, the calculation depends on knowing the flow resistance of the damping
material. Is there any handy place where one can look up the approximate
flow resistance of commonly used mineral fibre materials?

There are a few (small) tables in the book, but what is more useful is
that there is a whole chapter (chapter 5) on porous absorbers, and a
whole section (5.3.1) on the various methods of calculating flow
resistivity.

Finally a word of warning. The panel thickness can be set as low as 1 mm.
In most configurations panels only a few mm thick would be far from rigid
and, depending on the intended frequency of operation, that could have a
very major effect on the performance.

This is true, therefore I have placed a caveat in the instructions that
warn about the difference between theoretical predictions and actual
performance. If I have not made this point clearly enough, then I will
reiterate it.

Chris W

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