[Don Pearce[_2_]]

On Thu, 5 Feb 2009 06:19:57 -0800 (PST), wrote:

x-no-archive:

Jens Rodrigo wrote:
Ray Thomas wrote:
I'd seen pics of them before and wondered about their size and
construction....pretty hefty price on the DPA spheres of 57 UK
pounds ! I I imagine the Schoeps items are similar in price. I was
wondering
if toy balls (eg tennis balls or smoother items), or even rubber
squash balls with appropriate holes cut might function ok. I
wonder if they'd need to be hard ....like billiard/pool-table balls...
or whether a softer foam or plastic or rubber might work just fine,
as I imagine it's the reflective surface property which is decisive,
rather than mass per se ? Certainly leaves a lot of scope for
experimentation.


It's a good idea to build or find a small wooden ball.
The discussion about wood and its warm sound is interesting.
"Does wood really sound warm?" at rec.audio.pro
http://groups.google.com.au/group/re...24d9332d1370e5
The bigger the ball, the more the treble peak wanders to lower
frequencies.

Here is a Neumann pressure microphone with
spherical acoustic surface M50:
http://www.neumann.com/download.php?...d=lect0010.PDF
Look how the frequency response changes
with objects of different shapes.

Cheers Jens

http://www.neumann.com/download.php?...d=lect0010.PDF

was interesting...

this mic, that many consider to be an excellent mic, has +6dB boost
at 10 kHz

Mark


As long as you know that, it is not a problem. If you need a flat mic
response, just use a parametric equalizer to remove the 10kHz peak.

d