[Chris Hornbeck]

On 22 Jul 2008 00:06:37 GMT, Roy W. Rising
wrote:

I think this oversimplifies the pressure vs. velocity subject. I've just
reviewed Howard M. Tremaine's discussion of mics in his Audio Cyclopedia.
In *every* case he refers to ribbon-velocity mics as contrasted to pressure
responding condenser and dynamic types. However, he acknowledges there
certainly are bi-directional condenser mics ... without explanation.
Generally, directional patterns are accomplished by controlling the phase
of sound pressure reaching the back of the diaphragm. The Altec 639 summed
the outputs of forward facing dynamic and ribbon elements in one of the
very few attempts to use the 90 degree phase difference between pressure
and velocity.

I think it's important to keep front-'n-center in mind
that radiation pattern depends *only* on how the diaphragm
is exposed to room air. Different generating mechanisms
affect this not a bit.

Of course, you're not suggesting otherwise, but a casual
reading by a newcomer might be misinterpreted.

Bitch, bitch, bitch...



Much thanks, as always,
Chris Hornbeck