Pressure Zone Microphone
(330-1080A)                Features                   Faxback Doc. # 32714

The Pressure Zone Microphone (PZM) is a dramatic new breakthrough in
microphone technology.  It will completely reshape your ideas about what a
microphone can and cannot do.  Anything the human ear can hear may be
accurately picked up and reproduced by the PZM.

The special design of the PZM allows you much more freedom in the placement
of a microphone and eliminates the familiar "hollow" sound associated with
recordings where the sound source was "off-mic."

The complete hemisphere pick-up pattern of the PZM eliminates the need for
concern over the angle between the sound source and the axis of the
microphone.  As long as the sound source is within the hemispherical pick
up pattern of the PZM, it will sound "on-mic." The distance between the PZM
and the sound source has no effect on the quality of the sound
reproduction.

You may change the pick-up pattern of the PZM, using acoustically absorbent
material, when more directionality is needed.

Pressure Zone Microphone and PZM are registered trademarks of CROWN
International.

PZM:  HOW AND WHY

If you are not the curious or technical type, you may skip this section and
proceed to "Preparation for Use" and "Applications."  However, the PZM is
so different, we think you'll want to know more.

Conventional microphones have always been hindered by interference between
sound coming directly from the source and sound reflected from the primary
boundary (the wall, floor, or ceiling closest to the microphone).  This
interference happens because the direct and reflected sounds reach the
microphone at slightly different times.  This results in reinforcement of
some frequencies, canceling of others, and an overall unnatural
reproduction of the sound.

The PZM design eliminates this interference and actually uses a combination
of the direct and reflected sound waves to achieve its amazing sound
reproduction.  the PZM contains an electret microphone capsule permanently
mounted a short distance from is attached primary boundary plate.

When the sound waves strike this plate, a "pressure zone" is created in the
space between the electret element and the boundary.  In the pressure zone
the direct and reflected sound waves are coherently in phase and reinforce
each other.

The electret capsule detects the changes in pressure in the pressure zone,
rather than the moving sound waves, and therefore is unaffected by the
distance of the sound source from the microphone or the angle of the source
to the microphone (as long as the source is within the hemisphere pattern
above the primary boundary plate).

NOTE:  For best frequency response, especially bass response, the PZM
       should be mounted on a hard, flat surface at least four feet square.


(YO/EB 4/29/96)