Earthworks PM40T User Manual - page 5
The PianoMic™ System provides the following benefits:
• Excellent overall piano sound with uniform level from all strings
• Superb sound with the piano lid up or down
• Tremendous gain before feedback
• Minimal leakage from other instruments surrounding the piano
(with piano lid closed)
• Microphones are not visible from outside the piano
People are astonished when they hear the exceptional sound quality of
the PianoMic™ System with the piano lid closed. Conventional microphones
perform poorly in a piano as the sound inside the piano is coming from every
direction and from multiple sound sources. Every string is a sound source. The
soundboard is a large and complex sound source. In addition, sounds are re-
flected off the piano sides, the soundboard and the piano lid multiple times with
little attenuation. Sounds inside a piano are randomly arriving from every pos-
sible direction at similar levels, all at the same time. This is a classic example of
a “diffuse sound field” which is defined as a confined area where there are multiple
sound sources and multiple reflections arriving at the microphone from every an-
gle at similar levels simultaneously. A microphone that is placed in such a diffuse
sound field has to pickup all of the sound with a proper tonal balance. For optimum
results, this task requires a High Definition Random-Incidence Microphone.
Conventional microphones
are “Free Field” micro-
phones, and regardless
of their pickup pattern are
designed to only pick up
sounds accurately in front
of the microphone (See
Figure 2).
Random-incidence micro-
phones are designed to
uniformly pick up sounds
arriving simultaneously
from all angles and direc-
tions, rather than to the
sound coming only from
a primary source that is in
front of the microphone.
Random-incidence micro-
phones have exceptional ac-
curacy and tonal balance in
a diffuse sound field, where
sound arrives from all direc-
tions randomly and simulta-
neously (See Figure 3).
4
Figure 3. Random Incidence Microphones inside a piano pick
up sound accurately from all directions
Figure 2. Conventional “Free Field” Microphones inside a piano
only pick up sound accurately in front of the microphone