PMA AMPLIFIER SERIES
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COMPENSATION FILTERS
COMPENSATION FILTERS
One of the most inspired features of the PMA Amplifiers is the inclusion of no-nonsense DSP tools
that make easy the adjustment of the audio signal to neutralize the effect of listening room condi-
tions that directly impact the acoustic response of the speaker systems.
For clarity, these features address those aspects of the listening room materials and loudspeaker
positions which alter the
direct sound
of the PRO loudspeaker system.
These features do not in
any way fall within the category of so-called “room correction” or “room tuning” paradigms,
which, in our opinion, are not only mis-named, but are also misguided in their objectives*.
The PMA Compensation filters compensate for the acoustic response changes resulting from screen
and listening room fabrics that come
between the loudspeaker and the listeners ears
and therefore
alter the direct response (direct path from speaker to listener, free from any reflections) of the
loudspeaker. There are also filters to neutralize the effect of placing a speaker very close to the
room corners as doing so causes the “space” into which the speaker radiates to be bisected thereby
directing more of the low frequency information into what we would call the “direct sound”.** The
included filters compensate for such “loading” by removing the energy that would normally not be
forced by the room surfaces into the direct response.
These specialized filters have been designed by Pro Audio Technology using a thoughtful combi-
nation of laboratory measurements and sophisticated computer models to accurately equalize for
each of the conditions below. You, the installer are not required to have knowledge of engineering
or acoustics, just a knowledge of the listening room materials and loudspeaker locations.
Also included are high and low pass filters to facilitate the combination of subwoofers with satellite
full-range speakers in music and distributed audio applications.
SCREEN COMPENSATION
The screen compensation filters within PMA Manager neutralize the high-frequency roll-off created
by perforated or woven video screens.
You do not need to know the acoustic respsonse of your screen’s material - we’ve taken care of that
for you. All filters were developed by measuring, in a laboratory, the actual acoustic response of
the most popular screen brands.
* For more information about so-called “room tuning” or “room correction” and the perils thereof, take the PRO Training Program as the subject is
addressed in painful detail!
** When the speaker is placed very near a neighboring room wall, the low frequencies, whose wavelengths are very long (5’-50’), are forced into
the room toward the listener without what we would normally define as a “reflection” occurring. The energy does indeed “bounce” off the neigh-
boring wall, but it does so so early in time and with such neglible attenutation that when the “bounce” arrives at the listeners ears, it is for all practi-
cal purposes at the same level and in-phase with the sound radiated directly from the speaker to the listeners ears. Our ears integrate this energy
into one sound. Furthermore, this happens uniformly throughout the listening area, which is not true for reflected sound that is delayed in time
sufficiently as to create sufficient enough attentionation and phase shift to create an “interference pattern”. The condition we are addressing is the
low frquency gain created by the bisection of the acoustic space at low frequencies.
