Hammond Model A, Manual, Page: 58 / 298

It
is also the most important single factor to be considered in planning an organ
installation as proper reverberation makes
it
easier to attain all
of
the other
requirements necessary for a perfect installation.
In
a Hammond organ installation, the proper amount
of
reverberation may be secured
in three ways:
1. By
the
successive reflections
of
the sound by the boundaries of the auditorium.
2. By the Hammond Reverberation Control.
3.
By placing the tone cabinets in a chamber,
the
boundaries of which cause the
organ tones to reverberate before reaching the auditorium.
REVERBERATION IN THE AUDIITORIUM
The reverberation that results from the
successive reflections
of
sound back and
forth by the boundaries
of
the auditorium itself is most desirable from the
installation engineer's point of view. (By auditorium we mean any audience room such
as a church or concert hall.)
In a reverberant auditorium less power is necessary and problems
of
sound
distribution are greatly simplified and, therefore,
the
best possible musical
results are usually obtained as a matter of course. Unfortunately, however, the
reverberation characteristics
of
an auditorium usually are not alterable by the
installation engineer, and he must accept them, good or bad as the case may be.
A reverberation time of one second when a two-thirds capacity audience is present is
usually sufficient
if
reasonable care is taken in locating the organ equipment for
proper distribution and balance although a slightly longer reverberation time is
often desirable. It
must be remembered that the reverberation time in any enclosure
is greatly reduced when an audience is present. In general, the higher the ceiling
of the auditorium, the less effect the presence of an audience has on the
reverberation time; however, this effect is always considerable.
If
the natural
reverberation in the auditorium is insufficient for best musical results from the
organ, another method must be used to properly reverberate the organ tones.
HAMMOND REVERBERATION CONTROL
The Hammond Reverberation Unit provides an effective means
of
securing proper
reverberation in all types of installations where the natural reverberation in the
auditorium is insufficient. Experience has shown that best installations in homes,
radio studios, mortuaries, and small churches include a tone cabinet equipped with
reverberation control.
It
may also be used to improve the effectiveness of the organ
in auditoriums where considerable natural reverberation is present, but where this
natural reverberation is characterized by an objectionable echo occurring after the
organ tones have seemingly ceased. The Hammond Reverberation Unit will not eliminate
an echo or reduce the natural reverberation time, but will often make this natural
reverberation more pleasing to the ear by filling in that period between the time
the organ tones seem to cease and the echo occurs. The Hammond Reverberation Unit
will not add to the reverberation time in auditoriums already having excessive
natural reverberation. As the reverberation unit is connected to the electrical
system
of
the organ and provides reverberation at the source of sound rather than
after
the
sound comes from the speakers, it allows the installation engineer to
place the tone cabinets for best results in balance and distribution without the
necessity of compromise for reverberation considerations.
3