The sound generation
process in a Phoenix Organ uses the sample replay technique. The starting point
is with a digital recording of a rank of real organ pipes. A selection is made
of these, covering five octaves, for programming into our sound
card.
One of the key
issues in the control of an electronic organ is the allocation of sound
resources. In a Phoenix Organ, a separate, independent generating source is
used for each note of each stop that is played. A Phoenix sound card has 64
generators, but we lose 8 of these in order to do expression if the department
is enclosed, so each of the remaining 56 can replay one sample at a time. If
seven stops are assigned to a single sound card, this will allow up to eight
notes to be played with all stops drawn simultaneously. However, the number of
stops (or mixture ranks) on a sound card is normally limited to five, and we
would also try to put stops which would not be used together on the same card -
like a Cornopean and a Celeste. Not only does this increase the polyphony of
the instrument, it also yields much better quality.
Some stops can
utilise up to forty or fifty long samples - virtually one per note, which is
particularly important for flutes which contain complex and uneven starting
transients (chiff). This ensures that these transients are naturally re-created
from the original pipe itself. The use of multiple samples also avoids the
"chromatic whistling" effect which seriously flaws the sound when too few
samples are stretched over too big a key range. These big stops use up memory
at an alarming rate, but advances in memory size have meant that it is now
possible to fit about five or six of these stops on a sound card, and within a
few months memory size will not be a problem, as we already have prototypes of
a sound card that has 64 Megabytes of memory. This is equivalent to 13 minutes
(780 seconds) of CD quality samples, which will make a five second sample for
every note of every stop a reality.
Stop lists can, at
times, be pretty meaningless, and we have all experienced the disappointment
when the sound emanating from the organ does not match one's expectations from
the engraving on the drawknob. This applies as much to pipe organs as
electronic ones. For this reason, the voicing software has tremendous control
over the sound and timbre of each individual note for each stop, and easily
gives us the means to turn a Lieblich Gedeckt into a Stopped Diapason, or even
an Echo Gamba into a leathered No 1 Open (yes really!) it is better to start
with the correct sample in the first place. Thus we have the added flexibility
of being able to easily and quickly change samples on site, so that the
organist can get exactly the sound that they had envisaged, and modern
technology interferes minimally with the pipes natural sound.
When your Phoenix
Organ is installed, our skilled staff will carry out fine regulation and
voicing so that the instrument meets your expectations. Voicing is carried out
using our sophisticated voicing software which gives unrivalled control over
the final sound.