The software for Phoenix
organs has been developed using the Yourdon method. This is a modern
structured analysis and design technique that is widely used in both business
and computer control systems. Briefly, it involves the definition of the
system requirements and then expands these in to processor tasks. By
developing the control software using this formal method, the Phoenix Organ
software is much more likely to offer a reliable service than other systems.
A pipe organ usually contains
thousands of pipes. Each pipe can be voiced, regulated and tuned.
Our system works on a similar basis. We can voice, regulate, adjust
the attack and release, and tune every note of every rank independently. Our
voicing software is written in the latest PC development environment which
takes the strain out of setting up an organ.
On a pipe organ, moving
the expression pedal does not just vary the volume of the sound, it also
changes the tone by damping higher frequencies. The Phoenix software
simulates this by also attenuating these higher frequencies. The
calibration curves of our expression can be set using the voicing software.
The effect of wind
variation on a pipe organ can have a significant effect on the sounds we hear.
Our software simulates this effect, and using our voicing software, each
stop's loading on the bellows can be set across four areas of the keyboard.
A large Open Diapason's bottom octave will use far more wind than say the
top octave of a Larigot. Each stops response to bellows movement is
also adjustable. Wind calculations are performed hundreds of times per
second to guarantee pipe-like response.
A pipe organ tremulant
changes the pitch and loudness of a stop. We have incorporated this into
our design, plus a feature to provide some randomness in tremulant levels which
occurs in pipe reed stops.