Pipe organs can have hundreds, if not thousands of organ pipes, all with their own peculiar characteristics. Even the best pipe organs are not in absolutely perfect regulation and tuning, and it is these and other facets that give the organ it's intrinsic character. The Wyvern voicing programme allows control over an unparalleled number of parameters to emulate the idiosyncrasies of the pipe organ, or even the styles of any one builder. A broad overview of these controls are as follows:
Wyvern voicing software allows control over each note of every stop. Some systems simply apply volume adjustments to each note, but the Wyvern system goes so much further giving control over tone, tuning and over transient tones of attack and decay. We can even reach into single ranks of Mixtures, and (after muting the other ranks) regulate each rank in turn.
The stops can be configured in different ways, through the simple C/C# sides to other possible configurations; so that a stop moves naturally through a sequence of speakers, ensuring that the sound moves in the same manner as a traditional pipe organ. It is also possible to assign any speaking stop to a choice of up to four channels. This is especially useful when a stop requires more presence, such as a large reed.
In some pipe organs different departments are often some distance from each other. The resulting acoustical delay also adds a spacial effect to the organ. We can adjust the timings of the speech of each department in milliseconds to emulate the acoustical delay.
Most electronic organ builders treat the swell box as just a volume control but it is more complex than that. The effect of opening and closing the shutters varies from organ to organ, the most noticeable being that when the box closes the treble frequencies are dampened and bass frequencies become more prominent. The Wyvern system allows us to calibrate bass and treble response separately so that this same effect is achieved.
In every pipe organ there is a certain amount of variation in the wind supply through the demands of the pipe work. Even in organs with a rock-solid wind supply, there is a certain amount of fluctuation. Certain stops or portions of stops make greater demands on the wind supply, such as the bottom octave of the Open Diapason or Open Wood. These will obviously use much more wind than the top octave of a 2' stop. The voicer is able to set up the amount of wind taken from the chest for each stop, adjust the sensitivity to wind demand and also set the wind demand for each department separately. This rate of drop (or slump) and recovery can also be set.
In most pipeless organs the biggest give-away is the rather abrupt way the basses of the 32', 16, and 8' stops suddenly stop. If you listen to a pipe organ you will hear that the sound takes slightly longer to die away, even in the driest of acoustics. The attack and release can be adjusted on a note by note basis for each stop. The note by note feature is especially important at this point as each note will behave differently throughout the compass. We are not simply speeding up or slowing down how fast the actual stops sounds but are dictating how the pipe should speak, from the very first moment the air enters the pipe to the moment when it leaves.
It is easy to store a number of samples of different character within the organ. It may be that a certain type of Stopped Diapason does not agree with either the clients requirements or, perhaps the acoustics of a particular church. Accordingly we try to provide a choice of samples that can be changed in seconds, from a liquid-toned Hill Gedeckt to an articulate Rieger Holzgedeckt. This feature is particularly useful when trying to ensure a good blend of stops when matching the organ to the particular acoustics, thus ensuring an instrument that has a clear musical purpose and a stylistic unity that matches the particular building.
In the first paragraph of this article we mentioned the randomness of pipe organs, through tuning and speech. This is part of the charm of any pipe organ. The fact that the tuner may have started on the organ at 9.00 am and finished at 5.00 pm does not guarantee that the instrument is in perfect tune. Fluctuations in temperature and humidity affect the tuning - especially the reeds. The Randomisation feature allows us to inject as much or as little inconsistency into individual notes of individual ranks - for example we can make the reeds drift slightly more than the flues. In less sophisticated methods, when the stops are put out of tune to try and obtain a warmer sound, each stop goes out of tune en block, often causing an unpleasant and extremely unrealistic phasing effect. In reality each pipe behaves differently. We can set up this feature so that it affects either the whole compass of the stop, or alternatively, different portions of the compass to greater or lesser degrees.
Importantly, the nature of the randomisation is that the organ, like a pipe organ, is forever changing. The changes may well be slight, individually almost imperceptible, but like a pipe organ it is a "living" sound - producing an instrument with integrity and above all, character.
These are just a few of the many features available to us when regulating a Wyvern organ. There are many other features that allow us to configure and regulate an organ to exacting standards.