Flexible Voicing

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 new Wyvern WpX 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:

Note by Note Regulation

Unlike software driven systems the WpX voicing software allows control over each and every note of every stop. We can even reach into single ranks of Mixtures, and (after muting the other ranks) regulate each rank in turn. Unlike inferior sampled systems this does not simply apply to volume of each note, but also the tone and tuning, attack and decay.

Wind Chest Layout

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.

Departmental Delays

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.

Expression Pedal Calibration

Most electronic organ builders treat the swell box as simply a volume control. This is not the case. The effect of opening and closing of the swell box varies from pipe organ to pipe organ. The most noticeable thing is, that when the box closes the treble frequencies are damped, and the bass frequencies become more prominent. The Wyvern WpX system allows us to calibrate bass and treble response separately. the expression pedal so that the same effect is achieved i.e. rate of crescendo.

Bellows and Wind Demand

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 Large Open Diapason, or Open Wood. These will 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. The rate of drop (or slump) and recovery can also be set.

Attack & Release

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 portions of the compass. We are not simply speeding up or slowing down how fast the actual stops sounds. We 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 am and finished at 5 pm does note guarantee that the instrument is in perfect tune. In fact, fluctuations in temperature and humidity affect the instrument and it will still not probably be perfectly in tune. The Randomisation feature allows us to inject as much or as little inconsistency into the various features mentioned above. This has proved useful in the tuning feature. With lessor electronic organs the tuning control is restricted to whole stops. 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.