Swellbox and crescendo wheel
Swellboxes are enclosures with vertical venetian blind-type shutters controlled by the swell pedals (or ‘swell shoes’). As a given shutter closes, the pipes contained in that swellbox will sound quieter and darker (with lesser amounts of high overtones). The Mátyás Organ’s swellbox characteristics, through careful measurement and modeling, are brought to life with breathtaking realism. The swellbox can be operated by using the Sweller pedal (left pedal on the figure). Its operating direction can be set on the Center and Left pages.
The crescendo wheel is an axially rotating drum operated by foot control, and is used in place of a conventional crescendo pedal. The wheel is positioned to the left of the foot-operated swellbox pedals. Sliding (rolling) it forward from position 0 to a higher position triggers stops in a preset user-defined manner, according to the sequence contained in the respective Crescendo Program. There are 3 independent crescendo programs available just as in the real organ.
There are two small LEDs near the 2-segment LED display. These are highlighted according to the last movement of the crescendo wheel and they can be canceled with the general cancel button.