You can use electronic devices or modules that connect via MIDI expander ports. The will also need to connect a power supply to the device. It also needs to be within reach of the inputs of your audio amplifier.

There are two basic types of sounds:

• Non-Organ MIDI sounds (e.g. piano, harpsichord, strings, etc.)
• Pipe-Organ sounds from MIDI-driven sound modules (e.g. Wicks CM-100, Ahlborn Archive Modules, Walker Technical sound generation)

You will require amplifiers and speakers. The type, and number, of speakers and amplifiers will depend on the number and type of modules being used. For digital organ stops, the greater number of audio channels, the better. The reason is that more sound sources (i.e. speakers) there are the better it replicates the sound production coming from individual pipes.

Sometimes speakers can be placed in pipe-chambers behind swell shades.