Midi is an acronym for Musical Instrument Digital Interface, and as the name suggests it is a standard way to interface musical instruments to digital equipment.
Midi is the current standard for digital musical instruments. In essence it is a signal that describes the state of the accordion or instrument. This signal is then interpreted by an expander, sound generator or computer to produce extra sounds, drum loops or even to record a performance with great accuracy.
To achieve a good midi system the following components are needed: Midi output on the instrument (accordion), Midi expander or computer with high quality sound card, Amplifier and speakers or a good quality home stereo system.
Midi is normally transmitted on 16 channels, although some more advanced expanders accept up to 32 channel midi signals. Each channel is usually designated to one part of the music. For example on the accordion usually Channel 1 is designated to the right hand, Channel 2 to the chords and Channel 3 to the bass. Other parts including drums and extra instruments are usually assigned to other channels. The standard drum channel is normally Channel 10.
GM or General Midi is the description of the standard midi format, which includes 128 standard instruments and patch changes including effects such as Chorus, Reverb, Pitch bend, Sustain, etc. A table of GM sounds can be found here. The drum map can be found here.
Effects can be applyed to any of the channels, these effects will only affect that channel, and so can be applyed to one part specifically, e.g. sustain on the right hand channel 1.
These note signals and effect signals are interpreted by a midi expander, which generates sounds for each of the channels. For example Violin may be set on channel 2, which means that all signals sent to the expander on channel 2 will produce a Violin sound. You can then add effects to the violin.
The expander will usually emit the sound signal in stereo phono or jack sockets which must be connected to an amplifier. Different channels can be sent to different stereo lines, or split differentially between the audio stereo output.
We specialise in midi equipment, specifically midi accordions, normally carrying a stock of reeded and reedless midi accordions. We have the ability to source or manufacture nearly any midi device, from state of the art expanders to simple channel splitters.