Why are there so many more inputs on the EZbus than there are audio channels?

In a typical computer-based recording environment, many of the audio sources (keyboards, sound modules, drum machines, effects devices, and the like) require little or no processing “after the fact;” that is, they don’t necessarily need to have their tone, volume, or pan positions controlled at the mixer level. Rather, these functions can be performed by the device itself via internal settings or in response to MIDI commands. In that scenario, all that’s required of the mixer is that it provide a means for the audio from the device to be brought into the main mix.

The EZbus was designed to accommodate a large number of audio sources, not all of which would necessarily need to have their individual tone, volume, and pan positions controlled at the mixer level. On EZbus analog inputs 5, 6, 7, and 8, three input jacks (labeled A, B, and C) are provided for each input. The three jacks in each channel are summed (and electronically buffered), allowing you to connect up to three audio sources to a single input. You could, for example, bring the signals from six synthesizers into inputs 5A, 5B, 5C, 6A, 6B, and 6C. You could then bring the stereo returns from three outboard effects devices, for example, into inputs 7A and 8A for effect #1, 7B and 8B for effect #2, and 7C and 8C for effect #3. All together, that’s 12 audio signals brought into the EZbus using only four audio channels.

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