Comment by butterflyhug
3 days ago
Re: Bach, also factor in that an organ player’s two hands would often be playing on two separate manuals (keyboards) that produced different sounds from each other and from the footboard. The player could activate a different set of stops (groups of pipes that provide a consistent sound for each note playable in the range of the keyboards) for each keyboard or footboard, and could also vary those selections to some extent during a piece’s performance.
If you look past conventional terminology, an organ really a single instrument in a similar way as a multi-input and multi-output synthesizer is a single instrument today — the difference is more that even a modern organ generally encodes most of the technology limitations of Bach’s time, whereas a computer-based synthesizer’s additional sound flexibility reflects the broader technology capabilities of our current times.
One nitpick: changing registration and playing on different manuals was not common in Bach's time; some scholars have gone as far as saying it was not done, even some pieces contain explicit instructions. But it's more of a Romance thing.
Many keyboard players will play stacked keyboards today - I've got a big Nord plus a bunch of little Reface keyboards, and they often each have their own pedals attached to control sustain, rotary speaker, etc. This is basically the same situation as what you're describing (except I'm not playing notes with my feet).