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        MIDI-OX >> Mapping Questions >> mapping lowest note of cord
        
(Message started by: jack1931768 on Mar 21^st, 2011, 6:56pm)

Title: mapping lowest note of cord
Post by jack1931768 on Mar 21^st, 2011, 6:56pm

I want to map only the lowest note of a cord
(on the bottom octave) to a diferent channel.

To simulate a pedal board.

Any Ideas ? :(

'some organs call this = Mono Bass '

Title: Re: mapping lowest note of cord
Post by Peter L Jones on Mar 22^nd, 2011, 8:36am

There's no such concept as a chord in MIDI. Everything is seen as individual events. So when you press a key, a "Note On" event is sent. When you press another, another "Note On" is sent. When you release them, you get "Note Off" events for each.

MIDI OX processes these events one at a time. It doesn't know, for example, that 20ms ago there was a "Note On" event four semitones below this one. That earlier event has been dealt with and is forgotten.

Thinking of it the other way around also reveals some problems.

* At T+0, no notes a pressed or held.
* At T+1 you press and hold middle C. Now, is this the "lowest note in a chord"? Not really, there's only one note held.
* At T+2 you press and hold A above middle C. Is this new event the "lowest note in a chord"? No, the middle C already held is... but that event has already been processed at T+1 -- it's too to do anything about it now.

You will never be able to look forward in time from T+1 to T+2 to foresee what events are going to take place. (Well, if you could, I'll get you to place my bets for me...)

You could write a program that monitors incoming MIDI events and remembers the last event that happened and decides what to do based on two events, rather than just the current one.

Alternatively, allocate a key range to be the pedal board and map that.