Re: [sdiy] MIDI isn

[jhaible at debitel.net]

> I'm not following your argument. First you said that it is necessary to use 
> data from several contacts per key. Now you seem to be saying that it 
> isn't. Actually, I have no idea what the different contacts are for. Are 
> they really used to shape an attack envelope, as you seem to be suggesting 
> above?

They are switching the different drawbars (i.e. harmonics) on a Hammond.
This allows some phrasing (as they don't close at the same point of the
key's way down), but this is different from a synthesizer's velocity that
only measures the time between two points of the key's way down.

If you only have the two points, you can make assumptions of the points
in between. One possible assumption would be that they come in equal distance.
If this assumption is right, the 7 extra data are irrelevant. If the assumption
is wrong (because for some reason the keys are played with a non-equal
spacing between the points), you'd have to transmit the extra data.
This will cost time, because you're transmitting the data in a serial stream.
How much time ? 9 data will take more time than 2 data. If you send
these 9 data as fast as possible (one immediately after the previous one),
you still have equal distance on the receiver side. So you
have nothing gained yet. Only if you spend even more time, you can
think of getting information about the relative location of the extra data.

(Of course you can think of a special protocol that doesn't transmit the
individual "contact events", but a clever format that contains information
about the relative location in an extra byte. But that's pretty far from
standard Midi, isn't it ?)

So I'm saying it is important *if* you want to preserve a Hammond's typical
"musicality", but you haven't gained anything if you transport these 9
messages in an equal distance (most dense data package). So it's pretty
useless to try it with Midi. (Not that I think it would be necessary to
try everything with Midi.)

JH.