[sdiy] FW: Make a CS80

[Jerry Gray-Eskue]

-----Original Message-----
From: Jerry Gray-Eskue [mailto:jerryge at cableone.net]
Sent: Monday, April 05, 2010 8:09 AM
To: Synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Make a CS80


 Midi also has support for Several unassigned Controllers, these can be used
to transfer a lot of additional information like key position, the key
pressure is already there as After touch. Velocity is usually used for this
type control as absolute key position is more difficult to control than
velocity of key action. However if desired you can support both as well as
several other controller values like side to side pressure, or front to back
pressure.

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of Tom Wiltshire
Sent: Monday, April 05, 2010 5:51 AM
To: cheater cheater
Cc: synth-diy
Subject: Re: [sdiy] Make a CS80



On 5 Apr 2010, at 11:00, cheater cheater wrote:

> I think that it would be nice to have both a proximity/position sensor
> (hall?) for reading how far the key is depressed, and a pressure
> sensor at the end of the travel, followed by a final high-pressure
> tactile switch that presses in when the pressure sensor is at the
> maximum.. that could make for some interesting playing techniques
>
> For example you could control a pan flute sound, and the position
> sensor could fade in more 'breath' as you're depressing the key. Once
> the key touches the pressure sensor (which could have a metallic
> terminal with a matching terminal on the key body to tell when the key
> is there) the resonance could start happening and the pressure would
> control the crossfade between the breathy sound (making it decay to
> 30% at maximum pressure) and the resonance (making it raise to 100%).
> Then the tactile switch would completely decay the breathy sound to 0,
> via a 15ms release time.

You've got some good ideas, but you don't half make things complicated.
If you've got a pressure sensor already, what's the need for contacts
to detect whether the key is touching it, or a high-pressure switch
at the maximum pressure. Both 'switches' can be implemented as
thresholds on the output from the pressure sensor. A zero reading is
"key not touching", <5units is "key just touching", and >95units is
"maximum pressure".

> Or you could have a violin style sound where the string gets bowed
> when you're depressing the key, then the pressure heightens the
> vibrato, and the tact key plucks it and the sound is over; this could
> be used by quick-handed players to have control between
> bowing/staccato/pizzicato.
>
> This scheme doesn't even exclude the additional information of
> velocity, but definitely gives it a new context, and it could be used
> for something else yet to give even more expression to the sound..
>
> Had only MIDI not happened, we'd have hundreds of synths like that
> since the 80s.

And they'd all use some proprietary protocol and none of them would
talk to any of the others - great!

I realise you have a deep-seated hatred of MIDI, and I agree it is
getting a bit long in the tooth, but it did a great job. Standard
wars are an absolute PITA for end-users (How many different IR remote
controls do you have in your lounge?! Why didn't *they* find a
standard to work to?) MIDI meant that you could buy a keyboard from
any manufacturer and be sure that it would talk to equipment made by
*any* other manufacturer. It made the whole computer-music bedroom
studio thing possible, and opened up a whole world of options. There
are many things it doesn't do, and it is a bit keyboard-centric, but
it was an incredible effort given the time it was done.
Anyway, speed was always MIDI's biggest weakness, and with MIDI-over-
USB, that's becoming a moot point. It may yet live into the 21st
century.

T.


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