4 Oct
2009
4 Oct
'09
8:48 p.m.
söndag 04 oktober 2009 19:43:38 skrev Fons Adriaensen:
On Sun, Oct 04, 2009 at 06:50:38PM +0200, David
Olofson wrote:
Most likely the time elapsed from the first key switch is made to the second.
(IIRC from cleaning mine, the Fatars have the usual "bubbles" with conductive
rubber switches; two per key. I also had some small Roland controller way
back: Same design.)
Well, I don't know about linearity, or how
linear MIDI velocity is
actually supposed to be, but it's common to at least have various ways of
scaling velocity. Many (most?) synths will support mapping of velocity
per voice to create "analog" layers (crossfade rather than switch at a
distinct velocity), and to exaggerate, reduce or disable velocity
response and things like that.
The first question to ask is what is acually measured
and how, and with which resolution. Then a range of these values must be mapped to
0..127,
so the first thing to be decided is the limits of this
range,
I suppose 0 would be somewhere around where a real piano would make no audible
noise whatsoever, whereas 127 would be somewhere between where your fingers
start hurting and where the hardware breaks. :-)
This would be the absolute limits *before* mapping. One would most likely want
to map only a part of this range to MIDI velocity in the normal case. One just
wants to avoid random zero velocities when playing very softly, as well as an
obvious dynamic "brickwall" when playing real hard.
next what kind of function maps it to the MIDI range.
The original Studiologic MCU has two integer parameters for this in the user
interface; SHAPE [-4,4] and VELOCITY [1-8], where the former selects the
mapping function and the latter scales the dynamic range of that function.
Unfortunately, I don't know how this is related to actual key velocities, and
I'm quite sure one can't make it out from the instruction manual. ;-)
--
//David Olofson - Developer, Artist, Open Source Advocate
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