On Mon, Dec 17, 2018 at 08:42:49AM +0100, Richard van Bemmelen wrote:
> I changed the vibrato depth kvdpth to a fixed, low value (0.1) and then it
> sort of worked.
> It looks like the algorythm is a bit unstable, because when I play the midi
> keyboard with very low velocity, the high pitch note returns...
> Almost like a resonant peak.

Aagghh!  I see what it is!  Csound can be so good at misdirection... (:-))

First, it seems that a kvdpth of 0 is what causes the fixed note.
This happens whether called from score or MIDI.  It doesn't seem
to matter how small it is to work, as long as it's non-zero.
(I'd guess this is probably unintended, but it should at least be
mentioned in the manual.)

But the hidden gotcha was the statement "kvdpth line 0, p3, .1",
which doesn't exactly work in a MIDI-triggered instrument!  I was
actually a bit surprised to see that it returns only zero, even
if the ramp is actually, say, "kvdpth line 0.1, p3, 0.2".

If you want a varying vibrato, I guess you could use linseg
with a fixed time (not 'line' as it rises indefinitely!), e.g.:
 "kvdpth linseg 0, 1, .1"

(I can't replicate your low velocity effect, though.)

	-- Pete --

Csound mailing list
Csound@listserv.heanet.ie
https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
Send bugs reports to
        https://github.com/csound/csound/issues
Discussions of bugs and features can be posted here