MOTM

Since there has been discussion prior regarding zipper steps when 
using the ExpressionMate I did record an mp3 of it driving my MOTM-
300.  I scaled the output to 5 volts (from 10 volts scale on the
PSIM) so I could stay within audio range.  It's pretty smooth although 
that's depends upon how smoothly I moved my finger (it's amazing what 
effect recording has on your coordination!).  There are some slight 
discontinuities where they piece together the three independent 
ribbons.  You can hear one of them right at about 5 seconds into the 
file.  It's simply expressionmate.mp3 in the files section.

I also went through the PAiA source and they do just throw away the 
bottom 7 bits.  It's an 8 bit DAC driven with the higher seven bits
of pitchbend data.

Dave


--- In motm@yahoogroups.com, "djbrow54" <davebr@e...> wrote:
> I wrote the code to take the Expressionmate MIDI and convert it to 
CV 
> with the PSIM.  I know the Expressionmate is a full 14 bits of 
> pitchbend data which is quite smooth.  I translate this full 14
bits 
> across 0 to 10 volts in the PSIM so the increments are limited by 
the 
> 12 bit resolution of the PSIM.
> 
> I designed my own module using a PAiA MIDI2CV and it does exhibit 
> considerable zipper effect.  I haven't gone through the PAiA code 
but 
> I can only guess that they are ignoring the the lower 7 bits
(second 
> data byte) or the DAC resolution is just too low.  With the PSIM it
> is 
> quite smooth.  I also have another module that I use with the PSIM 
to 
> level shift the outputs back to 0 +/- 5 volts.
> 
> Dave
> 
> 
> --- In motm@yahoogroups.com, ivancu@a... wrote:
> > From: "djbrow54" <davebr@e...>
> > >Another option is the ExpressionMate.  I know it is expensive
> but I 
> already have one.  I've
> > >written the code for the PSIM to adapt the MIDI to basic CV 
> functionality.  The 
> > >ExpressionMate can also be used as 3 separate ribbons and it 
> shouldn't be too hard to 
> > >modify the code to support this.  I'll get around to it one
day.
> > 
> > How do you get continuous smooth CV changes out of the 
> Expressionmate?  I had one for a week and was disappointed that it 
> would do a glissando instead of a smooth portamento as you slid up
> and 
> down the ribbon.  Of course MIDI outputs note information so it
> wasn't 
> surprising.  But it would have been nice to have an interpolated 
> output that would give continuous up and down gliding over a five 
> octave (or more) range.
> > 
> > Ivan