Patches and discussion for Ensoniq VFX family

Just a few comments to clarify some issues for you..


--- In Ensoniq-VFX-SD@egroups.com, Nathan I Smutz <n.smutz@j...> 
wrote:
[snip]

> Modulating pitch with the pitch bender or another source (mod wheel 
in my
> case) does not have the same effect as just transposing the pitch 
down on
> the "Pitch" page.

This is common to almost all digital synths and samplers - the reason 
being that the transpose affects the note 'value' going into the 
playback engine, whereas a pitch bend will generally affect the pitch 
AFTER its gone into the first part of the engine. As such, the 
transpose will correctly chose the sample/d.oscillator assigned to 
the resulting key, whereas bending down an octave, will play the 
sample/d.oscillator from the ORIGINAL key, pitch shifted down an 
octave.

There is another situation where this also applies, when you're using 
mono/legato notes, and you strike a second note, it will be the first 
note's sample/d.oscillator shifted to the second key (this is 
actually a major problem for implementing legato on digital synths 
and samplers - and one of the reasons that legato mode is often 
tacked onto samplers in later firmware releases)
 
> 
> Well I got to exprimenting.  I set the mod wheel to modulate pitch 
on the
> "Pitch Mod" page.  As you get into the higher numbers for "MODAMT"
> (modulation amount),each increment broadens the range of the mod 
wheel by
> somthing like a semitone.  The smaller numbers (1,2,3, etc.) seem 
to be
> closer together, i.e. to bend an octave with the wheel the setting 
is
> +/-62 after that each octave is 12  numbers away.  You will have to 
go to

This is because the modulation matrix is (usually) 'linear', ie, the 
modulation applied is a linear value, whereas the pitch of notes are 
logarithmic. I believe there is a log mod function if you go thru the 
modulation 'math' section on the VFX series (i don't have my SD1 in 
front of me, so I don't recall the exact wording of the button 
Ensoniq assign to it, but you can apply curves and sumation of two 
modulation sources)

> the "Pitch" page (not "Pitch Mod") and fine tune to standard pitch. 
> Also, once you've bent the pitch down you might want to transpose 
the
> patch up to the octave you started with.  
> 
> Bending an octave down makes the sound less bright but it sounds
> different than lowering the filter cutoff.  The sawtooth wave I was
> working with got less buzzy.  Buzzyness could be heard on the unbent
> patch when the filter was turned way down.

Again, see above, you're actually playing back the waveform for the 
original key, except that its pitch shifted down an octave. If you 
had an external pitch shifter module, this would give you roughly the 
same effect. When synth designers produce the multi-sample set for a 
synth the timbres of the samples across the keyboard vary 
to 'balance' the timbre as a whole. This is especially true of 'real' 
sampled instruments, where there is usually a natural change in the 
characteristics as you play different notes - for example, a bass 
note and a treble note on a piano sound vastely different in terms of 
timbre.



> What happens whe you bend up an octave?  The sound gets brighter.  I
> suspect this is again a different sound than you would get 
adjusting the
> filter.

Same deal, again the timbre is different between, say, a C2 piano 
sample shifted to C3, than a C3 piano sample.

As to the filter, you COULD construct a filter (in an ideal world, 
with a totally customisable filter set) that would mimic the same 
timbre. Whether the filter on the VFX is up to such a task, I'm not 
sure, and working out the filter characteristics would take hours of 
trial and error...

[snip]