VFX frequency resolution

>Steve Curtin of Ensoniq has informed me that the pitch resolution of the VFX
>line is not 768 steps per octave, as he originally stated, but is in fact
>512 steps per octave. This seems correct given my expereince that the
>nominal size of an interval needs to be incremented by usually 2, sometimes
>3, cents before the rate of beating changes.

This point needs some clearing up. I'm sorry that Paul ended up buying a
used Ensoniq synth that had less frequency resolution than I originally
thought. The reason for this is that the VFX used an early version of our
oscillator chips that only had a 9-bit frequency fraction, so that although
the tuning was stored as 768 steps per octave, the hardware frequency
resolution was only 512 steps. This was substantially improved in the case
of the OTTO chip which is used by all our synths and samplers since '92 or
so, specifically because because the VFX did not have the frequency
resolution to do pitch envelopes without stepping and zipper noise. OTTO
has an 11-bit fraction, which is 2048 steps per octave at unity. As has
been stated here before, this resolution doubles with each octave transposed
up and halves with each octave transpose down. The tuning maps into an
exponential table, which is stored as 128 steps per semitone or 1536 steps
per semitone.

regards,

Steve Curtin
Ensoniq Corp


Received: from ns.ezh.nl [137.174.112.59] by vbv40.ezh.nl
with SMTP-OpenVMS via TCP/IP; Tue, 8 Oct 1996 17:17 +0200
Received: by ns.ezh.nl; (5.65v3.2/1.3/10May95) id AA00444; Tue, 8 Oct 1996 17:18:35 +0200
Received: from sun4nl.NL.net by ns (smtpxd); id XA00442
Received: from eartha.mills.edu by sun4nl.NL.net (5.65b/NLnet-3.4)
id AA04130; Tue, 8 Oct 1996 16:49:09 +0200
Received: from by eartha.mills.edu via SMTP (940816.SGI.8.6.9/930416.SGI)
for id HAA29062; Tue, 8 Oct 1996 07:47:39 -0700
Date: Tue, 8 Oct 1996 07:47:39 -0700
Message-Id: <199610081047_MC1-A99-F743@compuserve.com>
Errors-To: madole@ella.mills.edu
Reply-To: tuning@eartha.mills.edu
Originator: tuning@eartha.mills.edu
Sender: tuning@eartha.mills.edu