From: burd@hydra.unm.edu (Stephen Burd ASM)
Subject: Re: Kurzweil 1000 PX - sounding thin over upper middle range.
Date: Fri, 11 Sep 92 00:47:06 GMT
Organization: University of New Mexico, Albuquerque

Sorry for the long post here, my namserver can't seen to find nodename.dec.com.

In article <1992Sep9.233236.18146@funlwb.enet.dec.com> sullivan@nodename.dec.com (Greg Sullivan) writes:

>Hi,
>I have recently puchased a used 1000 PX, with PX A&B upgrades. The upgrade
>ROMs, according to the sales rep, are not from Kurzweil. I can't remember who
>manufactures them, but I could find out if required. I just wanted to order the
>A soundblock *only*, but he said that now the A & B come together.

I think Young Chang (Kurzweil) simply contracted with somebody else to
manufacture the sound blocks.  I doubt that your problem is
caused by either the A or B block since I don't think these
contain the piano sample.  This conjencture is based on the fact
that the original PX (8 button, no A or B ROMs) has the same
piano programs as the upgraded PX's.  Thus, I would assume that
the piano samples aren't contained in either of the expansion blocks.

>The problem is that over the upper middle, it sounds a bit thin - well,
>sometimes *very* thin. amd mainly while playing softly. It is not what I would
>.....
>To hear the offending sound - strike F4 with any velocity up to and including
>47, using the Stereo Extended Piano program. That's assuming I have the genuine
>Kurzweil samples - which I am starting to doubt. On this program, the sound can
>be heard from F4 to B4 (six notes). On the plain Grand Piano, I hear it from 
>B4 to D4 (four notes). The sound is kinda like a flute or clarinet. It does not
>pass as a piano to my ears.
>
>I have been told that 47 is a very low velocity. Well, it may be, but my RD
>sends 5 for ppp, and 127 for fff. I have got the PX to calibrate the velocity
>curve (where it asks you to strike a key ppp and then fff). I can quite easily
>play over the entire velocity range. I don't *think* this is my problem, but
>I'm not sure.
>
>Any help, insight, or advice much appreciated.


I just tried these notes on my PX+ and can clearly hear the problem with
the stereo extended piano.  I can't hear a problem with the Grand Piano,
however.  It sounds as if one of the sample points has been somehow corrupted.
The PX doesn't have a different sample for each note.  It has samples
at roughly each 4th note and transposes those samples for neighboring
notes.  Thus, a corrupt sample point would affect a small range of notes.
The extended stereo piano and the grand piano show different base samples
in edit mode.

The velocity variability is probably related to the fact that many of the
base samples are dual samples.  One sample is used for low velocity values
and the other is used for high velocity values.  For the grand piano, there 
is a 'soft strike' and 'hard strike' sample.  I assume this is the same
for the extended stereo piano due to the fact that the bad sound only
occurs at low velocity values.

To work around the problem, you might consider creating a separate 
patch using the grand piano sample and panning it from left to right to
enhance the stereo effect (note: according to the manual, the grand piano
already IS a stereo sample).  However, the extended dynamics will be
more tricky.  Some outboard equlization would probably be best, but you
might manage to gain some extended harmonics by patching in some additional
waveforms in the mid and high end.  Of course, this will substantially
reduce your polyphony.

-- 
FROM:      Stephen D. Burd			AT&T:      (505)-277-6418
USNAIL:    Anderson School of Management        FAX:       (505)-277-7108
           University of New Mexico		INTERNET:  burd@hydra.unm.edu
           Albuquerque, NM  87131

-- 
FROM:      Stephen D. Burd			AT&T:      (505)-277-6418
USNAIL:    Anderson School of Management        FAX:       (505)-277-7108
           University of New Mexico		INTERNET:  burd@hydra.unm.edu
           Albuquerque, NM  87131
Newsgroups: rec.music.synth