Zipper Noise  (not to be confused with the pops and clicks at the end
of a sample associated with inaccurate .wav to EPS conversion)

Q. What is that *DINK* noise at keyup on bass samples?

A. What you are hearing is zipper noise with the digital output filters
(not to be confused with the programmable filter) of the EPS. The
output section of the EPS is primitive as well, which contributes to
the noise. 

Zipper noise is just quantinzation errors. It is bound to show up on
low notes, which makes your sample a perfect candidate. Low frequency
notes require more resolution, since there isn't much change in
amplitude from sample to sample. Thus when you release a note, the DOF
uses fewer and fewer bits to resolve the sample as it releases. 

This is apparent if you set the AMP release to 0 - then it's a bright 
obvious CLICK which is totally unacceptable. 

There is a solution: 

1) Set the ENV3 release (TIMES= 0,64,52,40,X <set the X>) to a long
enough release to eliminate the zipper noise. This way you relax the
demands on the output filter, but of course you want the sound to
release quicker. 

2) Set the filter: MODE F1=3/LP F2=1/LP, CUTOFF F1=0 F2=0
                   ENV2 AMT F1=+99 F2=+99

3) Set the ENV2 times to 0 0 0 0 X; X being the desired release time. 

What is happening here is that you are taking the stress off the DOF
and doing the releasing within the programmable software. The 16-Plus
has the same problem, but the ASR is designed with adequate DOFs as
to eliminate the zipper noise.

I quoted Garth at Rubber Chicken for a good part of this.
http://www.chickensys.com

SampleStation
http://geocities.com/Area51/Comet/6730/index.html
Mark Rinewalt-1999