🚀 go-pugleaf

Why do I SOMETIMES get poping sounds at the beginning and end of sounds
on my IIcx?  For example if I go into the sound cdev and switch amongst
beep sounds then SOMETIMES the newly selected sound will play with an
initial pop, and sometimes it will play fine.  If I play sounds from
hypercard I get the same sort of effect.  NOTE: if I issue one "play"
command that plays several notes:

  play "Harpsichord" d3 c4 f2 g5

then I only get popping sounds (sometimes) at the beginning of the
first note or the end of the last.  I also don't seem to get any pops
when I continually reselect the same beep sound in the sound cdev.
The problem is not just with switching sounds, however, since repeated
hypercard calls of "play "Harpsichord" c4" WILL play poppy.
It doesn't seem to matter what sounds I use.  It's not a speaker 
problem either, since it sounds the same when amplifying the sound 
port output.

Questions:
  1) Is my machine (sound chip?) defective?  
  2) If not, are there work-arounds/fixes?
  3) Is this a known problem?

Thanks for any and all responses!  - Lee  (spector@brillig.umd.edu)