Audio Noise Problems (IIgs ROM 01)

["Tempest" <tempest@atariprotos.com>]

Yesterday while using my IIgs I noticed a strange noise coming out my
speakers.  It seems that whenever I was in System 6 there was a quiet
poping noise coming out the speakers.  The pops were about a second
apart and it was constant. Opening menus or moving the mouse around
didn't seem to change anything.  I don't recall ever having this
problem before, so I'm wondering if something I've setup recently could
cause this.  The problem doesn't happen during games, so I think it
must have something to do with System 6.

I've got a IIgs (ROM 1), system saver, monitor all stacked on each
other (in the standard way).  Next to the IIgs I have a HD with a CD
stacked on it, with two 3.5" floppies stacked on those. On top of those
floppies is a speaker, with the other speaker being on the desk on the
other side of the IIgs.  Inside the IIgs I have an Ethernet card, SCSI
card, 4 MB memory card in the aux slot.

At first I thought that the speakers might be causing the issue, but I
moved them far away from the IIgs and still heard the sound.  I had the
3.5" drives and HD/CD drives next to the IIgs before and never had this
issue, so I'm at a loss on what it could be.  Perhaps the speakers are
picking up some kind of interference from the HD reads?  I don't know
if the pops come out the internal speaker when I unplug the powered
speakers, if it does it's too quiet to hear.

Another theory I had is that this is the dreaded ROM 01 noise issue.
I'm going to try and hook up my ROM 03 tonight and see if the problem
is still there, but I thought that when this was the problem moving the
mouse around and selecting menu items made it worse.  I don't get this
with my problem.

Anyone have a similar issue or have any ideas on what it could be?