Music With A PLC

I've started playing with a fixed IO SLC500 trying to learn how to
program PLCs. I've worked in the control industry for some years, but
the programming part of PLCs is a new adventure.

I bought a few books, and have been searching the web for tutorial
information with some success, and am always on the lookout for useful
examples.

My latest project is trying to produce music with a plc. I have
constructed an octave of tubular bells that are struck by small
solenoids controlled by the plc. I've managed to produce short tunes
such as chopsticks etc., but the music sounds less than pleasing as I
haven't figured out a successful method for consistently producing the
timing necessary for different note values. In the interest of keeping
the program as short as possible (not too much memory on the PLC I
have). I configured three free running two part timers (one for tone
duration, the second for a short delay akin to moving a finger from one
note to the next) for 1/8th, 1/4, and 1/2 notes. I utilize the
individual note timing duration sequences as needed during the tune
rather than using a different timer with each note played.

Playing a series of the same note lengths works out well, but a problem
usually surfaces when switching from one note timing value to another
as the free running timers being of different lengths can cause a
clumsy sounding transition with small but noticeable timing errors at
the transition points.

My goal isn't necessarily to produce music (I've done rather poorly so
far :o)   ), but to learn PLC programming, and specifically timing
techniques at this point.

I've searched the net looking for examples of using PLCs to produce
music without any hits. I would appreciate any tips on web sites with
such examples or information, and/or suggestion as how I might use
timing sequences more effectively.

If there are News Groups more suited for questions of this nature I
would be interested in hearing of them as well.

Thank you for your time.