Docs for YAMV_ED.PRG:

This program is set up for a Yamaha PSS-480 or equivalent (I'm not sure
about the 680).  It is completely GEM Based so DA's should work and it
was written in GFA Basic 3.07.  You must have a color system since it 
will only run in medium resolution.  I recommend the ST's default color
palette, although a custom palette should work also though the text may
come out strange.

The program works in 2 modes:

Mode 1: There are 4 menus that correspond to different voices and styles.
        Use the right mouse button to change the menus and use the left
        button to select a voice or style.  The display on the Yamaha
        synth should indicate what was selected, either the tempo changed
        due to a style selection or the voice changed.  This mode simulates
        entering a selection from the synth itself.  The advantages are
        that you only have to click a button instead of entering a 2 digit
        code.  Picking a selection from the monitor display is also easier
        since its easier to read than the small print on the synth.  When
        you left click on a voice or style, the color will change.

Mode 2: This program has an automation feature where if you make selections
        via the EXECUTE menu, every voice preset and/or style preset 
        selection will be stored in order to play the synth real-time with
        the various selections automatically being sent at some user-
        specified time interval.  I've used terms from "fastest" to 
        "slowest" because the time changes slightly when you increase the
        tempo on the synth.  The program will ask for total # of presets
        and the time interval between selections.  You can then select
        from the Voice and/or Style Menus with the right/left buttons.
        Towards the top-right corner (I've allowed room for a corner clock
        if you've got one), is a display of current # of presets thus far.
        It will say 'Done!' when you reached the total.  At this point,
        you can view what you've selected and then Play a tune.  The 
        PSS-480 should be in Keyboard Assign Mode since you really can't
        do to much with it in Sound Source mode (which is used with 
        commercial sequencers or playing songs with predefined presets).  

This program is freeware!  I'm not really a programmer but I like to dabble
from time to time.  Known bugs are: Viewing more than 1 session - you may
see more selections than what you've programmed, the other bug I know is
only in the compiled version - sometimes when you leave a routine you may
get a blank screen.  Ususally just clicking the left or right mouse button
will get you back to the GEM menus.  The Multidesk Accessory sometimes 
screws up also.

I've included the source code so you can 'dabble' to if you like.  I'd 
appreciate any suggestions from you experienced programmers. I may upgrade
this program to allow for GEM file selecting and save or load the selections
you created to disk.  Have fun! Enjoy!

Notes on the PSS-480 synth:

Even though this is one of the cheapest synths, with MIDI and your Atari,
it really performs well.  Most commercial sequencers work fine (I 
recommend Dr. T's Graphical TigerCub and KCS Level 2).  Just make sure
to use the echo feature or MIDI merge when in mode 99 (Sound Source) in
order to be able to program predetermined voice presets.  I've also 
downloaded a SYSEX program off of GEnie that allows you to save the song
memory, voice banks, and custom drummer info to disk.

As far as patch librarians, I use PixelPro's Superlibrarian to manage all
patch data.  With this program, you can send or receive patches that you
create with the on-board digital synthesizer.  You can name them and 
describe all the synthesized characteristics and eack patch is only 64
bytes apiece so if you can store alot on 1 floppy and a ton on a hard
drive.  You can also send or receive custom drummer data (or any SYSEX
data) without having to do a whole SYSEX block dump.