Al,

I'll try to explain how the notes are played on the Amiga so you can
figure out how to handle them. If I'm unclear on any detail feel free
to ask questions.

The Amiga's audio DMA runs on a bus cycle of 2.79365E-07 seconds. (All
you really need to know about the Amiga's audio DMA for your purposes
is this number.) All the sample playback periods are based on this
number.

So the a table can be constructed of Amiga playback sample periods
with the following formula:

                              1
    Sample period=---------------------------
                  Sampling rate * 2.79365E-07

And you get the following table.

           C    C#   D    D#   E    F    F#   G    G#   A    A#   B
        ------------------------------------------------------------
1st Oct.| 856  808  762  720  678  640  604  570  538  508  480  453
        |
2nd Oct.| 428  404  381  360  339  320  302  285  269  254  240  226
        |
3rd Oct.| 214  202  190  180  170  160  151  143  135  127  120  113


This gives the values for the 3 octaves the Amiga can play from a raw
sample.

To get the sample rates in samples per second that you'll need you
use the formula:

                                    1
     Sample rate(Hz) =---------------------------
                      Sample period * 2.79365E-07
                      (from table)

So for a note C-2 the sample rate is 8363 Hz.

The fine tuning is accomplished buy adding/subtracting to the periods
taken from period table at playback. Thus you get this conversion
formula:

                                        1
     Sample rate(Hz) =------------------------------------------
                      (Sample period + Finetuning) * 2.79365E-07

(Finetuning value can be positive or negative)

MED and the newer Trackers can also use IFF instrument files which
contain a sample for each octave. With these instruments you use only
the playback rates from one octave but a different sample from the
file. This allows five instead of three octaves per instrument. The
IFF specifications should be available in the Pro/Am libraries.

-Mike