Music
307
Lab
4: FM synthesis, patch editing
When the Yamaha DX7 FM synthesizer appeared
in 1983, it took the world by storm—the DX7 was by far world's
most successful synthesizer up to that point (and by number of units
sold, probably still is!).
Although it is now an "ancient" synthesizer, there
are still hundreds of thousands of them still in use throughout
the world. The DX7
can make a wide variety of sounds, but it is notoriously difficult
to learn how to program it.
This is because FM is an inherently non-linear synthesis
technique, and also because the parameters of synthesis are too
hard to manipulate using the buttons and tiny display on the synth.
The way to make patch editing of any MIDI
synthesizer much more tractable is to put all the parameters on
the computer screen at once (including graphical envelopes), instead
of using the tiny display that is on the synth.
This kind of editor is now an industry standard, but it was
not always so. The first patch editor ever
created was for the DX7, written by David Zicarelli on the Macintosh. It was a major step in "virtual
interfaces" to music equipment in general, and it was the prototype
for Galaxy, Steinberg, and many others that are common today.
To create new voices on the DX7 was beyond the
reach of most musicians. It
was extremely rare to find anyone who knew how to do it. Although the patch editor does not
substitute for understanding the theory behind FM, it makes it possible to
program the DX7 family or TX802 fairly easily. All parameters are visible and changeable directly from the
screen of the computer. Note that
when you do this assignment, you are NOT editing sounds, as you did in the
previous assignment. You are
instead editing the parameters
of synthesis, which change the sound the synth produces.
Create at least FOUR different voices
using the GALAXY patch editor. Store them in a folder with
your name on it. Describe
in English what you did and why you think your patches sound the
way they do.
Note that you don't need to have four different
files; it's much simpler to just use the first four "slots"
in one voice-librarian bank of 64 voices to put your new voices
in. You can rename them by selecting "Enter Names"
in the Edit menu, clicking on the "INIT VOICE" text, and
typing in a new name. Of
course, you can have a lot more than four you could make 64
new voices in each bank.
How to use the GALAXY/TX802
patch editor:
0. Select performance 17: "MU307" on TX802
synthesizer
Check that audio from
TX802 is going into the little speakers.
1.
Select
Galaxy from the Apple Menu
2. To test that you re sending MIDI to the synth, select
TX802 in the pop-up window in the keyboard, and then click on
some notes. You should see the red
light flash on the TX802 on the first button. You should also hear the sound if you have audio set up correctly.
.
2.
Select
"New Bundle" from the File Menu (you can also select "New
Bank," this will end up being the same thing). A "bundle" is a collection of banks, like
tuning, performances, etc.
You will only be editing voices
for this assignment (you can edit other things if you want to).
3. Select "TX802" and click OK.
4. Double-click on
"voices" You will see a
window with 64 "INIT VOICE" slots.
5. Select voice 1, then click on "edit" in the
upper-right-hand corner of the window.
6. This will bring up the meat-and-potatoes: the patch editor. You will be creating
your voices here. Note that you
have many choices. The
choice of algorithm (1-32), editing six different envelopes, the on-off switch
for each oscillator, the course and fine freqs of each osc, the frequency of
each oscillator as fixed (f) or ratio (r), and the output level of each
oscillator, for starters. With
just these parameters, (not to mention many others) you can create a vast variety
of sounds.
7. Note that you've got a whole bank of 64 "init
voic,"patches, which are pure sine waves, the most simple sound
it is possible to make. In
sonic terms, this is a "blank slate."
If you want to examine an existing voice, to learn more about
how these sounds are really constructed, you can say "Get voice
from TX802" in the Load/Send menu (after selecting an interesting
voice from the synth.
8. Save your voices in the bank, and quit the program. Next time you can just doube-click
on your own file to invoke the program.
9. Note that there is a difference between "Performances" and "Voices" on the TX802 (and
indeed in some form on almost all polytimbral synths available today). You are only supposed to edit
voices. However, on
the front panel of the TX802, there are different performances,
which are configurable. Pick
a performance (by pushing the + or - buttons on the front panel)
that have only one or two red lights on.
This means that you are editing a voice that can be polyphonic. If you try to edit a voice with all 8 lights on,
you will become confused, because you might not be listening to
the voice you created. The
lights refer to "partitions" of the 16-voice polyphony
-- remember the difference between "multi-voice" (=polyphonic)
vs. "multi-timbral" (more than one type of voice simultaneously).
You are editing one voice at a time, and you don't want or
need multitimbral for this work.
Each red light refers to a different timbre.
Note: for all lab assignments, you must HAND IN A WRITTEN PAGE(s)
DESCRIBING YOUR WORK
(Musical materials, tracks, problems (if any), strategy, etc.)
You won't get a grade if there is no writeup!