[Coco] music synth on speed

[Bob Devries]

I wonder how many other undocumented features there are in the Orchestra
90/cc?
--
Regards, Bob Devries. Dalby, Queensland, Australia.
Faith isn't faith until it's all you're holding on to.
http://e4god.com/freeblogs/bdevries/


----- Original Message ----- 
From: "Kevin Diggs" <kevdig at hypersurf.com>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, October 23, 2004 9:48 AM
Subject: [Coco] music synth on speed


> Hi,
>
> If you want to run your synth at high speed:
>
> <div class="moz-text-flowed" style="font-family:
> -moz-fixed">ORCHESTRA-90/CC WITH FAST COCO
>
> By Bryan Eggers
> Software Affair, Ltd.
>
>
> YOU MAY BE ABLE TO RUN YOUR
> COCO AT DOUBLE-SPEED TO ENHANCE
> THE MUSIC QUALITY OF TANDY'S
> ORCHESTRA-90/CC MUSIC SYSTEM -
> BY USING AN UNDOCUMENTED
> COMMAND IN THE CARTRIDGE!
>
>
> IMPORTANT:
>
> READ THIS ARTICLE COMPLETELY
> FIRST!!!
>
>
> The quality of sound produced
> by any digital synthesizer is
> directly proportional to its
> sampling rate. The sampling
> rate is primarily determined by
> the efficiency and clock rate
> of the host processor. Tandy's
> ORCHESTRA-90/CC is no exception
> to this rule. The 6809 used in
> the Color Computer is certainly
> one of the best processors that
> could ever be used for music
> synthesis, and we are very
> happy with the sound produced
> by the ORCH-90/CC when used on
> a standard Color Computer at
> normal speed.
>
> Many Color Computers will run
> at TWICE the normal speed, and
> will do so without any hardware
> modifications whatsoever. If
> you are lucky enough to have
> one of these computers, you can
> enable your CoCo's faster clock
> by using a special undocumented
> command from within ORCH-90/CC.
> This will make a significant
> improvement in the overall
> sound quality produced by the
> ORCH-90/CC music synthesizer!
>
> Using the faster speed lets you
> play in 4- and 5-part harmony
> and almost never worry about
> aliasing. The ORCH-90/CC will
> automatically make all tempo
> and transposition adjustments,
> resulting in a better sound
> quality improved by the higher
> sampling rate. You can play
> higher and cleaner notes, and
> define more partial harmonics
> than were possible running at
> normal speed. Best of all, it
> won't cost you a cent to try
> it!
>
>
>    ****** IMPORTANT ******
>
> Tandy designed the Color
> Computer to operate at NORMAL
> speed, not at double speed!
>
> Tandy does not in any way,
> shape or form, support,
> warranty or otherwise guarantee
> that the Color Computer will
> run at any faster speed!!
> Therefore, if your system does
> not run reliably at double
> speed, you CANNOT blame Tandy!
> Do it at your own risk. You are
> attempting to run your system
> outside of published specs, so
> keep that in mind. If your
> system does not run at
> double-speed, it does NOT mean
> that you have a defective
> computer or a defective
> ORCH-90/CC cartridge!!!
>
>
> ENABLING THE FASTER CLOCK
>
> In an effort to make sure that
> no one would accidentally
> invoke the undocumented
> command, and perhaps lock-up
> their system and get totally
> confused, we devised a special
> keystroke sequence that must be
> followed exactly.
>
>
> STEP 1
>
> When you first plug in
> ORCH-90/CC and turn on the
> computer, you'll see the
> copyright and licensing
> information. Before pressing
> any other keys, hold down the
> <SHIFT> key and press <ENTER>
> once. The demo tune is
> displayed. Other than that, it
> didn't look like the command
> did anything special, did it?
> Well, that keystroke toggles an
> internal switch that now gives
> you the OPTION of using the
> speed-up command along with
> certain other commands. In
> other words, by configuring
> ORCH-90/CC with this initial
> keystroke of <SHIFT><ENTER>,
> you're telling the system that
> you MIGHT use the special high
> speed enable command. But,
> unless you press these keys
> when you first turn on the
> system, you will not be able to
> use the speed-up command at
> all. We expect that this
> special way of configuring the
> system will prevent any
> accidents.
>
> The <RESET> button has no
> effect whatsoever on this
> feature. If you press <RESET>
> later to break a printer
> lockup, for example, you'll
> still be able to use the
> speed-up command. By the way,
> you can press <RESET> at any
> time without losing the current
> music file in ORCH-90/CC's
> buffer.
>
>
> STEP 2
>
> At this point, all commands
> still work normally. Keep in
> mind that you only need the
> fast clock during the actual
> playing of a song. The normal
> clock rate provides plenty of
> speed for all other features.
>
> The commands that we let you
> enhance, therefore, are the
> GET, PLAY, and MULTI commands,
> since they are all used to play
> music. These commands are
> normally followed <ENTER> to
> execute the command. An
> optional string of filenames
> may also follow these commands,
> also eventually terminated by
> <ENTER>. All this is normal
> operation so far.
>
> Everything works normally until
> you use <SHIFT><ENTER> instead
> of <ENTER> to terminate these
> commands! Using <SHIFT><ENTER>
> instead of <ENTER> enables the
> fast clock mode and executes
> the desired command
> simultaneously!
>
> For example, suppose you wanted
> to play the three files BACH,
> BACH2, and XYZ. Normally, you
> would type:
>
> G BACH BACH2 XYZ <ENTER>
>
> But, to play the songs with the
> faster clock, you'd type:
>
> G BACH BACH2 XYZ <SHIFT><ENTER>
>
> The system would load and score
> each tune automatically, then
> just as it begins playing the
> tune, ORCH-90/CC switches your
> system's clock to high speed.
> The fast clock is turned off at
> the end of the tune, and the
> system loads the next tune,
> plays it with the fast clock,
> etc.
>
> As another example, you could
> type:
>
> M * <SHIFT><ENTER>
>
> This MULTI command, combined
> with the "*" wildcard
> character, will automatically
> play all songs on the disk,
> switching to the fast clock
> while playing each!
>
> You could still execute any
> of these commands with <ENTER>
> to play the tunes normally.
>
> Same is true of the PLAY
> command (P). Just use:
>
> P <ENTER> to play the current
> tune normally, or:
>
> P <SHIFT><ENTER> to play the
> current tune using the fast
> clock.
>
>
> IF IT WORKS...
>
> If your system can run reliably
> at double speed, the screen
> display will temporarily blank
> out while the music file is
> playing, sounding even better
> than before. All available
> processor time is now used
> for synthesis - no time for
> screen displays. This is a
> side-effect of the way the CoCo
> hardware handles the speed-up,
> not a problem with the
> ORCH-90/CC cartridge. Sorta
> makes an interesting light
> show, though!
>
> After the music finishes
> playing, the speed is switched
> back to normal, the screen
> image is restored, and the
> music file has not been lost.
>
>
> IF IT DOESN'T WORK...
>
> If your system can't handle the
> faster speed, the results can
> be unpredictable, but usually
> one of the following will
> happen:
>
> (1) The system locks up.
>
> (2) Screen fills with garbage.
>
> (3) The music plays OK, but the
> file in memory is now full of
> garbage when you return to the
> editor. You can still use your
> CoCo to play music with the
> fast clock, even with this
> problem, but if you are editing
> or creating files, remember to
> save your music file to disk
> BEFORE playing it!). You'll
> have to test your system
> thoroughly to make sure that
> the music file itself remains
> intact.
>
>
> If your system doesn't run
> reliably at high speed, it may
> be possible to modify it to do
> so, but that is a project for a
> real hardware expert. You might
> check with your local user
> group for such a person. Also,
> check the ads in the CoCo
> magazines. You might find
> someone who can supply or
> install a modification for you.
> Let us know what you find out
> and we'll post it in the
> database! If you really
> like music synthesis, any
> effort it takes to get your
> system running at double speed
> will be worth it in terms of
> the enhanced sound quality.
>
> </div>
>
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