[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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