Is it possible ?????

[The Dark force of dance]

Y-ellow Boris 'n' all.

At 04:14 PM 10/7/97 +0100, Boris ROUSSEAU wrote:
>The MC303 is a numerique synth ... with only 2 output ... left
>channel,right ..
>Do you think it 's possible to transform it ? for have more channel output ...
>I've see this message in the groove-list...
>What do you think about it ?

Err let me see. The MC303 is one o' them digital TB303/808 clone things. I'm
not sure I had a play with a couple o' these things a while back. Just can't
remember which is which.

However, the short answer is. "No! Not easily". In fact it'd be bloody
difficult. Especially if with the assumed lack of documentation that is
usually not provided with these things.

These days, most digital audio is standardized to I2S bus. It stands to
reason because there are an abundance of cheap audio codecs that talk this
standard. In fact, even though there are variations on the theme, this is
the _ONLY_ standard for digital audio. It stands for IC Interstage Sound BTW.

It is a standard 3 wire serial interface. Much easier to deal with than
S/PDIF or AES/EBU. Basically it consists of a data line, a clock line and a
signal called "WORD clock" The word clock flips over every 16 bits or so. In
one position it says. "This data is the left channel". In the other position
it says "This data is the right channel" there are always two channels.
Unlike S/PDIF there are no subcodes. It is simply raw serial audio data. The
point is that it works exceedingly well and it would otherwise cost you
about 3 or 4 times as much to make a more discrete, parallel codec system.
Thus everybody uses it these days.

Ok with that as background you can see that having a single stereo pair,
analogue output from one of these boxes would simply require one I2S stream
which could be easily derived from *say* a Motorola DSP56K. Which has a
bidirectional I2S interface onboard as standard.

But lets assume that the system is a little more discrete than that. You
would have a chip designed to convert parallel audio data into I2S so that
it can talk to the D-A converter. In order to add more outputs you would
need to add more of these chips and more D-A converters. In order to make it
recognize the new I2S stream(s) you would need to first, add the necessary
glue logic and then re-code the software so that it could separate the
channels to the new audio streams. One pair at time. Remember there are
always 2 channels.

You would either need the original source code or sit down and hand un-pick
the code yourself. It's possible but unless you have an IQ of about a
million and a few months of your life to expend on the task, it would be
extremely difficult.

Now I'm not saying it can't be done. If you were a retro-fit company and you
saw a golden opportunity in the market you might consider paying someone to
reverse engineer it. What would a top software engineer get paid a month
these days? But other than that I'd revert to the short answer and say "NO".

Hope that helps.

Be absolutely ICebox.
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