[music-dsp] Re: MIDI parameters

Paul Maddox P.Maddox at signal.qinetiq.com
Fri Feb 6 12:05:18 EST 2004


Martial,

> Sorry I use bad terms to ask my questions...

no problem, we all do from time to time.

> I know that MIDI does not send any musical sample, just messages. When I'm
> talking about a MIDI chip, I mean the sound chip synthesizer on sound
card,
> this is what I'm supposed to recreate, software.

ahh, right, I follow, you want to make a 'wavetable' (or FM) softsynth..

> I have to implement the
> digital filter, the LFO, the sample rate converter and everything inside
the
> chip on a DSP. This is a lot of job and if I can find a lot of information
> on the web on the MIDI messages and controller, there is poor
documentation
> on all the hardware needed to interpreter the messages correctly. Thus I
ask
> some non sense questions.

there's no such thing as a non sense question...
Ok, so you want to be able to control your 'sound synth' from MIDI?
What I think you will end up with is two processors,
one DSP, for your 'sound engine' and one hadling the MIDI data and
controlling the DSP.
For a list of MIDI messages take a look through the borg midi spec I
emailed.

> About the maximum pitch, this is because when you have a sample sound,
there
> is a limit to shift it. Maybe it's 3 or 4 octaves higher. But you can
create
> alisasing if the shift is to high, so this is why I 'm asking about the
> maximum pitch, all parameters combined...

:-)
That I dont think there is any hard and fast rule for, its practice.
For example, a piano will probably sound quite good when shifted up and down
2 octaves,
But a human voice will only sound good for a up and down around 5 or six
semitones.

> Just in case, I'm not an English person, I'm French and I'm sorry about
all
> the mistakes I can make in my post

don't worry, your english is FAR FAR better than my french!

Paul




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