[OSC_dev] OSC replacement for MIDI

[Jeff Glatt]

>> MIDI note number 60 is supposed to produce a pitch at 261.63 Hertz.

> I'm not sure that's true

It's absolutely true. SQ (who came up with half the original spec) 
originally
underestimated the future for MIDI. I read an interview with Dave Smith 
where
he said he expected the only thing people would ever use MIDI for was to 
sync
two synths playing the exact same part in order to "thicken up" the sound
(because that's what customers were asking for more than any other feature
in the early 80's. They just wanted "a thicker synth sound").

Don't you know, if you send two synths a middle C note, and they don't
both play at 261.63 Hz then you've got a godawful unmusical noise. You
think SQ, Roland, and Yamaha wanted droves of musicians returning
Prophet 600s, D-110s, and DX-7s saying "My synth is broken. It doesn't
play in tune with that other synth."???

Nevermind the fact that _none_ of these instruments had _any_ facility to
do any other tuning than 12 tone equal-tempered western scale. Look up
the frequency for middle C in an equal-tempered scale. What is it? ....
There you go.

> I'm not sure as a statement it makes sense.

How can it _not_ make sense? Are you telling me that you would have
made a synth in 1984 that deliberately played out of tune with every other
synth being manufactured then???

> MIDI note event 60 doesn't say anything about frequency

Nope. It doesn't have to. It was designed to work with all of the synths 
being
manufactured at the time, and they all did equal-tempered 12 tone tuning, 
and
nothing but. (Well ok, maybe a fully loaded $200,000 Fairlight could perhaps
have been coaxed into some other scale with lots of "weird sample mapping".
But MIDI wasn't made for that).

Why do you think that MIDI says absolutely nothing about tuning, and in fact
never had a single message relating even slightly to a tuning system?.

Because all the synths were tuned exactly the same -- in a 12 tone equal 
tempered
scale. And that was all they sold. So there was no need to even think about 
tuning
issues. They didn't exist.

And BTW, why a MIDI note number? Because it fits in one 7-bit byte. None
of the MIDI messages except SysEx were supposed to be more than 3 bytes.
And you've already used up 2 of the bytes, of a note message, with the 
status
byte and the velocity. (They were so obsessed with minimizing the size of
messages, they even came up with a way to eliminate one of the bytes, 
referred
to as "running status").

> Any interesting tone will have large numbers of harmonics, many of
> which will be detuned, so we can only really talk about the
> "frequency" of a triggered note in terms of the fundamental or some
> main harmonic.

The "frequency" in my note-on message serves the purpose of telling a sound
generator at what frequency to run an oscillator, or at what speed to feed
digital audio samples to a DAC. Why are you continually talking about
acoustics and psycho-acoustics?? We're entirely in the electronic realm 
here.
There are no acoustics.

Ok what may be missing here is that there _is_ a presumed "reference
frequency". I've assumed it to be middle C at 261.63 Hertz. If you've got
some waveform recorded at 48KHz of a middle C note on a piano (ie,
261.63Hz), and you get a frequency of 261.63, obviously you're going to
play it at 48KHz. If you get a frequency of 277.18Hz, you're either going to
have to speed up the rate at which you feed samples to the DAC (by an
appropriate amount), or interpolate the original waveform so that it in
essense becomes a C# note (sampled at 48KHz) in an equal-tempered scale.
If you get a frequency of 272.54Hz, you're going to perform the same
operation with the result that your output becomes a C# note in just scale. 
It
doesn't matter if it actually is a sine wave playing at 272.54Hz, or a snare
drum. What matters isn't what the musician "perceives". What matters is the
amount of transposition the synth has actually done. It has nothing 
whatsoever
to do with acoustics.

This is the only why to do things where one entity can "control" the tuning 
of
all other entities transparently.

> When it comes to samplers and drum machines, there is
> no tonal semantics attached to the MIDI note numbers at all; they're
> just (velocity-sensitive) switches.

Forget about tone. That's psycho-acoustics. It's irrelevant here.