pitch voltage in VM

[seal58]

Sorry for asking this again: What is the pitch voltage area in VM. I'm not sure, was it -3 to +5 ?
(-3.0 volts for C0?)

Explanation of "Technical Specifications" in VMD manual does not refer to this theme.
It was discussed in this forum. Unfortunately it is not possible to search for "pitch" or "voltage". So I cannot recover that topic.

[ColinP]

This might be the thread you were after....

viewtopic.php?f=8&t=2001&p=8296&hilit=organ+feet#p8296

There's no real agreement about standards (or apparently even the laws of physics) but 0 V = C2 seems to be the consensus.

So you can use 65.40639 * Math.pow( 2.0, controlVoltage) to convert pitch CV to frequency in Hz.

Note there's no voltage limit in VM just a convention that the nominal range is -5 to +5 volts.

Although as time is represented by one volt per bar in LSSP rather than being clock based I routinely use "voltages" approaching 100 V and I haven't managed to set anything on fire yet.

[seal58]

Thank you Colin,

that was one of the topics, I meant. Another one discussed the relationship between pitch, MIDI note and VM voltage.

Until now I mostly used 0 to 10 volts for my VMD projects, what was a widely used standard for hardware modules and basically is similar for MIDI notes from 0 to 127. But I know, there are/were some systems with a 10 volts per octave system. There you also work with voltages until 100 V.

Because of difference to VM specification I think of adding switches to some of my modules.

Roland

[UrbanCyborg]

Roland, C0 is -2.0V. I believe your CV Meter is off by one volt, assuming you mean to match CA's voltage/pitch scheme, with A4 = 440Hz = 2.75V. If I'm missing something, I'll apologize in advance.

[seal58]

Thank you, that's a good hint.

ColinP already mentioned

"There's no real agreement about standards (or apparently even the laws of physics) but 0 V = C2 seems to be the consensus."

Unfortunately There's no real agreement about standards within VM until now. But it should! We developers need basic rules. If everybody uses it's own "standard", real modularity will not be available.

Changing CV Meter is not a big deal. I will do that soon.

Roland

[ColinP]

My vote is definitely for 0 V = C2 (the same thing as C0 = -2 V).

But as long as the reference is C then being an octave out isn't going to cause too many problems. Things will still be in tune even when in the wrong octave.

Unfortunately some people seem to think that A should be the reference (probably because of the A4 = 440 Hz tuning standard) but this is not at all a good idea!

[UrbanCyborg]

Okay, I'll bite. Why is it not a good idea?

[ColinP]

Using A?

Because most systems use C so if you add a component that uses A as the reference instead of a unison sound you'll end up with a minor third interval (or a major sixth depending on the octave perspective).

That might be musically interesting but very confusing/undesirable if unexpected.

Also in musical notation C is what a programmer would call the index origin.

[UrbanCyborg]

I assume that by "most systems" you mean most rack systems. In the system of Western music, A is the reference, no matter what the native key of the instrument. But it really doesn't matter for a rack system, anyway, so long as you're careful to set the voltage that represents A440 (or any other pitch standard) to a value that results in C2 = 0V, which A440 = 2.75V does.

I think we're really on the same page here. I think it does make a difference if a meter reports a different value than VM's system dictates.

Reid

[ColinP]

Yup, I think we are on the same page.

It's just that I guess the word reference has two meanings. One as a relationship between note name and frequency as in A4 = 440 Hz and the other between CV and note name as in 0 V = C2.

So A4 = 440 Hz and 0 V = C2 are totally compatible. All I was saying was that something like 0 V = A2 was a bad idea.

Is there something in the VM documentation that dictates 0 V = C2? I've not come across that but would welcome such a declaration from CA.