CV to Hertz module?

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honki-bobo
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Re: CV to Hertz module?

Post by honki-bobo » Wed May 27, 2020 5:33 am

andro wrote:
Wed May 27, 2020 1:41 am
@honki-bobo, having myself just written a volt meter, I am surprised to see yours. I can't find it on the store. That's worth releasing (in competition with my upcoming one).
I haven't released that one yet. And it is going to be free, since it doesn't really do anything :)
andro wrote:
Wed May 27, 2020 4:59 am
So I end up with y = 65.406398*2^x whereas you have the vastly more elegant y = 55*2^(x + 0.25). The 0.25 is of course the negative voltage offset at 55 Hz based on A440, the voltage for 55Hz being -0.25V.

Hat off to you. Sometimes I wonder why I am so dumb! Did you derive that yourself or is it well known and I am just ignorant of basic things?
You are far from dumb, my friend. Your formula is absolutely correct, as 0V maps to C2, which is 65.40639... Hz (at a 440 Hz A4). Since frequency doubles every octave (2^1, this is why 1V/oct works so well) and we have 12 tone equal temperament (at least in western music) the distance between two half tones is 2^(1/12). Now since 65.40639... is actually an irrational number and will never be exact, no matter how many decimal places you enter, I simply shifted the exponent by 3 halftones, ergo 3/12 = 1/4 = 0.25, as you have correctly stated.
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andro
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Re: CV to Hertz module?

Post by andro » Wed May 27, 2020 7:08 am

Coming soon to a store near you.

frequency-meter.jpg
frequency-meter.jpg (82.13 KiB) Viewed 733 times

Middle C! Would there be any need for more than three inputs? Is three excessive anyway?

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honki-bobo
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Re: CV to Hertz module?

Post by honki-bobo » Wed May 27, 2020 7:41 am

andro wrote:
Wed May 27, 2020 7:08 am
Would there be any need for more than three inputs? Is three excessive anyway?
That is a design decision that is up to you :)

Ask yourself: "If I couldn't implement this myself and would need to use a third party module for this, what would I expect from such a module?"
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andro
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Re: CV to Hertz module?

Post by andro » Wed May 27, 2020 8:25 am

A good way of looking at design. Thanks! Yes, as programmers it is easy to come up with answers to problems people do not have.

sdv
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Re: CV to Hertz module?

Post by sdv » Wed May 27, 2020 7:18 pm

andro wrote:
Wed May 27, 2020 7:08 am
Middle C! Would there be any need for more than three inputs? Is three excessive anyway?
I was hoping for at least six inputs as I'm planning on creating my own scales.
Come to think of it why not make it eight. :D
And, what would even be more helpful is a pass-through jack for each input to the right of the readout meter.

MRBarton
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Joined: Sat Aug 10, 2019 7:11 pm

Re: CV to Hertz module?

Post by MRBarton » Wed May 27, 2020 8:48 pm

Looks like a useful tool. However, the label above the readouts is confusing. Does it mean Hz OR Volts, or Hz per Volt which is just wrong. If the former, how about changing the text label on the fly from Hz to V depending on the switch setting. Or better still, since readouts are free in software, put both on everything. Excess is best.

--mb

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