I think the point of the scale quantizer is the ability to confine the
output voltages of a Sample Hold to specific voltages deemed to be musically
useful, such as a major or minor scale.
I think a chromatic scale makes some sense as the intervals are equal. You
would be quantizing to the nearest 1/12 volt. Major or minor scales are
more problematic as the intervals are not equal. If the inputs to the scale
quantizer are truly random and the interals of the quantizer are not equal
some note would play more than others since the probability of the random
voltage input falling into a samller interval is less than falling into a
greater one.
Some feel that to be musical, sounds have to be confined to equally tempered
or other scales. Others feel that this is confining. I personally think
both approaches are musically useful and valid.
I would rather see a quantizer as a seperate module.
Also responding to Tony at Oakley ---
I had not thought about the lack of precision in the rectifiers affecting
the timing between pulses, thanks for pointing that out.
You are certainly correct about the noise level increasing with each stage.
I have played around with this on a breadboard and gone 32x without too much
difficulty, but had not considered what amounts to clock jitter. Obviously
to maintain high factors of multiplication at increasing frequencies you
would need op amps with high bandwidth product.
Paul H.
----- Original Message -----
From: "jfm3" <jfm3@...>
To: "mate_stubb" <mate_stubb@...>
Cc: <motm@yahoogroups.com>
Sent: Monday, January 02, 2006 1:28 PM
Subject: Re: [motm] Re: Interest in a MOTM-102 module?
> I've generated some confusion and remain confused myself, so I'll try to
> undo that...
>
> Paul H. replied to ach_gott@...:
>> No, I'm not looking for a sequencer.
>
> Paul H, I don't think he was talking to you, he was correcting me. I
> think the point at which I became confused (and remain confused) is when
> Richard Brewster wrote:
>
>> This may be asking for a lot, but could it have a scale quantizer?
>> It
>> is digital to begin with. How much extra would adding a major/minor
>> scale be? How about a 3-position toggle switch: major/minor/off.
>
> Really, all I wanted to add to the conversation was that I thought
> major/minor/off was too limiting. I probably wouldn't use it, at
> least.
>
> What follows is more of what I've figured out so far, you should only
> read it if you're feeling charitable :)
>
> I think that a "scale quantizer" here is: 1) CV meant to represent a
> pitch comes in, then 2) nearest allowable pitch CV comes out, where
> allowable pitches are selected from a ROM table, or something. I'm not
> even sure what this has to do with a S&H, other than perhaps that the
> circuitry for the S&H may be easily extended to provide this "scale
> quantizer" functionality (perhaps because there is a digital section
> which can be programmed more or less arbitrarily?).
>
> I do want some way to take a CV meant to represent a pitch and feed it
> to a machine which produces one of N CVs, each decided upon by a knob.
> It turns out this is what I'm terming a "VC sequencer" -- my jargon may
> be off. At this point I'll resort to cheap math to display my ignorance
> of electronics :) Imagine the incoming CV as a real value in [0 1].
> Normally, this is interpreted by a VCO as a pitch. A four step "VC
> sequencer" would act like a function:
>
> f(x) = a if x < .25
> b if x >= .25 and x < .50
> c if x >= .50 and x < .75
> d if x >= .75
>
> a, b, c, and d, are controllable with knobs. Now if the real values of
> a, b, c, and d, were the notes in a maj7 chord, we'd have something like
> a "scale quantizer". If instead x is a value that changes over time,
> such as a saw tooth wave which rises from 0 to 1 every 4 seconds, then
> we have a sequencer. Of course an ideal sequencer would have more
> possible values, and other features, I'm just trying to get the model in
> my head correctly.
>
> It seems like the miniwave is like the function above except there are
> 256 possible function values (a, b, c, d, e, f, ...), that these values
> are relatively low resolution, preset in a ROM, and not as accurate
> ("droopy") as some would like for the purposes of CVs that represent
> pitches.
>
> How am I doing?
>
> If I've got it right so far, then I'd say having a scale quantizer in my
> S&H module was ... strange.
>
> On Mon, 2006-01-02 at 17:08 +0000, mate_stubb wrote:
>> > What's the output CV resolution on the Miniwave, and can you still
>> > get them?
>>
>> A Miniwave is an 8 bit ROM addressable via voltage control. There are
>> 16 banks of 16 wavetables, and each wavetable is I think 256 bytes
>> long. You choose which of the 256 memory locations in a table is
>> connected to the output via a DAC by the input control voltage.
>>
>> So this device has an 8 bit output resolution, and also has no droop
>> problems. Scanning the tables via various waveforms (saw, tri, reverse
>> saw) allows you to control the direction of playback as you mentioned.
>>
>> Hope this helps clear things up!
>
> This very much helps to clear things up. Thank you very much!
> --
> (jfm3)
>
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