MOTM

In a message dated 4/13/2000 1:52:40 PM, ken.tkacs@... writes:

 #1. > At position
>1,
>there is no bias, so VCO #2 > is at unison with VCO #1. Switching to
>position #2 would put VCO#2 up one > octave (the first harmonic). The next
>position is octave-fifth (2nd > harmonic), then 2-octaves, 2-octaves-third,
>two-octaves-fifth.... etc, up to > as many harmonics as you have switch
>positions and trim pots for.

I like Moe's idea of the Emu type soft sync -- is the CEM 3340 soft sync of 
similar hardness as that?


>> This ability to easily dial in exact partials on secondary VCOs, to me,
>would be awesome. 

Me too!

>(> In fact, there is a little known property of acoustic physics called
>"sub-harmonics." I don't mean sub-octaves. But a sound can induce a larger
>object to resonate at frequencies LOWER than its fundamental by exciting
>a >
>higher harmonic of the resonant properties of the second object. It is
>very
>> subtle. Henry Cowell wrote about this in his book "New Musical Resources"
>back in 1911. I think Walter Piston even addresses it in one of is famous
>books on harmony and/or orchestration. The first sub-harmonic of C is a
>lower F. 

I definitely need to look into this! Keep these references coming Ken! I 
guess it's not the same thing (though I did think it was until reading your 
post) but I have a VC Dividing Comparator (from another mfg.) which (amongst 
other uses) will divide a waveform by any integer from 1 to 32 under VC. The 
MOTM 120, of course, only does successive divisions by two, so these modules 
aren't doing the same thing. Note that when you divide a C, for example, by 
three you get a (just intonation) F an octave and a fourth below. So you get 
the "subharmonic series" with the larger number divisors being quite close 
together -- there is a rumor that a similar MOTM module "may or may not" be 
on the way. But I didn't tell you that!


The sounding board of a > piano actually adds these sub-harmonics
>in VERY subtle amounts. It would be > neat to be able to play with these
>easily.

Absolutely!

>> Now, to make this *more* of a nightmare project...

Gulp!

A CV could change the quantized
>> biasing as well as the front panel control. What could you do with this?
>You could have a CV, like an LFO, force a VCO to > sweep the harmonic
>series! This is an effect people try to get with Serge > waveshapers,

Not to be to didactic, BUT, I think you're talking about the Wave Multipliers 
module -- which "adds harmonic content." The Triple Waveshaper is aptly named 
since it does a "harmonic reduction <joke>" and can turn a saw into a sine 
under certain conditions. The Wave Multipliers is the more magical of the two 
by far.

 This is similar to what happens in nature
>with
>pitched percussive instruments, but can be just different enough to be
>really wild.


I still think that some interesting work with gating FM with simple waveforms 
and synching involving several VCOs could produce some worthwhile results in 
this respect.

>This to me is a VERY exciting idea. With the second VCO producing a sine
>wave and the above effect being patched up, I can only imagine that it
>would
>sound like the first VCO's signal was being split and the side-chain was
>going through an impossibly tight bandpass filter that only emphasized
>one
>single harmonic at a time. 



>(Wendy Carlos comments on "Secrets of Synthesis" that analog tends to
>deteriorate "into that quasi-organ sound that most synthesizer work
>eventually degenerates into." That's because most people tune square waves
>to simple octaves and fifths to build a sound, which does start to sound
>the
>same after a while. This need not be the case, and this module works
>*against* that organ-ish tendency.)


Good point!

>> I can imagine a 2u module. The four pots on the left side set the harmonic
>> offsets for four VCOs. The four pots on the right are attenuators for
>the
>incoming CVs to modulate them. Four > jacks are CV ins, and 4 are the biased
>outs.



>Okay, next.
>
>The weak link is the bank of trim pots, one per harmonic relationship.
>Now,
>I know NOTHING about > PIC processors, but I'm told they are cheap and
>really useful. I'm wondering > if the DACs in these are good enough so
>that
>the harmonic relationships > could be programmed into a PIC chip. That
>way
>they can be exactly specified > and theoretically would not drift. 


>As the above idea evolved, it resembled less of the original octave switch
>and more of a really unique, specific kind of quantizer. Maybe this function
>can work its way into any quantizer designs that might be on the drawing
>board out there. As a stand-alone module, it might be esoteric, but if
>this
>could be a feature of another module, it would be more economical. It would
>be neat if there was some kind of switch: in one position, it quantizes
>in
>1/12 volt steps, like you would *expect* a quantizer to, and in other switch
>positions, an effect like the above could be implemented. Because really,
>what I'm describing is a quantizer for Just-Intoned tuning, if used that
>way, which is an important compliment to equal-tempered tuning. If the
>module were _uP_ based, I would think this would be a low-part
>implementation. Just a little extra programming and a switch. (Am I
>wrong...?)


As Bradley said, the quantizer has been brought up before. I think Thomas H. 
proposed the term "personalities" which could be loaded in to the quatizer 
which could generate specific keys, temperaments, microtunings, scales, 
chords, etc., to allow for a variety different uses. I'd think it would be 
easier to allow for such change information to be loaded via MIDI than CV.


I'm pretty sure the old Serge quantizer uses a simple bit masking system in 
order to allow for gate control of the different quantizing intervals (I 
think one input going high quantizes to a whole tone scale and the other to a 
dim7 -- successive minor thirds -- if they are both high, the output will be 
a diminished scale, i.e., whole step - half step - whole step - ... -- a 
combination of the two). To have a just intonation, equal temperament, 
quarter tone, micro tone, Phrygian mode, etc., quantizer (like I'd love to 
have!) seems like it would be much more difficult -- of course maybe these 
could be just software upgrades.


>I'm raving about this out loud because I'm not an engineer, and can't
>implement this nut-bag idea on my own, otherwise I would just build it
>and
>demonstrate it. I understand acoustic physics a hell of a lot better than
>I
>understand the nitty-gritty of the electronics. I just wanted to see if
>there was anyone out there who thinks this could be as cool as I do. Can
>I
>get anyone to chant along with me...?


Very definitely! I'm in the same position, so keep on ranting!

>As you can tell, I don't use my modular just to do two-VCO leads over guitar
>pads... I'm trying to use it to create worlds.... I have weird needs...
>:) 

Me? I just use my modular to make pads, and play guitar lead over them! Keep 
creating those worlds Ken! I really would like to be able to visit them!
JB