Poly-Mod and Sync Tutorial

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edautana
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Joined: Sun Dec 24, 2006 12:05 am

Poly-Mod and Sync Tutorial

Post by edautana » Thu Dec 28, 2006 8:51 am

Hi everyone!

Do you know about a good Poly-Mod and Sync Tutorial???

I want to go in deep with these functions.

I have various books related with subtractive analog programming and the Prophet 5 rev 3 manual, but they just talk about them in a general way (specially Poly-Mod section).

I was researching in the Internet but the same; everything is general topics.

Thank you for the advice.
"99% work, 1% inspiration" A. Einstein

Le Bone
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Joined: Thu Aug 10, 2006 4:00 pm
Location: Wakefield, Yorkshire, England

Post by Le Bone » Thu Dec 28, 2006 12:08 pm

computer music had some articles on basic synthesis methods including subtractive synthesis which covered these concepts. articles available for download on computermusic.co.uk as pdf's.

you need to understand the basic buildings blocks of this type of synthesis. it's alot easier than it may seem at first. the intersesting parts are the different ways of modulating oscillaters and/or filters to give a sound some sort of variance as it sounds. thats where polymod comes in and allows different gubbins to affect the oscillator/filter/volume.

the original odyssey manual explains these quite well as does the novation kstation manual (novationmusic.com). you can download these from the appropriate websites.

edautana
Posts: 10
Joined: Sun Dec 24, 2006 12:05 am

Post by edautana » Thu Dec 28, 2006 12:49 pm

Hi Le Bone:

Thank you for the info. I was researching in Computer Music last week, but I couldn’t read anything about Poly-Mod. I just found some general info about sync oscillators. Maybe I overlook something, I’ll check again.

The first analog synth that I own since 20 years ago or so, was the Roland SH3-A, a very rare mono and simple synth. It is very fat (1 oscillator and 6 sub oscillators). I have it here with me, but I don’t use it too often, it has some problems (the keys are sticky and delayed). With it, I learned the basic building blocks of analog synthesis (it hasn’t poly-mod or sync oscillation).

I was buying analog things during the last years, eg. a korg poly 800mkII (it sounded great, but the osc became out of tune with time and it couldn't be fix), the last approach was a Yamaha AN1x analog physical modeling, it's great (incredible pads), I use it a lot, but it doesn't have the fatness you expect from a real analog; I played some soft synth too.
Now my ears tell me that the Pro-12 has the sound that I always wanted to hear (it reminds me the time with the SH3-A). I must say that Prophet 5 was always the synth of my dreams.

Any way, I was experimenting with the Poly-Mod section and it’s OK, but I feel that I need some technical guidelines, specifically in that topic.

Perhaps somebody wrote a tutorial about poly-mod.

If I find a tutorial, I’ll let the ASB community know about it by posting it.

Thanks Le Bone for the help, I’ll be hanging around in the forum.

Best regards
"99% work, 1% inspiration" A. Einstein

edautana
Posts: 10
Joined: Sun Dec 24, 2006 12:05 am

Post by edautana » Fri Dec 29, 2006 8:40 pm

Hi there!

Le Bon, you were right, I overlooked something.

In soundonsound tutorials (section SYNTH SECRETS) they talk about
POLY-MOD usually as frequency modulation (not digital FM as DX7),. I have to say that there is no an specific tutorial about “analog frequency modulation” instead I have to read and dig a little bit in the articles related to the kind of basic sounds that usually are developed with the analog frequency modulation function (eg. snare drums)

For the forum the link of the articles:

http://www.soundonsound.com/sos/Aug01/a ... rets28.asp

Remember you have to dig inside the articles to find what you are looking for. There are many topics related to analog synth aside analog frequency modulation.

As you suggested the manuals of the odyssey and other analog synths have some info about the topic.
"99% work, 1% inspiration" A. Einstein

johnbowen
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Post by johnbowen » Sat Jan 20, 2007 11:49 pm

Hi,
Poly Mod is my terminology. I made up the phrase to stand for "Polyphonic Modulation" when I designed it for the Prophet 5 - the idea being that the single LFO that affected all oscillators the same was "monophonic modulation", but routing the output of Osc B and the Filter Envelope as mod sources for each voice gave separate modulations for each voice independently (so, for example, Osc B running as an LFO would have these out of phase modulation results), which I named "Polyphonic Modulation" or Poly Mod for short.

The main idea is that when using Osc B as a mod source, you get these separate and individual modulation results, and with the Envelopes, you don't get retriggering of all the voices every time you play a new voice (only enveloping of the one voice played), which is what you would get if you had a 'monophonic' envelope source.

Cheers,
John Bowen

Le Bone
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Location: Wakefield, Yorkshire, England

Post by Le Bone » Mon Jan 22, 2007 4:30 am

Wow, straight from the horses mouth (as we say in the UK).

Standard Analogue Synth Modulation but in a polyphonic way! Which is the opposite of my two Korg Mono/Poly's which have "Mono Modulation".

edautana
Posts: 10
Joined: Sun Dec 24, 2006 12:05 am

Thank you Mr. Bowen

Post by edautana » Sun Jan 28, 2007 6:37 pm

Dear Mr. Bowen:

Thank you very much to illuminate us in this topic!.

To read about “Poly Mod” from the “Father” of the “Poly Mod” is incredible, Wow!. Really, thank you!,.

I’m going to try some experiments with the poly-mod this week.

If I understood, I’ll try to generate a sound with LFO Osc b triangle wave, in order to generate phase differences in the sound due the delay of key pressing time in a chord.

The other part that I found very interesting about Poly-Mod is the use of the Osc b in non-LFO mode (a more difficult topic in my opinion).

I read some articles and books out there about it, but the info is very vague or in the other hand too technical (frequency modulation). There is no practical information “in-between” with easy guidelines.

Yes I know the answer:…. I have to tweak the knobs and experiment!.
But maybe there is some useful info somewhere.

Hoping to learn more from your comments.

Best Regards
"99% work, 1% inspiration" A. Einstein

johnbowen
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Joined: Wed Mar 19, 2003 4:00 pm
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Post by johnbowen » Thu Feb 01, 2007 8:47 am

Yes, for me the primary interest was to provide audio rate modulation of the filter cutoff frequency with Osc B. As it turns out, modulating the pulse width at audio rates causes some interesting results as well, and of course, exponential frequency modulation of Osc A by Osc B (what some synths call 'cross-modulation') will give you an extended range of timbres to work with.

But I've found that, when explaining the concept of Poly Mod, if I use Osc B at slower frequencies first, it helps illustrate the Poly Mod idea more easily. When modulating at audio rates, I would suggest first trying basic harmonic intervals such as octaves and fifths, using the Osc B Fine tune to adjust any small offsets (especially when modulating the filter cutoff). I like to start by having the filter self-oscillate by putting the Resonance all the way up (or nearly), and tuning the cutoff to a specific pitch, then adjusting the tuning and Poly Mod amount from Osc B to the filter in the Poly Mod section to get a start on the sound. Then back off the Resonance if you want a less 'drastic' effect.

Cross-modulation for me was the least used, because it's very hard to get things to work across the keyboard range in a way I like, but it certainly can provide you with some unusual timbres as well.

Hope this helps,
cheers,
John B.

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