KNOBZ.NET - Sound Design and Modular Synth Improv/Tutorials

[PHC]

Hi

Stay tuned as my Sound Design and Modular Synth Improv and Tutorials is almost ready.

VISIT: KNOBZ.NET

[griffin avid]

Why couldn't you wait till the website had something on it before telling us?

[PHC]

The site is up!

http://KNOBZ.NET

Enjoy

[Tsarik]

cool website and great idea. i'll be watching

[Juno6]

"Cross modulation is a technique where two (or more) sources modulate each other."

This is not true. Cross modulation doesn´t have to be bidirectional.

[PHC]

Hmmm. Everywhere I encountered the term crossmodulation in a synth situation, the "bidirectional" thing was the thing that made the modulation "cross", but please explain. I took the concept from Richard Lainhart's Tutorial on MacProVideo.

[Juno6]

Just to give you an example, take a look at a Jupiter-6 panel...

http://www.thesmith.org.uk/music/studio ... CF+ENV.jpg

Cross modulation simply is oscillator 2 modulating oscillator 1. There`s no bidirectional
modulation. So, I agree with you that it´s not a correct name for it, but I hardly ever
found any poly that has bidirectional modulation (except A6 maybe), most of the time
is one osc modulating another osc. That is cross modulation.

[sqweebking]

Pretty awesome Moog rig you got there.

[PHC]

That is just audio rate modulation of one osc by the other. I see no reason to call it cross. I believe that they used this name (not very preciselly) because they followed the logic of the radio world, when cross modulation means that the carrier is being modulated by an undesired frequency.

Usually an osc is modulated by an external source (like an LFO) at that is a "desired" (usual) situation. The situation of one audio osc modulating the other is less common, so they used the term cross modulation to emphasize that on that synth panel. But's as I said before that's only Audio Rate FM osc2->osc1 (For the sake of this argument, what do You believe is the difference between Audio Rate FM and Cross Modulation?).

I know that the radio and synth world should follow the same signal theory laws and definitions, but the definition of "cross" meaning "bidirectional" suits my sense of logic and I've seen that name used before in a synth situation for bidirectional FM and I intend to leave it that way, (even if some "synth theory purists" might disagree) because it gives a good name of what's happening in that patch.

Thanx for Your insight Juno6, feel free to discuss any tutorials I post.

sqweebking: Thanx

[Juno6]

But's as I said before that's only Audio Rate FM osc2->osc1 (For the sake of this argument, what do You believe is the difference between Audio Rate FM and Cross Modulation?).

No difference between audio rate fm and cross mod. Different names for the same thing.

but the definition of "cross" meaning "bidirectional" suits my sense of logic and I've seen that name used before in a synth situation for bidirectional FM and I intend to leave it that way,

Of the several meanings of the word "Cross", this is the one that suits better to me:

Cross 27
Definition: To move or pass from one side to the other, or from place to place; to make a transit.

In that sense it doesn´t mean bidirectional.
You simply won´t find a knob that´s called "Cross Modulation" that´ll make two oscillators modulate each other. I´ve never ever seen something like that in my life.

Cheers.

[Stab Frenzy]

I always thought that cross mod was another name for frequency modulation, like how ring mod is for amplitude modulation. Could be wrong though.

[smoothcriminal]

You simply won´t find a knob that´s called "Cross Modulation" that´ll make two oscillators modulate each other. I´ve never ever seen something like that in my life. Cheers.

I think your post is spot on, but my MicroQ can use 2 oscs as FM sources for each other. It's not a "knob" but still. The only synth I've ever owned with an Xmod knob was a Korg EA-1, and like you say, using osc1 as an FM source for osc2 (on the Micro) sounds more like that effect than the bidirectional FM.

[PHC]

Stab Frenzy: Ring Modulation is a specific type of amplitude modulation, because the base frequencies are not present at the output. It's actually AM with supressed carrier. So every RingMod is AM, but not every AM is RingMod.

Juno6: But I still don't agree that AudioFM is CrossMod every time, because if You'd have:
osc1 modulating osc2 amplitude (via a VCA)
osc2 modulating osc1 waveshape
it would be crossmod and would leave FM out of the equation.

I've done some research and X-mod is something Roland uses in it's synths and it describes what Juno6 saiz.
Maybe I won't find a knob for bi-dir x-mod, since You'd need two knobs since there are 2 modulation indexes if You'd like to go both ways But in a modular enviromnent I'd still think that it's a proper name (maybe it doesn't exhaust the topic, but the name is not a mistake, because as Juno6 said it's not always bi-dir, but in my example it is). If You insist, I can add a sentence that in my example it is bidirectional and everybody will be satisfied.

[PHC]

New tutorial in the Synthz section
http://knobz.net/synth4.html

[Automatic Gainsay]

I always assumed "cross mod" was more than just one oscillator modulating another... especially because that is essentially what happens any time LFO is used, and we already have a name for that. "LFO." Granted, it seems to refer to audio-frequency-level modulation... but still, that is just frequency modulation... something we already had a name for even before portable synthesizers existed. It's just an example of manufacturers coming up with a function name that sounds cool and achieves its purpose.
Simply because "cross modulation" seems to be a half-assed way of saying "one osc modulating another" does not necessarily mean that two oscillators modulating each other is NOT "cross mod."