Is modulating >1 signal source a qualitatively different beast?

[Mark Hammer]

Just came back from coffee, and the place downstairs from work had some "classic rock" satellite station on.  As I sat sipping and reading, The Eagles "Life in the Fast Lane" came on.  At the start of the outro and end solos, there is some through-zero flanging used to heighten the drama of the tune.  I've often mentioned here that effects like flanging and phasing are more perceptibly pronounced when they are applied to greater bandwidth.  So, if you want to sell a flanger or phaser, or other type of filter, your best illustration should use a white or pink noise source.  Alternatively, if several signal sources are mixed down to mono and the flanging/phasing is applied to that, you also get a more dramatic effect.

But listening to the tune made me realize that it's not JUST the greater spectral coverage that increases the seeming impact of the effect.  Rather, it is the manner in which the effect imposes correlation on two or more largely uncorrelated signal sources.  In other words, If I'm playing acoustic guitar, and you're playing drums, what comes out of each of our instruments (well, mic signals, to be more precise) is different.  We're playing the same tune, of course, but maybe handling the beat differently, emphasizing different aspects, etc.  When we are both processed simultaneously through a flanger (and whether it is through zero or not is immaterial), the same thing is happening to us both at the same time, even though we are different.  It is an unconscious cognitive/perceptual struggle to sort that out.  I suspect it is that same-or-different-? challenge to the ear/brain which makes the effect all the more interesting and dramatic.  It's almost the same perceptual confusion that happens when you're seated on a train at a train station, looking oyut the window, and for an instant you're not sure if it's your train that has started moving, or the other one you're looking at.

I don't think it is necessarily restricted to filtering effects like flanging and phasing, either.  IIRC, the old Tommy James tune "Crimson and Clover" applies tremolo to the whole mix at a certain point, and it's a lot more interesting than standard tremolo on a guitar.

Maybe we ought to start building in secondary input jacks and mixing capability into some of our pedals. 

[PRR]

> I suspect it is that same-or-different-? challenge to the ear/brain which makes the effect all the more interesting and dramatic.

Naked in the woods. You hear a tiger on the left, a bear on the right. But then you hear them walking IN-STEP. Yes, I bet that's "more interesting and dramatic".

> "Crimson and Clover" applies tremolo to the whole mix

Whole, or just Voice? Tremolated voice was novel (discounting the by-then-unfashionable yodelers, like Jimmy Rodgers, who moreover synced the wobble to the song, not async like singing through a Vibro-Verb).

[PRR]

The song contains a tremolo effect on the guitar, set so that it vibrated in time with the song's rhythm. Near the end of the recording, the band had an idea of utilizing the tremolo effect with vocals. To achieve this, the voice microphone was plugged into an Ampeg guitar amplifier with tremolo turned on, and the output from the amplifier was recorded while James sang "Crimson and clover, over and over".

http://en.wikipedia.org/wiki/Crimson_and_Clover#Composition_and_recording

[gritz]

I think that correlation is a pretty expressive and intuitive way of describing it (although it's possibly ripe for heckling from pedant's corner!).

A similar situation from here in electronica-land: Very often an entire drum submix will be fed thru the same compressor to glue it all together and make it sound like a living, breathing monolithic source, rather than disparate bits and bobs - I use the word "drum" in it's widest context as I'm likely talking about twips, whooshes and thuds from tortured samples and synths, although there may be real acoustic percussion hits in there too...

Similarly, an adopted "family" of sounds that were originally born miles apart may be put in the same space with a send to a shared reverb, or given fairly extreme common EQ colouring,. Funnily enough, modulation (in the sense of phase, flange and chorus) in electronica *tends* not to be applied to sounds in unison, but tends to be a modifier for a single voice. Modulation of an entire mix, or part of that mix tends to be in the form of "apply filter and waggle Cutoff and Resonance knobs to taste". It's the same correlation thing though, I suppose. And it does make the listener feel - albeit briefly - that what they're listening to is an artifice, or a warped version of reality - rather than a performance per se.

But that's getting a bit arty and out of my comfort zone!

[drolo]

Naked in the woods. You hear a tiger on the left, a bear on the right. But then you hear them walking IN-STEP. Yes, I bet that's "more interesting and dramatic".

Why naked ?? :-D

[Digital Larry]

Think it's the end of Pink Floyd's "Have a Cigar" where it sounds like the band fell down an elevator shaft... certainly gets your attention.

[R.G.]

Why naked ?? :-D

Why not? 

[drolo]

Why naked ?? :-D

Why not? 

true ...

Having breakfast naked definitely felt "more interesting and dramatic" after I adopted my wife's 2 cats when we started living together ...

[R.G.]

To answer Mark's question, yes, modifying more than one signal source simultaneously is qualitatively different.

Instead of putting two inputs on an effect, I'd go the systems way and come up with a separate LFO module and input specs so that I could externally modulate an effect from the LFO module.

I think it would be interesting to modulate both different signal sources from the same LFO, as well as doing synchronized modulation of say, flanger and tremolo by the same LFO on the same instrument.

All of this stuff we do to audio signals amounts to using signal changing to push the inbuilt buttons of the human hearing apparatus. Synchronism is certainly underused.