Ring Modulator vs. Envelope Follower

[Constance]

So, I've read descriptions of both "ring modulator" and "envelope follower." One could almost hear the question mark popping into existence above my head.

With YouTube, I was able to find examples of an electric piano being run through a Ring Mod, so I kind of understand what such a thing can do. I came across demos of an Envelope Follower, too, but those clips did not include sound samples withOUT the effect in use for comparison.

Is anyone able to describe to this bonehead what an Envelope Follower does compared to other effects processors?

[tekla]

I'm doing Yes/Asia in the next few days.  I'll ask them.  Doubt if they will know.

[Lisbeth]

Turns on the envelope follower at 0:16.
Moog Envelope Follower

Turns off the envelope follower at 0:58.
Percussive Envelope follower

Cycling through chorus, phase and envelope follower.
Cycling thru chorus, phase and envelope follower

[Ani]

An envelope follower by itself does not generate a sound or modify one either.  It generates a signal that is used to modify the signal path in some way.  The most obvious example is an "Auto-Wah".  This is a Wah-Wah type sound, where the "wah" is not controlled by a foot pedal, but by how loud the person is playing.  The amplitude of the signal controls the wah's filter frequency.  Most common example is GratefulDead's "Estimated Prophet", or Edie Brickel's "What I Am" guitar solo.  Look for those on youtube.

That said, the control signal from the envelope follower could be used to control anything in an audio path.  Or for that matter, the brightness of a lamp.

http://www.viswiki.com/en/Auto-wah

[tekla]

Can you play?  ?? or is this all just science junk?

[Ani]

can i play?

what does that have to do with anything?

i've been playing keyboards since about 1965.

envelope followers have been around a long time.

do you know either of the tracks i mentioned?  the autowah on those tracks is completely distinctive - a signature for autowah

here's another not so commonly known use you might have heard of: ducking.  Ducking is automatically turning down the amplitude (volume) of one source using another source.  Why would tekla want to do this?  Say you were making a commercial or documentary, or whatever with a sound track and a narrator.  Ducking automatically turns down the background sound track when the narrator is speaking.  An envelope follower tracks the narrators voice, and turns down the background music inversely to how loud the narrator talks. this makes it easy to always hear the narrator.

if you like techno or disco music, another common use is to turn down everything just when the bass drum kicks.  this keeps the beat up front.  another way is to use the bass line to duck everything else.

this may be "science junk" to you but sometimes it pays to think

[Renate]

Science junk? Ok!

A ring modulator is more commonly known outside music as a double balanced mixer.
It is "double balanced" because of the rejection of either of the two inputs individually.
In the RF world it is implemented mostly as a "ring" of four diodes.
At lower frequencies an IC four quadrant multiplier does the job.
In the digital world, it's a trivial multiplication in the time domain.

As pointed out already by Ani, an envelope follower just extracts the average audio level as a control signal.

"Envelope follower" is used imprecisely to denote a setup involving that and some other building block.

My credentials for saying this: I play acoustic guitar without sound system or effects.

[Constance]

Yes and Asia? Are they still working? Wow.

An envelope follower by itself does not generate a sound or modify one either.  It generates a signal that is used to modify the signal path in some way.  The most obvious example is an "Auto-Wah".  This is a Wah-Wah type sound, where the "wah" is not controlled by a foot pedal, but by how loud the person is playing.  The amplitude of the signal controls the wah's filter frequency.  Most common example is GratefulDead's "Estimated Prophet", or Edie Brickel's "What I Am" guitar solo.  Look for those on youtube.

That said, the control signal from the envelope follower could be used to control anything in an audio path.  Or for that matter, the brightness of a lamp.

http://www.viswiki.com/en/Auto-wah

Thanks, ani, this is a very clear description.

[tekla]

Can't we just send a runner to Guitar Center for one?

And yes, Yes/Asia has embarked on huge tour of not so very big places.  Yes has Squire/Howe and White, with Wakeman's son on keys, and I don't know who being Jon Anderson, and it's all the original members of Asia.

>>>>> tekla, trying to figure out between misters Palmer and White how many drums that is.

can i play?
what does that have to do with anything?
I ask, because in my world sometimes it don't have anything to do with being in a band.