Creative ducking - why a morphoduck?

[Mark Hammer]

Apologies to Chico Marx.

The threads on both the Controfuzz and the Flying Pan got me thinking....always a dangerous thing.

While ducking is normally used for other things, it can also be used for "morphing" like effects.

For the uninitiated, ducking and duckers are those things that radio announcers use to momentarily turn down the music while they talk over it.  Once they are finished talking, the music resumes normal broadcast volume.    In essence, a ducker is a bit like a noise gate with external keying, but in reverse.  In an externally keyed noise gate, the intended input signal does not reach the output unless there is another signal turning on the gate.  With a ducker, the audio input always reaches the output unaffected *unless* there is something else keying it "off".  UNlike noise gates, the keying signal itself is never actually heard (i.e., part of the audio output of the gate).  In the case of a ducker, it is.  

Ideally, duckers, like noise gates, will allow one to adjust how much reduction in the primary audio signal takes place; i.e., how low it "ducks".  It will also allow one to adjust decay or "transition" time, such that either you get a direct change or varying degrees of fading back and forth.

You can find an example of a ducking circuit (and explanation) here: http://www.paia.com/duckerda.htm   The Rolls company also has a document/manual for their Ducker posted at their corporate website, which includes the full schematic.

What I'd like to do with this thread is get people thnking about ducking circuits as essentially envelope-controlled mixers that can be adapted for morphing purposes.

The Controfuzz circuit that got me thinking about this, uses two versions of the same input signal.  Because one (straight) decays faster than the other (fuzz), when they are mixed together out of phase, you get an interesting transition as one gradually stops cancelling the other.  To a limited degree, this is an envelope-controlled transition, since striking the strings harder will necessarily result in a longer decay time for the straight signal.  However, because the transition is purely a matter of what frequency content these two parallel signal paths have in common, the transition is somewhat limited in scope.  I'd like to go beyond this and suggest that a full-spectrum transition, using ducking, could provide inexpensive and easily designed morphing.

Let's move to a concrete example.  Imagine you have a pedal where the input stage splits off in three directions: to an envelope detector, a swept filter, and a fuzz.  When the envelope signal is high, two things happen: the filter sweeps, and the fuzz is suppressed (although this could actually be reversed).  As the envelope signal declines/fades, the fuzz becomes unsuppressed and essentially "takes over" from the swept filter.  Voila, a simple morphing effect.  Build in enough performance controls to manage the transition artfully, and you could have a very usable unit.

Now that I think of it (and Ton, I know you're there.  I can see you. :wink: ), this could easily be a sort of nondedicated unit where you have an input, decent full-wave rectifier, an output, two effects loops, and assorted controls for managing loop balance, envelope sensitivity, and transition.  You could stick whatever you like in each loop.  You could sync a flanger and chorus to the same LFO but patch each effect into a different loop.  As you strum, the sound shifts from flanging to chorus (or vice versa).  The possibilities are endless.

So, what do you folks think?

[Arn C.]

Mark,
   I think it is a great idea!  It is always nice to be able to alter many different pedals' sounds without having to change each pedal, just a stand alone unit that you can use any of your pedals and experiment.  I hope more people get involved with this, looks like another winner!!!!

Peace and Thanks!!!
Arn C.

[moosapotamus]

Yeah! (didn't this come up once, way back when maybe?) The idea of having a nondedicated unit with two loops sounds wicked cool! Syncing two different modulation-type effects to the same LFO would require a dedicated unit, tho. Wouldn't it? But, anyway...

I really like the morph box idea. Might be able to generate some cool volume swell-type effects with the loop balance control, too.

Another cool feature to think about... Controlling the morphing envelope with a second input signal. Plug your instrument into one of the loop returns, and plug something else into the main input, like a drum machine, for example. You don't hear the drum machine. What you hear is the instrument signal going into the loop return getting morphed by the drum machine.

   

~ Charlie

[puretube]

Mark: I`m not supposed to tell secrets here in public, but guess what:

there are people busy with stuff similar to that...

:wink:

[puretube]

oh yes: R.G. had a nice article lately with the basic neccessary ingredients...

hint-wink-hint...

[Mark Hammer]

Ton,

Is this where I tell you to go duck yourself, or suggest that I don't know what the duck I'm talking about? :lol:

Without wishing to extract industry secrets, let me pose a question to you that you can field or decline:  For this sort of application, assuming you had a choice, what control element (FET, LDR, OTA, bipolar, etc.) would you prefer to use for ducking, and why?  My guess is that this sort of envelope control has special needs, but if you've experimented with it more than I have, you may have a better sense of what properties are desirable in such a situation.

I think it is worth pointing out that in the classic ducking situation, the two input signals (music and voice) are of a very different type than what you'd get with something like a guitar or bass input.  Bear in mind the music keeps going, and the voice can continue for as long as you want and also has short gaps in it (although my guess is that the rapid-fire style of many DJ's may well be a result of having to keep the ducking circuit continuously busy to prevent too much envelope ripple and flip-flop).  What this means is that one has the luxury of longer decay/transition times for a voice/music ducker, than one would for something where a unit transitions between two versions of a plucked string.  On the other hand, if the intention is to produce within-note transitions, the envelope follower doesn't need to be as complex or have as long a decay time as one where you want to smooth over the little gaps in 10 seconds of talking.

See, now if you could pack the "wet-panner" and this sort of morphing ducker into one general purpose pedal, you'd have a production tool that would be the stompbox equivalent of a "killer app".  I can't imagine a studio anywhere that would be content to be without one.  There ARE those little voice morpher things where you switch between robot-like vocoder voice and normal (remember Cher's big hit a few years ago?), but I gather that is all digital.  Having something where you could plug in whatever the heck you wanted (digital effect in Loop A, vintage pedal in Loop B) would be fabulous.

[puretube]

in short: OTA for the solidstate version (LM13700, CA3280),

or even better: an aphex, dbx, or THAT VCA-chip or two);

experimenting with NE57x at the moment...;

LDR for the Tube-Ducker;
(though I worked out a nice little tube-VCA a couple of years ago, which had over 80dB ctrl.-range....a little too complex for this kind of pedal)

[nelson]

Sorry to dig up an old thread. this thread is over a year old and I dont see any commercial examples.

I am wondering if its perhaps time we could investigate this further?

I mean, as usualy, Mark has a great idea.

Wish I had an idea of how to implement it.

[R.G.]

Wish I had an idea of how to implement it.

Applications of an audio Current Controlled Amplifier -  http://geofex.com/Article_Folders/VCA%20Applications.pdf
Panning for Fun -  http://geofex.com/Article_Folders/panner.pdf
Note Processing for Guitar Effects - http://geofex.com/Article_Folders/noteproc/noteproc.htm

That should get you started. Think about alphabet blocks for a few minutes.

[Dave_B]

Sorry to dig up an old thread. this thread is over a year old and I dont see any commercial examples.

The Toadworks Enveloope might be what you're looking for? 

[nelson]

Wish I had an idea of how to implement it.

Applications of an audio Current Controlled Amplifier -  http://geofex.com/Article_Folders/VCA%20Applications.pdf
Panning for Fun -  http://geofex.com/Article_Folders/panner.pdf
Note Processing for Guitar Effects - http://geofex.com/Article_Folders/noteproc/noteproc.htm

That should get you started. Think about alphabet blocks for a few minutes.

Thanks RG I am halfway there. My god, the possibilities.   

[Mark Hammer]

The Toadworx Enveloope was exactly what came to mind.  Note that it has two modes, one of which brings something in as you play harder, and the other fades something out as you play hard.

You will also note that the Line 6 Echo Park (and the DL4 Delay Modeller, I think) has a ducking mode in which the delay signal recedes during heavy picking, and gets faded back in when the player eases back and gives some "breathing space" for the echoes to be heard.

Compared to keyboard players, guitar players have infinitely more performance controls at their fingertips...and palms...and butt of the hand.    Of course all of this is in service of getting the string moving.  Use of envelope extraction (sidechains) can be put to creative use to control those things your fingers can't do by themselves (or that your feet are presently too busy to do).

In contemporary keyboards, the player has a number of interesting things available to them.  Obviously there are bender wheels and joysticks for parameter changes that can be synced to notes but don't have to be.  There is velocity sensitivity which is explicitly tied to notes.  There is aftertouch, which is loosely tied to note occurrence.  And there is preprogrammed morphing such that notes held longer undergo sonic changes.  On top of this, there are foot controlled expression pedals, as well as breath controllers and other sorts of "gestural control" like the I-Beam.

Of course, what the user wants is not just more control but control that does not interfere with the naturalness of their playing or which does not constrain the way they can have a musical phrase planned out.  For instance, if a wah took a certain amount of time to sweep the filter, its role in playing would be fundamentally different.  It is the speed with which filter changes can be "mapped" onto what the player wants to do that make it such a desirable effect.

Having more things you can control does not necessarily translate into greater flexibility.  If you want to use a joystick or pitch wheel on a keyboard, then you are limited to 5 notes at once, and more specifically, the 5 notes within the span of your thumb and pinky on one hand.  For guitar players, of course, the choices are much more limited since removing one hand from the instrument means you are limited to 6 notes - the open strings!! This is partly what makes foot-controllers and envelope control so important in guitar-generated music.  They both permit the hands to stay right where they are needed.

I'm surprised that no one has produced a foot operated joystick yet.  Was it De Armond or Fender (or both) that produced a volume/tone control pedal where forward-backward and side-to-side movement were both accommodated?  This was of its time, though, and pot-based.  A dual expression pedal that permitted joystick-like parametric control of two sonic features could be easily done in a potless manner with mouse-type technology wedged in a foot-pedal assembly, and you could even have some sort of aftertouch built in there by leaning a little more forward or a little more to the side.  Stick the whole thing on a round sort of "wobble-board" that you could approach from any angle.  Imagine what you could do by leaning a little more into your pedal and turning up the regen/resonance on something, or cranking the drive on a distortion a little more as the note starts to die out.