What is "chorus"?

Tony LaCroix · Post by **Tony LaCroix** » 11 Jul 2003 6:00 am

The "dumbest effect" thread got me to wondering. What exactly is meant by 'chorus' as an effect? I know what it sounds like, but what is actually happening to the guitar signal?

And, as a tag-on question, how can I make my guitar swoosh from one PA speaker to the other, like Robert Plant's voice on the trippy part of "Whole Lotta Love"?

Larry Bell · Post by **Larry Bell** » 11 Jul 2003 6:19 am

The effect you refer to (Led Zep) is called 'flanging'. It was originally accomplished by the engineer lightly pressing down on the flange of the tape reel (outside edge) and re-recording that track with the original, creating a phase modulation effect. Later, in the late 70's and 80's, that effect was duplicated electronically using the analog, and later, digital delay electronics, allowing precise control of how much of the duplicate signal is mixed in and how fast the modulation occurs. Flanging can be used to give a primitive sounding Leslie simultation. Listen to Waylon Jennigs' 'The Wurlitzer Prize'. Moon is using an early electronic flanger designed by some folks I knew at SysTech (used to be a division of ProCo), here in Kalamazoo.

A stereo flanger would be required to do the 'side to side' thing you asked about.

Chorus is similar. It is a 'track on a track' type effect that involves mixing a signal with a slightly delayed and detuned signal. It sounds like two people or two instruments. When used in moderation, chorus can give a very pleasing effect.

So, the short answer is that flanging is the 'swooshing' effect and chorus attempts to make a single signal sound like it came from more than one source, producing fullness. If you use too much, it just sounds phony.

------------------
Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps
[This message was edited by Larry Bell on 11 July 2003 at 07:20 AM.]

Gino Iorfida · Post by **Gino Iorfida** » 11 Jul 2003 6:25 am

Hope this isn't TOO technical, but here it goes.

A chorus effect, (same as a flanger), takes the signal, splits it 2 ways, one signal is passed straight through, and the second is delayed slightly (a few milliseconds). The delay time is also modulated of changed slightly in time with an oscillator, then the signals are mixed together.

the difference between chorus and flange, is the delay time used is greater for one (forget which one now), and with flanger, wider modulation is used, as well as some of the delayed signal is fed back into the delay loop to giver more of a whoosh sound. If you have an old analog delay pedal, you can see how this works, simply by setting the mix where the delay is equal to the original signal, set the repeats/feedback to the lwest setting (one slap), and turn the delay time knob pretty much as low as it goes, now hit a chord/note, and while it's ringing out, slightly 'shake' the delay time knob (only a few deg. of rotation back and forth---like keeping it betweenn 8:00 and 9:00), you will hear the detunign granted not as exact as a chorus would do, but you'll get the idea.

Phase shifter/phaser is slightly different in that they do not use a 'delay line', but rather, split the signal, send one straight through, and the other gets processed through a couple of stages with varying capacitor filters to change the actual phase of the waveform, again mixed at the output (if you cut the straight signal on a phaser, you get a vibrato effect like the old UniVibe pedals could do etc)

Tony LaCroix · Post by **Tony LaCroix** » 11 Jul 2003 7:11 am

These are EXACTLY the type of responses I was looking for. Thanks, guys.

So, what I'm really interested in is simply auto-panning my guitar signal in a live situation. I don't want any detuning of the signal, or any other qualitative change to it. Can this be accomplished with a stereo delay pedal?[This message was edited by Tony LaCroix on 11 July 2003 at 08:12 AM.]

Gino Iorfida · Post by **Gino Iorfida** » 11 Jul 2003 8:05 am

If you want no phasing effects, and want only panning, BOSS made a tremolo pedal a few years back that would do an auto-pan. I think there is also a 'pan pedal' that they currently make If you dont' mind a little 'whoosh' , then a stereo phasor would be the best bet for that then.

I've always wanted to design a pedal that would do the uni-vibe thing, however pan it accordingly, in order to TRUELY get the TRUE leslie cabinet effect thing going, but other than a few effects by some 'jam bands' I dont se emany using it.... something that when playing through headphones, you'd get the illusion that the sound was swirling AROUND your head...

Smiley Roberts · Post by **Smiley Roberts** » 11 Jul 2003 10:34 am

One of the earliest recordings I remember, that features this effect,was "The Big Hurt" by Miss Toni Fisher. I thought,"WOW,how're they doin' that?!?!" The explanations above tells all. Thanx guys.

------------------
<pre> ~ ~
©¿© It don't mean a thang,
mm if it ain't got that twang.
www.ntsga.com</pre>

seldomfed · Post by **seldomfed** » 11 Jul 2003 10:49 am

Tony,
Most of the multi-effects pedalboards have a pan feature that can be used autopan or controlled with the foot pedal. Look at units by Boss, Korg, Zoom. (wow that's almost like onomatopoeia - 'boss korg zoom'

Morley used to have vol./pan/wah pedals - not sure if they still are out there. The new multi-effect units are getting better all the time. The devices primarily focus on guitar player needs (satisfying the distortion fixation syndrome). BUT, on the other hand they are often inexpensive, are a blast to mess with, and will give you new many new ideas.
chrisk

------------------
Chris Kennison
Ft. Collins, Colorado
"There is no spoon"
www.book-em-danno.com

Jackie Anderson · Post by **Jackie Anderson** » 11 Jul 2003 11:37 am

"Distortion fixation syndrome" -- boy, that about says it! I think I've caught a touch of that, myself....

Donny Hinson · Post by **Donny Hinson** » 11 Jul 2003 11:17 pm

Tony, the "detuning" effect of a chorus is noticeable only at extreme settings. The normal settings of a good stereo chorus are quite pleasing, and do indeed produce the "swirling around your head" effect that Gino referred to. Any good tech could whip up a mod to the tremolo in an amp to do the "auto-pan" effect. The resulting sound would be quite "flat", though, unless the amps were phased differently, and there was considerable difference in their tone settings.

Many years ago, I added an extra jack to my Fender volume pedal, and rewired it, so I could do a manual "panning" between two amps. It was a novel effect, but I didn't use it very much. Also, the effect (when used on a two-channel amp), approximated the sound of a phaser or chorus, due to the signals in each channel being 180 degrees out of phase.

Dave Boothroyd · Post by **Dave Boothroyd** » 11 Jul 2003 11:52 pm

My favourite source for information on effects is Harmony Central. http://www.harmony-central.com/Effects/
There you will find everything from sound clips before and after to wiring diagrams and user reviews.
It's a recommended site for my students- well not so much recommended as compulsory really!
On settings, try to get the chorus speed at about the tempo of eighth notes, and if you set the Chorus depth more than about one third, it starts to sound as if you are playing underwater. Don't use too much stereo pan with a room full of drunken dancers- they will start falling over - which can be good fun if you have a sadistic frame of mind!

Cheers
Dave[This message was edited by Dave Boothroyd on 12 July 2003 at 12:56 AM.]

Rich Paton · Post by **Rich Paton** » 12 Jul 2003 12:17 am

Sems to me there was a wild factory preset on my ProFexII, which I haven't used for some time (due to GCIS, GlobalControlIneptitudeSyndrome) which had a quite pronounced "ping-pong'-pan" effect along with raging over=the-top-distortion and other sonic extravaganzae.
In any case, you cats with PFXII's and who are free of GCIS can no doubt set up such a preset.
Smart money says ol' Les Paul Paulverized such bizarre sounds, way long ago.
BTW, to my ears, manual flanging good old Manual Double Tracking sound better than the more sophisticated effects processors can approximate, and Abbey Road's ADT or AutomaticDoubleTracking sounds sterile compared to the huge vocal sound of MDT. Check out George, John & Paul all MDTing on "Think For Yourself", Rubber Soul album. Just HUGE rich vocals done "the old fashioned way".

Larry Bell · Post by **Larry Bell** » 12 Jul 2003 5:25 pm

Rich,
You hit that'n on the head.
Many of the creative uses of effects came from

* Les Paul, who gave us multitrack recording, tape delay, and everything that sprang from it.
* Sir George Martin, who skillfully applied what his predecessors had invented and took the concept of tape loops and splicing to a new level.

I'm sure there were others, but those two were (and are still) known for their creative use of special effects, many of which they invented for themselves to create a sound they heard in their head.

------------------
Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps

Brett Cookingham · Post by **Brett Cookingham** » 19 Jul 2003 10:42 pm

Chorus is usually after the Verse or Bridge

Bill Llewellyn · Post by **Bill Llewellyn** » 20 Jul 2003 5:01 am

I sometimes wonder where the term "chorus" came from in connection with this effect. The name for the Leslie rotating speaker's slow setting was dubbed "chorale" decades ago because the slowly changing timbre it created sounded something like the pipe organ chorale setting which includes a set of slightly detuned pipes, which I think was meant to sound like a chorale of human voices (which are also never exactly in perfect tune with each other). Maybe the name "chorus" is an extension of that.

------------------
Bill, steelin' since '99 | Steel page | My music | Steelers' birthdays | Over 50?
[This message was edited by Bill Llewellyn on 20 July 2003 at 06:05 AM.]

Brett Cookingham · Post by **Brett Cookingham** » 20 Jul 2003 2:15 pm

Doppler effect
Function: noun
Etymology: Christian J. Doppler
Date: 1905
: a change in the frequency with which waves (as sound or light) from a given source reach an observer when the source and the observer are in motion with respect to each other so that the frequency increases or decreases according to the speed at which the distance is decreasing or increasing

'er sumthin like that

B.C.