Andy's Tone Tips: What's the Difference Between Chorus and Flanger?

THE GIST
  • A chorus effect is achieved by copying your signal one or more times and playing back the copy or copies at a slight delay behind the original.
  • A flanger effect also uses a copy of your signal, but modulates the copy in and out of phase with the original. (In some units, the original signal is modulated as well.) The resulting delay times vary, but are shorter than a chorus effect.

If asked to articulate the differences between a delay and a reverb effect, or even between a fuzz and an overdrive, you'd likely have no problem giving a clear answer. But when the effects in question are flanger and chorus, the answer might not come to you as quickly.

Today, Andy is here to fix that with another of his Tone Tips videos.

Andy starts by explaining chorus, which is the simpler and more straightforward of the two to grasp. Chorus thickens up your guitar tone by copying your signal—often doubling, but sometimes creating many multiples, depending on what chorus effect you're using. Then, the copied signal or signals are played back at a very slight delay to the original. (Andy's delay time in the video above is only around 20 milliseconds).

The result with most chorus units is a thicker, doubled sound that can sound fluid and wavelike. If using a multi-voice chorus effect, the resulting combined sound can even more closely resemble an actual choir—with multiple voices singing the same part at once.

A flanger effect, while newer to pedal form than chorus, has been used in popular music for longer. The effect was first used in the studio, with an engineer playing two tape decks with the same music on them simultaneously, speeding up and then slowing down one of the decks by touching the flange (the rim of a tape reel). The signals, when combined, move varyingly apart and irregularly meet up. If the signals are flipped to 180°, as they are in "negative" flanging, they'd achieve perfect phase cancellation. The sound of both signals moving out of phase and wavering around this zero point creates a sweeping comb filter effect.

The most common flanger effects boxes modulate the doubled signal only and get as close to a 0ms delay as possible, but true "through-zero flanging" has been put into pedal form by Mr. Black, Foxrox, EarthQuaker Devices, and other builders. It's quite a bit more complicated, as the original signal must also start at a slight delay so that the modulated signal can get ahead of it and pass "through zero."

After explaining both effects, Andy digs into the sonic possibilities with the help of the EarthQuaker Devices Pyramids Flanger and Walrus Audio Julia Chorus/Vibrato. Be sure to watch the full video above, and if you have tone questions of your own that you'd like to see Andy answer, email your questions to askandy@reverb.com or let us know in the comments below.


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