Chorus and flanger are two iconic guitar effects, and they are both forms of modulation. Though these effects get used every day by pros and amateurs alike, a lot of guitarists don’t even know what these effects actually are and how they function.
In this article, we’re going to take a closer look at chorus and flanger. We’ll review their history, analyze how they actually work, and talk about the sounds they produce and why people use them. Hopefully by the end of this article, you’ll actually know what all those knobs on your pedals are doing.
Chorus is more common, arguably more practical, and was invented first—so let’s start there.
What is Chorus?
So first off, what even is chorus? It’s that effect that adds that weird lush warble to your sound, but what’s actually going on?
Chorus basically mimics the effect of a real chorus. When a group of singers sing, they will sing the same note, but with slightly different pitch and timing. This creates a unique shimmer effect that adds a lushness to the sound.
Chorus pedals and effects aim to reproduce this effect, but without needing a circle of guitarists or a bunch of overdubbing. Initially, you might assume that this is done by modulating the pitch of your signal, but that is not the case.
Chorus works by slightly modifying the delay time of your signal, typically done with a low frequency oscillator (LFO). This causes a constant phase shifting between the two signals, resulting in the lush chorus effect we all know and love. Choruses create multiple copies of the signal to modulate, while flangers only make one.
Choruses generally have delay times between 15-40ms, which is much longer than what is used for flangers. And as a rule of thumb, a slower speed/rate results in a more subtle effect, while a faster speed/rate results in a more noticeable effect. Keep this in mind next time you’re fiddling with knobs on your chorus pedal.
History of Chorus
With the technical details covered, let’s move on to how the chorus came about. Surprisingly, chorus dates back to the 1930s. Hammond actually began including the effect with some of their organs, and it became a popular sound. However, it was still an organ only effect at the time. If guitarists wanted to emulate that sound, they’d have to manually double track their parts again in the studio.
As the 50s and 60s rolled on, more and more guitarists were experimenting with effects like tremolo, vibrato, and more. A big turning point for chorus was when the Beatles utilized artificial double tracking (ADT) to achieve a chorus effect. This created a huge demand for ADT and the chorus effect.
However, things really started to change in 1975 when Rolan introduced the now-iconic Roland JC-120. The amp is known for its incredible cleans and most importantly, its three dimensional space chorus. Guitarists like Jeff “Skunk” Baxter, Adrian Belew, and Andy Summers quickly fell in love with amp and its chorus, making chorus an even more popular and in-demand effect.
The chorus in the JC-120 was so popular that Roland ended up releasing a pedal version of it—the CE-1. This pedal enabled countless guitarists to plug in and experiment with chorus. They also released a smaller version in 1979, the CE-2, which cut the vibrato and stereo output to keep a smaller footprint.
With chorus pedals widely available going into the 80s, it’s no surprise that chorus was a popular effect at the time. From Bruce Springsteen and David Bowie to Def Leppard and Living Colour, the chorus was everywhere in the 80s.
The 90s weren’t as kind to chorus as the 80s, but chorus still saw plenty of use. Nirvana’s iconic Come as You Are features chorus, as does Metallica’s Enter Sandman. Chorus may not be used as heavily now as in the 80s, but it’s still an incredibly common effect used all the time.
Now that we’ve talked about chorus, let’s move on to its sibling—flanger.
What is Flange?
To start, let’s quickly recap how chorus pedals work: they take the signal, make multiple copies of it, and greatly manipulate the timing of those signals with a LFO. Now, keep that in mind as we talk about flangers.
Flangers operate very similar to choruses, but with a few key differences. Starting at the top, flangers only make a single copy of your signal, as opposed to the multiple copies a chorus makes. The timing of those signals is manipulated much less than a chorus, typically only 1-5ms (choruses are 15-40ms).
Because the signal is only copied once and manipulated less, it actually results in more frequency interference. And on top of that, flangers actually slightly modify the delay over time as well. This all results in a phase shifting process that lets the waveforms phase in and out of being in sync.
The result is that iconic jet plane sounding filter sweep. Flangers aren’t nearly as common as phasers, but they can still be a great asset to your pedal board. They can be great at adding a little more space, atmosphere, or texture to a part, as well as being a great tool for building a section of a song.
Before moving on, let’s also quickly touch on infinite or “barber pole” flanging. This is an interesting technique that’s possible with flangers. It can create a sonic illusion similar to a shepard tone effect, where the flange seems to only go in one direction (up or down). This effect utilizes multiple delay lines fading in and out of the mix.
History of Flange
Now, let’s spend a little time looking at where flangers came from and how they came about. The history of flange dates back to the 1600s. A Dutch mathematician named Christiaan Huygens first discovered the concept of flanging in 1693, though it wouldn’t be until much later it was actually used in music.
After that, the origins of flanging are actually somewhat argued. Les Paul discovered the effect in the late 40s or early 50s. He used acetate disks on variable-speed record players to slightly modify the speed of playback, creating a flange effect. However, George Martin of Beatles-fame argues that he and Lennon created the term flange.
Regardless, flanging evolved further in 1966 when engineer Ken Townsend invented ADT. As mentioned above, the Beatles and other bands utilized ADT to create chorus effects, but it also worked for flange as well.
Tape-based flanging continued to evolve throughout the 60s and 70s, until solid-state electronics came along. Just like with chorus, solid state technology made flanging possible without needing a pair of tape decks. Integrated circuits and the famous bucket-brigade chips made flange pedals possible.
By the mid 70s, numerous companies like Boss, Electro-Harmonix, Eventide, Ibanez, and more already had flangers on the market. From there, flange became another tool in the tonal arsenal of guitarists.
That said, flange never quite caught on like chorus or other effects. It’s always been a common effect, but not one that gets used incredibly often. It never seemed to have a moment in history like phase, wah, or chorus had. Still, it’s an incredibly iconic effect that every guitarist should try at least once.
Modulate and Make Something New
Chorus and flange are two of the most popular and iconic guitar effects. They both operate on similar principles—modifying your sound by copying and delaying your signal—but they use different techniques to create wildly different sounds.
Which do you prefer? Chorus or flange? The only way to find out is by giving them a shot and seeing how it sounds. So grab some pedals, start modulating, and make something. And of course, don’t forget to string up with a fresh set of Stringjoy strings.