Modulation Devices – Modulation devices, like we will be discussing, generally work in sync with time delay to create the desired effect. Think of a pitch, doubled and delayed slightly (approximately 10-30 milliseconds for chorus and 5-15 milliseconds for flange), The delayed signal is modulated causing a very slight pitch shift (generally by a device called a LFO, short for Low Frequency Oscillator), and mixed back against the original signal and the effect is flanging or chorus. Other examples could include phase and vibrato here as well as their sounds and applications are somewhat similar, although neither of these effects are created by modulated delay.
Flanging – Flanging (and chorusing for that matter) can be created with a delay. Originally flanging was done by running two identical tape recordings next to each other and slowing one of them a tiny bit. This caused the frequencies in the combined signals to rub against each other creating a shimmering, swirling effect. A great example is Jimi Hendrix’ “Axis: Bold as Love,” done by manually manipulating the recording tape of the song. Needless to say, it wasn’t a simple trick that could be done by stepping on a button. When 70s Bucket-brigade technology made tape delays unnecessary, it opened the door for pedal flanging and chorusing. Some of the groundbreakers:
A/DA Flanger – One of the first and most tweakable flangers, A/DA (short for Analog Digital Associates) was way ahead of its time developing it. You could actually control the flange effect by using picking dynamics and it was considered “studio quiet.” Probably its most famous user was Pat Travers. It was discontinued and reissued in the mid 90s and discontinued again. There is a rumor that Jim Dunlop may be doing a reissue soon.
Electro-Harmonix Electric Mistress – Although Electro-Harmonix was founded in 1968 the Electric Mistress didn’t debut until 1976 (and the deluxe version two years later). It proved an affordable alternative to many of the other flangers on the market at the time. Robin Trower (who used two of them on his pedal board), Paul Gilbert, David Gilmore and John Jorgenson are some well known users. David Gilmore was said to set all three dials at 10:00 for Pink Floyd’s “The Wall.” After Japanese transistor makers started cutting them off because of the growing popularity of Japanese effect makers, Electro-Harmonix was forced to fold in 1981. The products are currently being reissued once again by original founder Mike Matthew’s company New Sensor.
MXR Flanger – Another effect made famous by the legendary tone of Eddie Van Halen. All the sweeping flange sounds that we hear on the “Women and Children First” CD were created by the MXR Flanger (“Unchained” and “And the Cradle Will Rock” come to mind). Randy Rhoads was also a user. It was discontinued in the 80s and reissued again in the mid nineties. MXR got its start in 1972, but like so many other American guitar effect companies, eventually fell victim to cheaper Japanese imports coming in during the mid 80s. One of the original founders, Keith Barr, would go on to form the now famous Alesis, while the other founder, Richard Neatrour, went on to start Applied Research & Technology (ART).
Chorus – Working similar to a flanger, chorus uses a slightly longer delay to create a wider or more spacious sound. The chorus is meant to create the effect of a twelve string guitar or doubled part. Like the flanger, Bucket-brigade technology made foot pedals possible. It is safe to say that the Japanese company Roland was most responsible for making the electronic chorus effect as popular as it is. They introduced it with their 1976 CE-1 chorus pedal and also in their JC-120 Jazz Chorus amp.
Boss CE-1 – Coveted by guitarists for thirty years, the big analog Boss CE-1 probably started the whole chorus phenomena. Known for its warmth, this is the pedal that gave Andy Summers his trademark guitar sound used so masterfully with the Police. (as in “Walking on the Moon”). John Frusciante and Adrian Belew are known users.
T.C. Electronic Stereo Chorus – Popular for over two decades, T.C. Electronics stereo chorus has been a very popular unit for many guitarists. The ultra clean, pristine tone coupled with being relatively noiseless compared to many other popular units has led to its reputation as one of the finest analog choruses available. Besides stereo chorus, it also features Pitch Modulation and Flanging and provides both stereo and mono outputs. Eric Johnson has been known to use one.
Dytronics Tri-Stereo Chorus – Although it is no longer being manufactured, the Tri-Stereo Chorus is a very sought after chorus featuring a chorus setting for left, right and center for an incredible, wide sound. Studio aces Mike Landau, Steve Lukather and Dan Huff are among the users. Fulltone is said to be making a reissue shortly for a reasonable price.
Arion SCH-Z – Strangely enough, this incredibly inexpensive chorus is very popular with many studio musicians. It is very lush sounding. Being as inexpensive as they are, there are a few problems, durability being one, volume loss another. Also it is not true bypass. The good news is that you can purchase an already modded one from E.W.S that eliminates all these problems. The E.W.S mod adds a vibrato feature as well. Even with the mod, this pedal is relatively inexpensive (about $200) compared to some of the other products showcased. Some known users include Mike Landau and Scott Henderson.