Whooooooosh. The Wonderful World of Flanging
Here I discuss what a Flanger guitar/studio effect is and how it does what it does. It's a more versatile effect than it might seem.
When a guitar player hears the word Flanger, most people might think of the whooshing jet takeoff effect of “Barracuda” by Heart, “Unchained” by Van Halen or “Primary” by The Cure. Those might be the most obvious uses of the effect, but it is far more versatile than it might seem to those who have never experimented with one. I will try to explain what it does, how it does it and why you need it!
My first experience with a flanger was when a friend let me borrow his, then current, now very vintage Electro Harmonix Electric Mistress pedal for a few days back when I was twelve years old. I was completely mesmerized by the silver and green box and its otherworldly sounds. It had some very “synthetic” tones in it and I was really drawn to that. At the time, I was obsessed with making a guitar not sound like a guitar and more like a synthesizer. I turned every knob and switch every which way, trying any and every combination the thing was capable of and I was hooked. I can still remember that experience like it was last week.
Flanging, as a concept, has an interesting story. It was a special effect developed out of experimenting and trying to create a unique sound in the heyday of developing electronic recording. It was developed in the 1950s and the first commercial record released with the effect was “The Big Hurt” by Toni Fisher. The whole song swirls around with the effect. It’s a very ethereal and pre-psychedelic sound. It would later come in very handy in the 60s, when psychedelic rock came to the forefront with songs like “Itchykoo Park” by the Small Faces, “Tomorrow Never Knows” by The Beatles, “Sky Pilot” by The Animals and it was used to great effect in stereo by engineer, Eddie Kramer, on Jimi Hendrix’ “Bold as Love”.
Until the 1970s and the development of “bucket-brigade” analog delay circuits (and later digital delays), flanging was done with reel-to-reel tape. The term, flanging, itself seems to come from the fact that it was produced by putting your hand on the flange of a reel of tape. How it works is that you would have two reel-to-reel tape machines running simultaneously. You would send the same signal to both of their record heads, and monitor both of them off the playback head, which is an inch or so after the record head, thus there is a bit of a delay between what the record head records and what the playback head hears. When all was running, you would hear a blend of the two tape machines in sync. Nothing crazy there. When one would lightly press a finger against the flange of one of the machines’ tape reel, essentially slowing the tape speed down a bit. It made the time that the tape would pass over the playback head a tiny bit later than what the other, untouched machine was doing. You would all of a sudden hear this incredible whoosh as the signals from both machines created an ever-changing comb filtering and effect due to the phase cancellations at certain frequencies with such a short delay time (we’re talking around 2 to 6 milleseconds). You let go of the tape reel, and it would whoosh back to correct speed and all would be in sync again.
So what did we learn here? Well the concept is that a dry signal is combined with a very slightly delayed signal to create phase cancellations. The frequency of the phase cancellations is dependent on the delay time. For example, the shorter the delay time (i.e. the closer the delayed signal is, in time, to the dry signal) the higher “pitch” the phasey sound is. The longer the delay time, the deeper the “pitch”. If you continued on with even longer delay times, you would eventually pass into chorus territory (around 20-30ms), then “double track,” (around 50-90ms) then slapback (around 100-120ms), then what we perceive as a discrete echo effect (around 200ms and longer).
Traditionally the delay times in a flanger are really short. Most seem to be centered around 2 millseconds, sweeping shorter and longer, but usually centered around 2ms. Once you get too far away, closer to 10ms and longer, you start to lose the phase cancellation effect and get more of a discrete echo or slap.
With that concept in mind, any delay unit that can get down to 1 or 2ms, you can start to create flanging effects. So how does it whoosh? There is a circuit called an LFO, or low frequency oscillator, which is part of almost any audio effect that has a sweeping cycle, or period: the back and forth action of a chorus, phasor, vibrato or tremolo, for example. If you have a little knowledge of electronics or how old-school analog synthesizer modules work, then this concept should be pretty simple. Essentially, you are varying a voltage, back and forth, up and down. How high and low the voltage goes (the range) is controlled by a knob called WIDTH, DEPTH, RANGE, etc. How fast the voltage changes back and forth is controlled by a knob called RATE or SPEED.
The voltage output of the LFO circuit is sent to a part of the circuit which handles the delay function. The varying voltage controls the delay time. If you set the LFO width/depth to zero (i.e. no sweep) then you have a set delay time. Usually a flanger pedal has a knob called MANUAL which is a static delay time control.
So let’s see how all of this makes practical sense:
With the RESONANCE or FEEDBACK control turned all the way off, (we’ll explain that later) setting the DEPTH to zero, and turn the MANUAL knob, you will hear the flanging effect as you sweep the knob around. YOU are taking the place of the LFO in this setting. (A small few commercial pedals give you control over this function externally, so you can sweep the flange effect with a footpedal, including the old A/DA Flanger and the old Morley Pro Flanger.)
While turning this knob, you might find a couple of spots that sound particularly cool to you. There are two that I like. One, on the lower end of the control, which is near the longest delay time gives you this rich and deep, slightly out of tune effect. This is similar to a chorus effect. Leave the manual knob set there. Now, with the RATE control somewhere in the lower third of its range (slow to medium slow), slowly increase the DEPTH control until you start to hear the effect swirl. This is a great effect instead of using a chorus. It’s a lush swirl that gets you the familiar modulation effect used by Andy Summers of The Police, Pat Travers and David Gilmour of Pink Floyd.
Now turn the DEPTH back down, and turn the MANUAL up toward the other extreme of the knob. You should start to hear a hollow filtery sound similar to the effect of setting a wah pedal in one position. Turning up the RESONANCE or FEEDBACK control will make this effect more pronounced. Very slight, if any RESONANCE, run through a distorted amp, is a neat alternative to the cocked-wah effect for a Michael Schenker or George Lynch 80’s metal tone (or one of my favorite tones, the late David Lindley’s lead guitar on Jackson Browne’s “That Girl Could Sing”, though I’m not sure that flanging was used for that). Turning the RESONANCE up higher gets you into resonator land. If your flanger pedal allows (there are small adjustable trimpots inside that usually set the limits of the feedback control), you can create neat runaway “bathtub reverb” effects in this setting. A favorite of Adrian Belew/King Crimson as heard on “Genius of Love” by Tom Tom Club.
So what is this RESONANCE/FEEDBACK control doing? Well, if you’re familiar with a delay unit, you might have figured out that it’s just like the FEEDBACK control on a delay. It sends the output of the effect back into the input in a small degree. The higher the feedback, the more echoes. Since a flanger has such a short delay time, you’re not necessarily hearing repeating echoes, but instead a sharp pinginess that sounds like you’re talking through a vacuum cleaner hose.
So by now, you’ve figured out that a slow RATE, a high DEPTH and a moderate RESONANCE gives you that classic jet-like whoosh that you hear in “Barracuda.”
You may notice that when the WIDTH/DEPTH control is turned up, the MANUAL control becomes ineffective. That should make sense if you’re thinking of it electronically. The MANUAL control is setting the center frequency (delay time) of the flanging effect. The DEPTH is sending the LFO’s control voltage to the same part of the circuit that the MANUAL is controlling, so they’re really doing the same thing. When the DEPTH is lower, you’re sweeping around the particular delay time that the MANUAL is set to. Those controls are interactive, provided that the DEPTH control is not up all the way.
Here’s where the more advanced stuff comes in...
Why doesn’t my Boss BF-2 sound like “Killer Queen”?
Well, if you recall the initial explanation of the tape flanging effect, one very important bit that I didn’t mention is that when you’re running those two tape machines against each other (analogous to the dry signal and the delayed signal in a flanger pedal) you actually have the ability to have them sync back up to a “zero delay” time. A standard flanger pedal CANNOT do this, because it’s impossible for its delay time to get to a true point of zero. (I say standard because there are some ways to do this, but not in a $40 flanger pedal.) It’s that point of zero delay which gives the most incredible and characteristic mind-bending whoosh of psychedelia that flipped out all those crazy kids in 1959 when they first heard “The Big Hurt.”
So how can we get that effect with effect units? I’ll explain a few options and a few other cool tricks along the way.
Most flanger pedals do not give you an effect level or blend control. The typical flanger has those four knobs of MANUAL, DEPTH, RATE and FEEDBACK. If you understand the above concepts of how a flanger works, you can see how any older 80’s digital delay rack unit, and one of my favorites is the famous bright blue Deltalab Effectron II, can quickly become a flanger. I will use that effect as an example, but you can use almost any dedicated delay in this way. Setting the LFO (also called MODULATION, by the way) to sweep a short delay time of around 2 or 3ms, with a moderate FEEDBACK, and the EFFECT MIX set in the middle (equal dry and equal delayed signal) you will hear your favorite jet-flanging effect.
Now, if you turn the EFFECT MIX control counter clockwise, you’ll hear JUST the dry effect. Turn it up and you’ll hear JUST the delayed signal. Hey, wait? Where did the flanging effect go? Well, if you recall, the effect is achieved when the delayed signal changes AGAINST the dry signal, creating phase cancellation effects.
Hmmmm..... the lightbulb goes off over your head.
So what if I have two of these Effectron II units that I picked up from that old sound man’s yard sale.... What if I set them BOTH to 100% wet mix, and set them both to the shortest delay time, with NO modulation or feedback. What if I send the same signal equally to both of them, then have them both return to two channels of my mixer, and set the levels of them both equal (with your ears) and panned mono. Well, you shouldn’t hear any flanging. If they’re set to the same exact delay time, you essentially have two tape machines running alongside each other. Now, if you slowly and slightly vary the delay time of ONE of the delay units, you will hear the flanging effect, just as you did with the stompbox. Instead of it flanging against a dry signal, it’s flanging against the minutely delayed signal.
Except now, you can get them both to “zero delay” against each other, and even go the “other way” and get them to cross the zero point. You will find that with the DEPTH set a certain way, you can get really cool lop-sided modulation effects, where the “center point” which is determined by the stationary (not modulating) delay is NOT at the center of the sweeping delay’s modulation range. Trial and error. You’ll get it happening.
Now that we’ve found the wonders of the EFFECT MIX control, let’s see what else we can do. Go back to having ONE unit set up. Run your guitar through it. Set the MIX to 100% wet, and set the delay time for around 5ms (trial and error will get the best result here) with NO feedback. Set the RATE to a faster setting, and slowly turn the DEPTH up until you hear a vibrato effect. Unlike a chorus set to a fast rate, this is more of a “true vibrato” in that there is no dry signal, just a sound that’s wobbling up and down in pitch. Turn the rate down and the WIDTH up for some total seasickness.
Now, let’s talk about some particular flangers and what makes them cool.
A/DA FLANGER: This 1970s holy grail is great and unique for a couple of things. One is that it has a very wide sweep range on the LFO so it can get more extreme than other flangers. Another is that it has a CONTROL PEDAL input that lets you sweep the flange with a footpedal or a control voltage from an external source. Another is the ability to do NEGATIVE (inverted) flanging! What does that mean? Well, it takes the delayed signal and inverts the phase from the dry signal, which gives a whole new type of hollowness to the effect. It’s more like a phasor, but still like a flanger. Very pukey and cool. Listen to the guitars in “On Top of the World” by Cheap Trick or “She’s in Parties” by Bauhaus for a good example. This pedal also includes a variable noise gate JUST on the flanged signal, so you keep it nice and quiet. Old bucket-brigade analog delay technology tended to be quite noisy, especially at longer delay times. The Electric Mistress doesn’t have the noise gate, so it’s quite a noisebox on its own. I like that too...
MXR FLANGER 117: the gray box is pretty much the quintessential four-knob flanger. It sounds great in all settings, though to that end, it doesn’t have as wide a sweep as the A/DA Flanger. It is one of the most robust and meaty sounding boxes out there. This is the “Unchained” pedal.
ELECTRO-HARMONIX ELECTRIC MISTRESS: I already brought this one up. What is so cool about this one is that the waveform of the LFO (remember, the part that sweeps back and forth) is more of a sharp triangle wave than a smooth sine wave. This makes it sound very extreme when it bounces off the limits of the modulation... it sweeps back sharply and suddenly. This gives it a more out-of-tune effect than other flangers. That’s why it’s my favorite for more “chorusey” effects, and its killer for the Police sound. It also has what it calls a “FILTER MATRIX” which is just fancy (and confusing) terminology for “shut the LFO off and use the MANUAL control to get those clangy comb filter effects.” A true masterpiece of flanger pedals. The Electric Mistress came/comes in various versions. They SHOULD all be able to do similar things, but I’ve got no experience with the modern ones, and especially the Stereo Electric Mistress, which I believe is digital. I have two different versions of the original 70s Mistresses which used 2-9V batteries. I also have a vintage and a reissue Deluxe Electric Mistress, which had built-in power supplies with an AC power cord.
BOSS BF-2: This was Boss’ second and probably most successful foray into Flanging. This lovely purple pedal is hard to beat. Like most other 4-knob flangers, it will do most of what you need it to do, though it might not have the most distinct personality, it will always sound great. My guess is that this is the sound of “Primary” by The Cure. Does all my favorite flanging effects from the slow jet whoosh to a fast “Leslie” speaker vibrato effect.
BOSS MICRORACK RBF-10: Total sleeper and total keeper. This was from a short-lived and maybe miss-marketed series Boss put out in the mid-80s. It’s similar to the BF-2 circuit, except that it gives you an EFFECT MIX control to balance between wet/dry (unlike almost any other flanger) and even cooler, there is a patch point on the back for a MODULATION BUS: this lets you control it’s sweep from an external LFO, a C/V pedal or another Microrack effect. You can do the absolute coolest pseudo-random flanging effects with this by combining another LFO with its own, both set to different speeds. This ALSO lets you do negative feedback flanging like the A/DA.
It's also important to discuss where to put a flanger in the chain of effects, especially before and after distortion, but I will cover this in a future article. I should also write something about stereo flanging, which is my favorite way to get seasick!
For further reference, check out modezero.com which is an invaluable source for examples of many different modulation effects with soundclips. Also you can search YouTube for demonstrations of various flangers.