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The big mystery revealed…

Common questions that get thrown our way here at Dawsons include “What is modulation?”, “What’s the difference between flanger and phaser pedals?” and “Where do you put a flanger/phaser pedal in your signal chain?”. Without diving too deeply into the world of electronics – there are universities for that sort of thing – we’ll try to demystify modulation effects. We’re going to cover Flanger and Phaser pedals, and we’ll even give you some pointers on pedalboard placement.

What is modulation?

When it comes to something like overdrive or distortion, the concept is simple. Increase gain at pre-amp stage, sound more METAL! Increase gain at power-amp stage, finally, you can hear yourself over the drummer! It is fair to say that when applying modulation, there is an audible impact on tone. However, understanding what is happening to the signal gives you greater control over your setup.

A “dry” signal refers to the input that remains unchanged, and the altered signal is “wet”. With regard to modulation effects (flanger/phaser/chorus), a copy of the dry signal passes through a series of filters, which is then fed back into the dry signal to create the effect. In the case of flanger there’s a slight time delay involved. The results of modulation can range from a slight whooshing sound to the sound of what appears to be an airplane soaring by.

Not just a phase(r)…

Terrible pun aside, phaser pedals have been on the scene for decades and utilised by guitarists from Jimi Hendrix to John Petrucci. From the classic Uni-Vibe to modern day multi-control units such as the BOSS PH-3 Phase Shifter, there’s a wide range to choose from, but how do they actually work?

Phaser pedals operate based on the principle outlined above. A (dry) input signal splits into two parts through separate dry and wet paths. The wet signal passes through an all-pass filter – or in some cases multiple filters depending on the complexity of the FX unit. Filters maintain amplitude whilst altering the phase (known as phase-shifting). You can attenuate the filter’s position using a Low Frequency Oscillator (LFO) before combining it with the dry signal. Thanks to the actions of each filter, the opposing signals oscillate (come together, move apart, come together, move apart, etc.) and create the “phaser” effect.

Controlling that phase

Obviously, there’s going to be variations on the theme, but you’ll generally find a consistent set of controls that are common across many phaser pedals.

First, there’s the Speed/Rate dial, which adjusts the speed/rate of the LFO that affects the all-pass filter(s). From low to high you can take your tone anywhere from a shimmering wobble to a swirling vortex.

Secondly, the Depth dial adjusts difference between the highest (peaks) and lowest (troughs) points of the wet signal waveform. Again, the higher the setting, the more pronounced and ‘phasey’ the effect.

Thirdly, a Level dial adjust the dry/wet mix to control how much of your original tone is present. You can take it from subtle hint of wet signal to an unrecognisable dry tone.

Last of all, a Feedback dial enables attenuation over the wet signal fed back into the dry signal path. For those who like their phase with a touch of overtone, then the feedback dial is like manna from heaven.

Primo Phaser pedals

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The Electro Harmonix Nano Small Stone is a diminutive little pedal that can produce tones that will illicit profanity laden utterances. Many a guitar legend has turned to the Small Stone at one point or another and if you want an idea of what it can do, check out the Smashing Pumpkins’ legendary tune “Mayonnaise”.

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Another amazing little pedal is the MXR Phase 90, as used by Pink Floyd on their seminal track “Shine On You Crazy Diamond”. Nuff said.

Flanging back in the day

Depending upon what you read there are several individuals who allegedly coined the term “flanger” or “flanging”. What we do know is that to achieve a “flanger” effect back in the 1960s, a finished track was recorded simultaneously to two matched tape machines then replayed in sync. Playback-head output was then mixed down to a third tape. However, one of the tapes was slowed down ever so slightly by applying pressure to the rim (flange). From here the sound of the slowed down tape causes a swooshing watery sound. Engineers switch back and forth between the tapes to recreate the effect when desired.

You can appreciate examples of flanging in The Small Faces “Itchycoo Park”, Heart’s “Barracuda” and Rush’s classic “The Spirit of Radio”.

Thankfully, advances in music tech means that today we can get the same results from a handy effects unit.

Fantastic Flanger Pedals

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When it comes to guitar effects, anybody and everybody from amateur to touring professional has a BOSS stompbox somewhere in their arsenal. Owing to their robust construction and affordable price point alone they are exceptional. However, the tonal sculpting brilliance of their hardware is what makes them the industry standard. The BOSS BF-3 Flanger is an outstanding unit that offers elaborate stereo mono or stereo flanger control. From a subtle watery wash to the sound of a spaceship speeding through the cosmos, the BF-3 is an absolute gem of a pedal.

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However, for those who demand even more Flanger for their money, then the Dreadbox Komorebi Analogue Chorus Flanger is limited only by your imagination. Seriously, there is more going on in this thing than the stripped back control panel may initially imply. There are multiple waveform types, variable feedback operation, rate adjustment and the ability to incorporate several instrument types. Komorebi have basically thrown everything into their glorious Analogue Chorus Flanger – and it doesn’t look too shabby either.

Pedalboard placement

When it comes to pedalboard placement there is an age-old argument between whether or not to put a modulation effect before or after your drive/distortion pedals. Some swear by leaving it at the end of the signal chain to offer a shimmering quality to your already driven tone. The reason for this is that signal remains consistent when passed to the flanger/phaser.

However, should you opt to go with phase before drive like Eddie Van Halen, you’re free to do so. Fluctuations in signal caused by the sweep of the flanger/phaser effect can have an unpredictable effect on tone when overdriven. If you’re aiming for a Melvin’s-esque doom-laden muddy fuzz, go for it! After all, there are no rules when it comes to how you set up your pedalboard. Plus, more reasons to buy more pedals to experiment with, huzzah!

Here’s a handy video tutorial that we made earlier (you’re welcome).


In the simplest terms, Flanger and Phaser pedals are both variants of modulation effects. They both share the quality of having dry/wet signals mixed together to create their effect. However, Flanger has a delayed signal that when fed back in with the dry signal causes that classic whooshing sound.

If you’re looking to add a bit of colour and texture to your tone, then spicing things up with some modulation is the way forward. Whether you’re cultivating clean licks that shimmer and shine or thundering through some beefy metal riffs, they can do it all baby. They play well with others in your pedalboard, and as you can see from the examples above, you don’t need to break the bank to get your hands on one.

Hopefully, we’ve given you enough insight into the difference between flanger and phaser pedals. Head over to the Dawsons website to dive into the rest of our awesome guitar pedal selection.

As ever, if you need any help or advice then our Customer Service Team are more than happy to help over the phone on 01925 582420. Our in-store specialists will guide you through the wonderful world of guitar effects, just pop into your nearest Dawsons store.

Quick recap of the pedals highlighted in the article: