The Wah pedal, wah-wah, wow-wow and cry-baby - these are some of the names you may have heard for one of the most recognisable guitar effects in the industry - the wah pedal. On a quick side note, the name ‘Cry Baby’ is a model name given by Dunlop to their version of the effect.
It is unlikely you will find a pedalboard that doesn’t have some version of this effect on it, or at least a way of achieving it. I was reluctant to buy one at first, but I had to when a show I was performing required one - I am glad that I did! However, much like using a Floyd Rose-type system for the first time, you have to learn to use it in moderation; you will quickly become obsessed!
History
Legend has it that an engineer from the Vox company, famous for the AC30 amplifier amongst others, and a session guitarist in the studio came across an effect caused by manipulating an amplifier's controls in a specific way. The control in question, a knob for controlling part of the EQ for the amp, was isolated and melded into a floor pedal format. This all happened in the mid-1960s, and at the time there were various other effects pedals in existence, so controlling a sound with your foot was not a ground-breaking discovery by any stretch.
Despite some initial corporate confusion, the idea was mass-produced soon after the initial discovery and started to pop up all around the world. Only towards the end of the 1960s did the pedal really take off! The rest, as they say, is history.
What It Is/How It Works
As discussed above, the idea came from someone manipulating the EQ controls on a guitar amp. The section of the circuit in question changes the ‘mid’ frequency values, and it is the ‘sweeping’ up and down of this control that gives the effect the signature sound. Different manufacturers have their own take on this since the early days with Vox, but the core remains the same.
Sometimes the effect is referred to as an envelope filter, and can be replicated with software quite easily. The middle frequency range used is typically very narrow, and is boosted then moved up and down the spectrum by altering the position of the pedal with your foot. The picture you see below is a visual representation of the wah effect, replicated with a EQ plug-in in a DAW. The red highlight point you see is basically the wah-effect, and moving your foot will shift that point to the left, or to the right depending on how you are controlling things.
To actually control the pedal, a potentiometer is mounted horizontally inside a pedal that is roughly the length and width of the average human foot - this will make sense in a moment. The top plate of the wah pedal is mounted on a hinge, so you can rock it backwards and forwards by applying pressure with your heel or toe (tricky in high heel shoes, but possible!). This movement manipulates the potentiometer and that is how you control the effect. There is also a footswitch activated when you press your toe fully down - this allows the effect to be switched on and off.
Other versions of the pedal can rely on optical sensors, pressure on the pedal itself negating the need for a switch for activation and some even have extra controls to shape the sound further - as I mentioned before, this core of the effect is still the same.
Famous Examples
Here I want to talk about three examples that are either excerpts that I really love, and also some that need mentioning due to how famous they are.
Dream Theater - The Enemy Inside
Guitar legend John Petrucci uses a wah pedal in this song a few times, though it is particularly clear here at 4:45. He uses the effect to accentuate the accents of the big chords he is playing, and it adds some more depth that you might not find with a straight ahead distorted tone.
Petrucci actually has his own signature wah pedal with Dunlop - this is probably a good thing as he does use it frequently for this reason. You also hear it being used with single note lines throughout this song and countless others.
Jimi Hendrix - Voodoo Child (Slight Return) Live
A classic live performance, and one of exceptional quality. You can see him actually using the wah pedal and he frequents it throughout the tune. Even though he sadly passed away in September of 1970, his use of the effect, amongst others, became world famous and remains so to this day.
It is uncommon for guitar players to posthumously be granted a signature piece of gear. Despite this, and that Hendrix nearly always used a Vox wah, Jim Dunlop also created a Jimi Hendrix version of the pedal. I imagine this is a tribute to the late artist, rather than to produce any specific developments with the pedal itself.
Learn more about Jimi Hendrix in Ryan’s blog post linked here!
Metallica - Enter Sandman
Say what you want about Kirk Hammett’s playing, something I could go on for hours about, you cannot deny the impact he has made alongside his brothers in Metallica. He is one of the few guitarists that are immediately associated with this effect, the link above is a classic example of what he does with it.
This could also be used as a lesson of how not to use the pedal. I cannot think of a solo that Kirk has played that does not feature a wah pedal. In fact, he was recently quoted as having a collection of over 200 wah pedals - I think it is safe to say that he is slightly obsessed with them at this point! Regardless, he has a signature sound and that is more than can be said for a lot of people.
Three Ways to Use a Wah Pedal
Keep an eye out for a short video where I demonstrate the three uses we will learn about now (or perhaps it can be embedded below at a later date!).
Pulse
This technique is very simple, and just requires you to move the pedal as if you were tapping your foot in quarter notes - you should follow a strict pattern and what you play on the guitar will always be affected in the same way.
Despite many arguments online, I think that the Hendrix song linked above, Voodoo Child, used this method for the majority of the intro.
Accentuating Chords/Beats
This can be performed in any way you wish, and really depends on the part that you are playing. The idea is to accent particular notes or chords that you play, something that can be done quickly, like in the Dream Theater song above, or slowly such as in the Joss Stone song ‘You Had Me’ that I have linked below (coincidentally, it was this very song that I needed to by my first proper wah pedal for!).
Joss Stone - You Had Me
Long Sweeps
Joe Satriani - Surfing with the Alien
This song features the guitar effect in question a lot, pretty much through the whole thing. However, it always seems to be in a different way, combining all three of the techniques discussed here.
I would like to point your attention to some of the longer, flowing legato lines that slowly, gradually and carefully sweep through the spectrum over a long, extended phrase. This is great when used as a climax to a solo, and almost acts like a crescendo as you reach the peak.
Final Thoughts
Do not get caught up in the hype of getting a wah pedal until you need one, as this will show restraint and hopefully prevent you from relying on it too much in the beginning. That is how I started and would recommend it to anyone! The world is only big enough for one wah superfan!
I would also like to quickly point out the difference between an autowah and envelope filter again. An autowah is typically based on time parameters, so they effect happens at set intervals, to use this to the fullest potential, you must either play to a click track or use a tap tempo function if available. An envelope filter is very similar, except the effect is controlled by how dynamically, hard or soft, you play. It might also have controls such as ‘sensitivity’ and ‘direction’ to suit your playing style.
If you need any help choosing a wah pedal, using one or just getting a greater understanding of the effect in general, get in touch with the teachers at The American Guitar Academy!
Alex
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