A wah pedal alternately boosts and weakens certain frequencies in the sound of your guitar, making it sound as if it’s actually saying ‘wah-wah-wah’. The moment the effect is applied and the speed of the effect can be accurately timed with your foot.
Iconic Songs: From Jimi Hendrix to Dimebag Darrell
Wah pedals are used across a wide variety of genres. It's used in funk to lay down a funky groove (think Leo Nocentelli in I Just Kissed My Baby by The Meters), as well as in rock - where the wah pedal work on Voodoo Child (Slight Return) by Jimi Hendrix holds a legendary status, and even in blues for that extra layer of expression. American blues guitarist Buddy Guy is one of many players known for using a wah pedal, and famed metal guitarists like Kirk Hammett (Metallica), Dimebag Darrell (Pantera, Damage Plan) and John Petrucci (Dream Theater) even have their own signature wah pedals.
Wah Pedals: Pot-Controlled or Optical
A wah-wah pedal can be seen as a filter effect combined with an expression pedal. Generally speaking, there are two types of wah pedals. The most popular and common wah pedals are equipped with a potentiometer and can be fired up with a light tap on the pedal after which you can tilt in the preferred potentiometer setting. What's great about these kind of wah pedals is that they have a a bright, mix-punching sound; the downside of potentiometers is that they're subject to wear and will need to be replaced at some point. The second group of wah pedals are so-called optical wah pedals. Morley is one of the big names in this industry, where the wah pedals use an optical signal instead of a potentiometer, eliminating the risks of wear, dust and dirt. A potential drawback of optical wah pedals is their generally broad 'sweep' which means the effect can be less intense. The degree to which this is noticeable differs from model to model. Famous guitarists that love using an optical wah effect include Steve Vai, Mark Tremonti (Creed, Alter Bridge) and Michael Amott (Arch Enemy).
Auto Wah and Cocked Wah Effects
Besides the standard wah pedals, there are several other wah effects. Popular in styles like punk, the auto-wah is a stompbox that serves as an automatic filter pedal, where the playing intensity determines the intensity of the effect. The cocked wah is another flavour of wah. It gets you the sound of a wah pedal set to one of the middle positions. A classic example of this sound is the sound that Mark Knopfler added to the intro of the Dire Straits hit, Money for Nothing.
Dunlop: Cry Baby (GCB 95), Mini and Clyde McCoy
The Dunlop Cry Baby Wah Wah pedal is without a doubt the most popular wah pedal on the market and comes in various flavours. There's the original GCB95 with a red Fasel coil; the Mini-version for guitarists with limited pedalboard space; and the Clyde McCoy model which Dunlop build using the original tools and machines they inherited from the Thomas Organ Company and Jen Electronica. Clyde McCoy-style wah pedals feature a specially-designed Halo inductor and offer a more vintage sound.