The Wah Wah pedal uses a foot control to control an EQ filter to sweep the frequency spectrum, producing the typical Wah sound. However, there are limits to the reaction time of the human foot. So if you want to experience Wah effects that react faster than humanly possible, you need an Envelope Follower also known as an Auto Wah Pedal.
The Auto Wah pedal uses the volume of the note as it moves from attack to decay to control the cutoff frequency of a filter – this is the way the Boss AW-3 operates. A variant of this uses a low frequency oscillator to control the filter and varies the sweep of frequencies with time rather than the volume of the signal – this is the method found in the Boss AW-2 Auto Wah.
Songs Featuring Auto Wah
Some well known uses of the Auto Wah effect can be found in “Going Mobile” by The Who, “Industrial Disease” by Dire Straits, and “Mysterious Ways” by U2. Bootsy Collins commonly uses the Auto Wah on Bass Guitar and Stevie Wonder applied the effect to his Clavinet on “Higher Ground.”
Top Auto Wah Pedals
Here are some Auto Wah Pedals for your consideration:
The Boss AW-3 Dynamic Wah is by far the most popular pedal in the auto-wah category. It combines classic Auto Wah effects, Dynamic Wah effects, and a Humanizer effect that simulates a human voice producing vowel sounds. It has separate inputs for Guitar and Bass to optimize the effect for the frequency range. You can even attach the AW-3 to an optional expression pedal to control the Wah effect with a traditional foot pedal.
The Electro Harmonix Riddle Q Balls Envelope Filter for Guitar gives you ultimate control over the filter with an extremely responsive envelope follower fine-tuned for guitar frequencies, resulting in a classic funk guitar sound. The Riddle Q Balls Envelope filter includes switchable analog distortion, optional expression pedal control over the Wah filter, selectable Low Pass, Band Pass, and High Pass filters, and control over filter sweep.