Technically, that is.

Re: What does a wah-wah pedal actually do?

Check out this entry from wikipedia.com .

Regards,

Brad Weber

Re: What does a wah-wah pedal actually do?

Well, if we’re just going to google this, I can do better:
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“A wah wah pedal is essentially a band pass filter with a resonant, variable center frequency. Rocking the pedal sweeps a contact across a potentiometer with a semi-logarithmic taper, which varies the voltage feeding the ground side of a capacitor to make the capacitor ‘appear’ variable to the rest of the circuit.1 This variable capacitance changes the resonant frequency of the circuit, and sweeping the resonant frequency combined with the filtered signal from the guitar makes that nifty ‘wahhh’ sound come out of your amplifier.

“When the pedal is flat (i.e. parallel to the ground), the filter’s center and resonant frequencies are relatively high, and the sound produced is thin, and biased towards the treble. Depressing the pedal toward the heel lowers the center frequency of the band pass filter, drops the resonant frequency, and makes the guitar sound more ‘thick’, although most of the bass tone from the guitar is still cut out.”
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Seems to be a bias toward the guitar in both articles. The wah-wah pedal was commonly used on the Rhodes as well.

Anyway, I’m trying to determine how the effect can be got on an analog synthesizer.

Re: What does a wah-wah pedal actually do?

The short answer is with a band-pass filter, if it has one. The thing is you really want to mix some unfiltered sound in as well if you’re after a more authentic simulation of various different pedals.

If the synth in question can layer sounds or has two filters that can be run in parallel (some VA synths have this) it’s pretty easy to do. Sweeping one filter set to band-pass mode with the mod wheel/pedal etc should do the trick.

If you have a specific analog synth in mind, a more definitive answer can be forthcoming (but I may be away for a few days - though other regulars here can otherwise tell you).

Re: What does a wah-wah pedal actually do?

Thanks.

I’m not actually thinking in terms of an authentic simulation, just a general approximation of the effect--in other words, I’m using the term “wah wah” more broadly. I’m also thinking of it wah-wah-ing automatically (on a basic MiniMoog-type analog, virtual analog, or digital synthesizer with more-or-less equivalent components), rather than the player having to push a pedal back and forth or a modulation wheel back and forth.

Re: What does a wah-wah pedal actually do?

This is what Jim Aiken says on page fifty of the August 2008 issue of Keyboard:

“....we can modulate the cutoff frequency of a filter, producing a ‘wah-wah’ effect.”
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On the same page he uses an illustration I’d been using on the Internet for years--in nearly the same words--, and it really seems to me he must have got it from me. (Aiken’s apparent quoting of me in italics.) This is off topic, yes, but it struck me:

“....when the oscillations are slower than twenty times per second, if we listen to the signal, we’ll hear it as a series of separate events, like the buzzing sound you’d get by sticking a playing card between the spokes of a bicycle.”

Re: What does a wah-wah pedal actually do?

Here is the Grove Dictionary of Music “wa wa” entry:

”An onomatopoeic term derived from the sound created by the regular boost and cut of treble frequencies. It is applied to devices which produce this effect, notably the Harmon mute for the trumpet and trombone (see Mute, §2(ii)(c)), and to a signal processor unit, generally operated by means of a foot pedal.”