Anyone know the frequency curve of a guitar's tone control?

[Dpoirier]

I know it's likely to be guitar-model-specific, so in my case it's a Tom Anderson drop-top on the bridge humbucker.

We play a song where I'd need to lower the tone on my guitar for a short passage, but the song's rhythm doesn't allow enough time to do it all (tone-down, play the riff, tone-up again, and resume). So ideally, I'd like to make my preset do it, controlled by an expression pedal. The thing is, rather than hunt and peck, I'd like to have a good starting point of an idea of what the frequency curve is at, say, the tone knob on half. Then it would be a simple matter of finding those curves in an EQ block and assign a controller to it. I know, use your ears and all that, but you have to admit a strating point would be nice (and my ears are shot from too much rock&roll and getting older).

I googled it, of course, but haven't found anything yet.

 

[unix-guy]

Following... I've had the same idea before.

 

[AdmiralB]

That'll almost impossible to do without some sophisticated equipment. If you know the value of the tone pot and cap, you can create a plot of the control itself pretty easily. But the impedance of the pickup also affects the circuit, and not only is that an unknown, it's frequency-dependent.

 

[GlennO]

That would be an interesting exercise: To try to create a preset where a linear expression pedal behaves like a guitar tone knob. The major variables are the pickup, the capacitor and the pot taper. Here's a plot of frequency responses at various knob settings for a couple of scenarios for those variables:

http://guitarnuts2.proboards.com/thread/7166/effect-tone-capacitors

 

[lqdsnddist]

That'll almost impossible to do without some sophisticated equipment. If you know the value of the tone pot and cap, you can create a plot of the control itself pretty easily. But the impedance of the pickup also affects the circuit, and not only is that an unknown, it's frequency-dependent.

Exactly, the passive guitar electronics have a complex interaction which is hard to simulate with just an EQ. Same reason you can lose treble when rolling back a volume pot, but simply lowering the level in the Axe doesn’t have the same tonal interactions.

That said, I think you could do it sonically close enough with some EQ, or, it’s pretty easy to build a passive pickup simulator box, which you can dial in to have a given tone and volume pot settings, so then just step on it and it sounds pretty darn similar to adjusting on the guitar itself.

 

[MSS]

Try a high cut.

 

[Roland]

What we’re looking at in the graph is the resonant peak, which changes depending on lots of variables: the tone pot value and where it’s set to, the capacitor, pickup inductance, resistance and capacitance in the treble bleed circuit, volume setting, and cable resistance and capacitance. That’s just for starters.

I’d start from some where different. First I’d try palm muting the passage, because if that works then there’s no reason for anything more complicated. If that doesn’t work then I’d use filter block set to low pass, with a 6dB volume drop. Start at about 2k and wind the frequency down until it has the desired effect. My guess is that you’re looking for something around 1k. You need to test this in the band context at rehearsal because it will sound very different at home

 

[Bakerman]

Try a tone match: tone at 10 for local, lower setting for reference.

Pedal can fade between TM & shunt using a mixer. Parking it midway probably won't sound exactly like some other tone setting between reference & 10, but I'm assuming you just want a quick smooth fade from 10 to the match.

Playing a few chords works well enough for the match. Some music (basically anything) through a phone near the pickup works even better. Use the same clip and phone placement (easiest with guitar face up) for both match steps.

4 chords:

Song clip from phone: