Dumb question of the day: amplifier presence controls?

[carlaz]

OK, considering how long I've been messing about with guitars, this is an insane question, :oops: but: What the heck does a presence control actually do?

I mean, I know it's to do with twiddling treble frequences of some kind, and I can hear the change when I sweep the setting from one extreme to another, but what does it actually do?  In the past, playing live and stuff, I've usually ended up just setting it to something and forgetting it, but these days I'm experimenting more with different tones in home-recording and I realized I have no real idea what this control is supposed to ... control.  (Any examples of tones with more or less "presence"?)

[maliciousteve]

Well i use presence to add more deffinition to my sound. Pushing the presence up a bit helps with playing in a live setting, makes you stand out more in a mix. But too much can sound cr@p and you'll be fighting with the hi hat

[Ratrod]

The manual for my Fender says it controls the 'very high frequencies'.

[Johnny Mac]

+1 The more you turn it up the more treble and definition you can hear. Too low and things sound muddy and rubbish. I don't how they compare from one amp maker to another though.

[dave_mc]

turning it up gradually removes an invisible blanket from over your speaker.

[HJM]

Presence usually works in an amps negative feedback loop, don't worry about hat, what this means is it is a EQ on the power amp only. Presence alters the higher frequencies in the power amp, resonance alters the lower frequencies in the power amp. Some amps voice the operation of the presence control in different frequencies, some effect the high mid others just the very high end.

[The amazing Phil]

Just out of intrest, how would you say that compare to the attack knob on a Matamp C7?

[carlaz]

Hmm, it's looking like it's hard to genericize more than " presence is likely to control some aspect of high frenquencies".  No wonder I've never got my head around it!