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Post by yakkmeister on Apr 7, 2012 4:39:33 GMT -5
Hey guys!
I have been thinking over some things recently and one of those things was tone controls.
I have noticed that come guitars have much 'smoother' controls than others, that is to say that the level of adjustment is similar across the entire sweep of the pot.
That is to say, I have seen guitars that have tone controls who's sweep does nothing until the very end of it's travel and then the change is drastic. Still others make nothing but the smallest change from full-on to full-off.
I suspect this has to do with taper but I also suspect that there is more to it than that ...
What I would like to know is what effect taper truly has and what over factors contribute to these characteristics.
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Post by newey on Apr 7, 2012 5:59:29 GMT -5
Here's a very general answer to your general question . . . (I was going to provide a more specific answer, but then I remembered that 5spice doesn't do log tapers) Whatever differences you hear in tone controls can be put down to three variables: The taper of the pot, the resistance value of the pot, and the value of the capacitor used. A linear taper pot would show a straight-line response; an audio/log taper pot, as you surmise, does affect the response curve such that there's more "action" at one end of the travel than the other (reverse log taper pots (a.k.a. "anti-log") are also available for lefty use). The value of the pot also has an effects- the larger the pot's resistance value, the less of a range of travel one has. However, playing with the pot's value also affects tone- most people choose a higher-value pot for the added brightness, or a lower value for more darkness, rather than because of the change in the "smoothness" of the response. This effect is less noticeable when we're using the pot values that will produce a useable tone- 500K vs. 250KΩ, you're not going to notice a lot of difference in the pot travel. But if you were to use a pot of, say 3MΩ, all of the action would be within a very short range of travel of the knob- at some high value, it starts to function more like an on-off switch. A lower pot value gives more change over the whole length of the pot's travel, but the tone will become unacceptable (to most ears) below about 100K (unless it's an active circuit, that's a different animal entirely). The capacitor value used changes the frequency response curve as well; this is a complex interaction which depends on the pickup used as well as the other components, so I don't want to oversimplify. But, in general, changing the cap value moves the "knee" of the frequency curve. This is all easier to see graphically than to explain; we've got some diagrams around somewhere, let me root around in the basement.  |
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Post by newey on Apr 7, 2012 6:09:23 GMT -5
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Post by yakkmeister on Apr 7, 2012 9:42:31 GMT -5
I see! Wonderful explanation there - it pretty much answers my query  |
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Post by reTrEaD on Apr 7, 2012 9:53:44 GMT -5
Whatever differences you hear in tone controls can be put down to three variables: The taper of the pot, the resistance value of the pot, and the value of the capacitor used. I'd add a fourth factor: The internal inductance and resistance of the pickup(s). |
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