Now let's take a look at what the frequency response curves really look
like. So here again is the, we reduced the
whole complex pickup and tone volume control circuit to this.
And here is the expression we found for the output.
So what I did is, I just put in typical values that you would, say look up for a
typical A telecaster of tone and volume control pot resistances and the size of
the capacitor one would use and and then wrote a simple program to compute the
frequency response or what I really have is just, I've taken this factor which is
a function of frequency. If you go back you know, everything,
there are j omegas and zt. And z pickup has a bunch of frequency
factors in it. And so I can write a, you could write an
Excel program or a MATLAB A program to compute this.
And then what I plot is the magnitude of this factor.
So I'm just going to say G is one. Let's say the volume's turned all the way
up. And I'm plotting this factor as a
function of the resistance. In the tone control circuit.
So that's the variable, it's this resistor.
So, it's not very interesting to look at how things change as a function of, of G.
It's just the whole, the whole frequency response group moves up and down.
there's no change with frequency. But as I change RT, the resistor in the
tone control circuit, the frequency response changes.
And it changes in this way. So when RT is very small.
Relatively small, than the high frequencies are reduced.
And so this is like the base setting, so this is the low the low setting on your
tone control pot. The high frequencies are cutout and the
base frequencies are, are, are still present.
So that makes it sound, have a much more base-y.
Kind of tone. And then as I increase, and I've
increased by factors of two here, as you increase rt, you see that as it gets
large, the frequency response approaches something that's relatively flat.
Well, given the fact that you're hearing increases as frequency goes up, your
hearing acuity increases, and the pickup actually.
The output of the pickup is going to go up a little bit as frequency increases.
the net effect is that you're going to hear this as a very troubly kind of
sound. So so anyway, there you have it.
There's we went all the way from. A looking at the, the collection of wires
inside your telecaster. To figuring out the equivalent circuit to
working out the details of that and this is exactly what the frequency response of
such a circuit would do, okay?
Robert ClarkProvost and Senior Vice President for Research and Professor
Mark BockoDistinguished Professor and Chair
