9. RESULTS

8.3 ADJUSTING THE OVERALL GAIN OF THE FUNCTION OUTPUT

In the original frequency response [fig 7] the full range goes from 0– 17.5��. At the moment our range goes between 2.5��– 15��. Although they both have a 17.5dB range we’re going to want to shift the overall response down by 2.5dB so that we are affecting the correct values in decibels (dB). The way we do this is to multiply the output of the filter by a scalar. To find out what this will be in linear gain we apply 10 1/.3 /0 . To be exact, our maximum gain (full treble) sits at 2.65dB so we use this 10 1/.8 /0 3 to get: -

gainShift = 10^(-2.65/20); %converts a dB shift of -2.65 to linear gain output = output * gainShift;

9. RESULTS

In this section we will look at the results obtained from the output of bigMuffToneControl() for various values of �. We test with an impulse signal in order to obtain a revealing frequency response showing exactly how the gain of the input is affected for various positions of the 100k potentiometer (�).

Figure 16. Full Bass Response Figure 17. Mid Frequency Response

Figure 18. Full Treble Response Figure 19. Tone Control Response

We observe in [fig 18] that the full treble response sits between 0−17.5��, this is synonymous with the range of the original full treble response [fig 7].