I have a project to design an audio equalizer circuit with the following specifications.
- Bass band, center frequency = 180 hz, quality factor =0.7, range of adjustable gain 0.4-8
- Midrange band, center frequency = 1 khz, quality factor =0.7, range of adjustable gain 0.2-4
- Treble band, center frequency = 5.5 khz, quality factor =0.7, range of adjustable gain 0.1-2
I did the calculations to satisfy the center frequency and quality factors, but I am not understanding the range of adjustable gain.
I only have 6- LM741 op amps (I understand the 741 is vintage, it is all I have, I'm just a college student. Trying to make it.) I don't understand where to fit my potentiometers.
Initially I thought I could place a variable gain inverting amplifier after each filter, but I then thought I would need a summing amplifier to combine the inverted outputs and that would be one two many op amps. Any help or advice would be greatly appreciated.