If I were to build a 10 band EQ similar to this one:
Graphic Equalizer Circuit for 10 Frequency Bands
how would I make it a 20 band circuit? Is it just a matter of adding more of the same IC sections and components or is there more to it? I've looked around and don't seem to find a lot of info on building anything more than the 10 band EQ shown. I'm sure it is probably overkill but it is just something I want to try.
Any help would be appreciated.
Graphic Equalizer Circuit for 10 Frequency Bands
how would I make it a 20 band circuit? Is it just a matter of adding more of the same IC sections and components or is there more to it? I've looked around and don't seem to find a lot of info on building anything more than the 10 band EQ shown. I'm sure it is probably overkill but it is just something I want to try.
Any help would be appreciated.
Yes, you will parallel more filters. The "more to it" part is having to calculate the passive component values for the extra filters.
Would you happen to know where I could find the formulas for the needed calculations? This is the part I am stuck on.
Hi
It may be not so easy to add more filters. You may know what width of band all of these filters are. If its 6db/oct then changing some another close freq filter may also make changes with another - just they will so close each other. To make true graphic multiband eq will be better idea to find 12 or 18 or even 24 db/oct eq. You need band stop/notch filters to be not close enough to make changes in neighbor frequencies. For example there pot sliders: 32, 45, 60 Hz... then 45 can make changes in both 32 and 60 Hz. This will be really unwanted thing.
Cheers
It may be not so easy to add more filters. You may know what width of band all of these filters are. If its 6db/oct then changing some another close freq filter may also make changes with another - just they will so close each other. To make true graphic multiband eq will be better idea to find 12 or 18 or even 24 db/oct eq. You need band stop/notch filters to be not close enough to make changes in neighbor frequencies. For example there pot sliders: 32, 45, 60 Hz... then 45 can make changes in both 32 and 60 Hz. This will be really unwanted thing.
Cheers
Those opamps are known as Gyrators. This calculator should help. Worked great when I re-tuned the bottom 2 stages of a 5 band graphic EQ in a Technics receiver. 80 and 320 Hz was ridiculous. 25 and 180 Hz suits me better.
Guitar Pedals: Gyrator Filter Calculator
G²
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