I hope this is what you're looking for (or at least close to)?
Some important notes: I can't work with the microphone (a system higher than XP is needed for that), so instead some music is used. I care more for the eq'ing - it uses just one signal tagged "musik", therefor this should work as is for live input as well.
Hit the play button to start/pause/resume the music. It may take a few seconds before music starts. Then just use the pseudo faders for eq'ing. In this demo it's six bands, but you are not limited on this. You can have as many bands as you like, with whatever frequencies you need.
To not bloat this to a full app, there are only fixed frequencies and bandwidths. They are from left to right per fader: 100 Hz, 300 Hz, 600 Hz, 1.2 kHz, 2.4 kHz and 4.8 kHz, with a narrow bandwidth each.
Range of the faders is +20 dB (top) to -20 dB (bottom). I lowered the music volume by 20 db to prevent to much clipping, when all bands are at max.
IMPORTANT: You need web audio ("advanced audio support") and webGL. I only tested on Chrome with WinXP, and that's working like a charm.