Anyone Have Experience with Dual Parametric EQs?

[bowthing]

I designed a prototype of a sweepable semi-parametric eq, and wondered if anyone has ever tried this in a dual preamp configuration (one for each pickup). Looking to hear your experience. It seems like it might work pretty well, since the phase shifts are much less than a resonant low pass filter. The circuit I am trying is similar to what is on Mesa amps (with 3 or 5 of them). I reduced the boost and cut to around 12dB, and set the sweep from approx. 180-1800 Hz. I'm also curious if anyone has tried using a higher sweep range with a lower sweep range. This is a simulation that shows the shape of the curve at maximum boost (maximum cut is an inverted copy).

Appreciate any thoughts.

 

[Ach]

I have modded my Ibanez to have four controls: highs, lows, two sweepable mids (EMG BTS, EMG VMC x2). The set up is very versatile.
I have also tried wiring each pickup with individual 3band preamp with a sweepable mids, didn’t like this set-up, something really weird happens with the phases there when both pickups are on, effectivelly making the EQ controls significantly less responsive.

 

[Snert]

Anyone with an outboard PEQ you can easily simulate this one pickup at a time by soloing that pickup and sending it out flat.

I'm not sure that I'd find it useful, but others may, so good luck.

since the phase shifts are much less than a resonant low pass filter.

Phase shift in a broadband system isn't particularly audible. I've done a lot of research with this in my DSP cover designs in speakers.

 

[bowthing]

Anyone with an outboard PEQ you can easily simulate this one pickup at a time by soloing that pickup and sending it out flat.

I'm not sure that I'd find it useful, but others may, so good luck.

Phase shift in a broadband system isn't particularly audible. I've done a lot of research with this in my DSP cover designs in speakers.

It's not the shift that I wonder about, it's cancellation between the two channels. With two low pass filters there is a significant dip in the total response between the cutoffs as the lower freq filter reverses phase and cancels out the other signal. As the out of phase signal drops off the combined signal comes back up. This should happen a lot less with signals that are ~40 degrees instead of 180?

 

[Snert]

It's not the shift that I wonder about, it's cancellation between the two channels.

You may be correct, but I'm very sceptical it's a significant issue because of the filters. It's the physical spacing that's going to be the issue with combing.

DSP cover

Correction, DSP xover or crossover.