I asked Godin how the 2-band EQ of their A6 Ultra guitar works. They are obviously wired to the neck pickup, but it’s not obvious if they are boost/cut and what the frequency ranges are.
Here is their detailed reply. I’m sharing this in case others wonder as well.
1) The Bass and Treble controls are an active, shelving type equalizer similar to many analog tone controls (think mixers where each channel has a separate rotary bass and treble control). They have a nominal boost/cut of about +/- 10 dB.
2) We consider the 12 o’clock or centre to be the “flat” setting, although due to specific A6 voicing there is a slight mid-notch at this setting.
3) Since the equalizer is a shelving type for only bass and treble, there are really no center frequencies. The bass control is essentially a low pass filter with boost/cut. The treble is essentially a high pass filter with boost/cut. The bass control affects primarily frequencies below 400 Hz (with more emphasis on lower frequencies) and the treble affects primarily frequencies above 900 Hz (with more emphasis on higher frequencies).
Kudos to Godin for such a detailed explanation!