Can the 'vocal tone' effect be altered on the FX150 or is it just on/off?
If Tone is ON, the EQ controls are “tweak” controls for the Tone algorithm. Essentially, it’s a limited (+/- 6dB ) EQ that you can use to get “a bit more treble” or “a bit less mid” etc. after Tone has done its thing. When Tone is OFF, the EQ range gets bigger and acts more like a traditional EQ.