Not a stupid question.
Hz is short for Hertz which is the range of frequencies in the audio spectrum. There is no Hz selection available on the Tone, Bass and Treble virtual knobs.
The Tone should react the same way the tone control would on a given pedal. It has a set upper and lower frequency and the knob allows you to sweep that range of frequencies.
The Bass and Treble virtual knobs allow you to adjust the level (decibels - dB) of a fixed lower and upper frequency.
One that you didn't mention is the Mid Freq and Mid (dB) controls. These work together, you select the frequency with the Mid Freq knob and boost or cut the level (dB) of that frequency with the Mid knob. This is one of the most effective drive block shaping parameters.
The Low Cut and High Cut give you the option of selecting which frequencies you don't want to hear in the drive. If you want it boomy, keep the Low Cut in the 100Hz range. If you want a thinner, focused sound, set the Low Cut to around 500Hz. This means no frequency lower than 100Hz or 500Hz will be heard. Same applies to the High Cut, the higher the frequency, the more fizzy or harsher the drive can sound. Set it below 2000Hz and it will typically mellow out the drive. Set it above 8000Hz and get a fizzy, cutting drive. The High Cut does not allow any frequency higher than the set frequency to be heard. These controls are crucial in determining the core tone and feel of the drive.
Each drive block will react differently to the same settings.
Hope this helps.
