digital vertical resolution / vertical sensitivity

hey,

i'm looking for an oscilloscope for audio applications, preferably digital, so i'm not looking for a huge bandwidth

so i'm looking at the instek gds-806s and similar models,

anyhoo, i have a question about the vertical resolution

it states the vartical resolution is 8 bit, and the vertical sensitivity is 2mV/Div to 5 V/Div

my question is where typically is the DAC located?

is it after the vertical sensitivity switch in which case at 2 mV / div i would expect a resolution of

(2mV / DIV )* (no of div) / 2^8 = 0.008 mV * no of div = 0.08 mv with

similarly at 5 V /div i would expect resolution to be

or is the DAC located before the vertical sensitivty in which case the resolution is always the same regardless of vertical resolution setting?

i read that for audio purposes, 16 bit minimum is necessary. Is this true?

also if anyone could recommend a decent oscope for audio purposes please let me know. i'd consider a PC / soundcard unit but would rather a stand alone digital unit.

Thanks

Tom