At the risk of getting in the way of someone competent, here are some thoughts:
- Are the pi hats dacs/amps any good? (I’m not a audiophile, so it does not have to be perfect)
Can’t comment on the amps but the DACs are good, depending upon expectations. I recycled a Musical Fidelity V-DAC2 because the HiFiBerry DAC+ Pro sounded better.
- Do I need both a dac and a Amp or do all pi hats include a dac?
No, you’d need a DAC, which then feeds some sort of amp(HAT or off-board) and thence the speakers.
- What is a digi
This is a type of HAT that provides a clean output to an off-board DAC. Does no processing, other than to reclick the outgoing signal (of whatever sort) so that digital jitter is reduced. Timing is all, when dealing with digital sound, so the cleaner the signal, the better the sound.
- When using a amp most seem to be 2.0 what if I want to connect a bass speaker how would I solve that?
AV receivers can do this, most stereo amps can’t. Allo, a supplier found in the Volumio space, have a 2.1 DAC that separates out the appropriate frequencies that then need amplifying. IQaudio and HiFiBerry also have the sorts of HAT needed.
I should point out that most subs are active, and therefore don’t need additional amplification, so a stereo amp plus an active sub, all fed from an Allo Piano2.1 DAC, would do what you want.
If your bass speaker is simply a driver without amplification, i.e. passive, then I’d have to say I don’t know what would be best