Could you please recommend to me a DAC that has usb in and preferably balanced XLR's out so I can bypass the sound card on my PC (incredibly noisy) and go straight to my new Kali active Lp6 speakers.
What did you end up buying, OP?
I have a pair of MM-6s - basically LP-6 V2s but with more inputs and with auto-standby. I can connect them to my PC via 3.5mm-2xRCA and optical SPDIF. I'm using optical SPDIF right now.
If I were to buy a DAC, I'd connect each speaker to DAC's balanced XLR outputs, which would effectively make them the same as LP6-V2s.
I was also thinking about the whole DSP-ADC-DAC thing, which I don't fully understand.
1. If I were to use an external DAC, the path would be:
Digital from the PC through USB into an external DAC -> external DAC converts into analog -> analog from an external DAC into the speakers -> speaker's internal ADC converts into digital -> DSP does it's thing -> speaker's internal DAC converts into analog -> sound.
I wonder how much effect an external DAC would have in that case, and what would be the difference between a cheap ~100$ one and a more expensive device.
2. Right now, I'm using my PC's SPDIF out, so the path is:
PC's internal sound card sends out an optical signal (I'm not sure what kind of conversion happens here, does the internal sound card's onboard devices do some lifting, or is it some kind of a simple translation to create optical, and then it spews out the resulting signal) -> optical signal goes right into the DSP -> DSP does it's thing -> speaker's internal DAC converts into analog -> sound.
The ADC conversion should be skipped here since the speakers are receiving an optical signal.
Should this result in good sound quality? Will the speakers sound better/worse or different/same when fed with analog from an external DAC via XLR?
The problem is that I'm new to all this and have no experience with other audio devices. I just want a good sound out of my Kalis.

I mean, they sound great, much better than my old speakers, but that's hardly a difficult bar to clear...
Also, what do you mean by "incredibly noisy"? When I connected my speakers with a 3.5mm (from the PC motherboard) - 2xRCA (to the speakers) cable, and the PC and both speakers were on the same power strip (extension cord), I got a loud noise from the speakers, as if the PC was searching for a radio station. At first, I thought my Kalis were defective. But this was the effect of a ground loop. It can be simply fixed by disconnecting the ground (yellow in my country) cable in the extension cord. This effect is not present when connecting via an optical SPDIF cable.