HDMI cables will add up latency (because of the TV/monitor processing), some ms but perceptible if you're recording a live performance and monitoring it.
One DAC per speaker may cause time drift problems.
The best solution is use a high-quality external soundcard with studio monitors. onboard soundcards tend to have sub-par components that add up noise and have less-than-optimal frequency response. Even a Behringer UCA222 is better than the general onboard DACs.

2015-04-22 16:52 GMT-03:00 Charles Z Henry <czhenry@gmail.com>:
Build your own with some (nice, affordable) boards from Hong Kong:
http://www.yuan-jing.com/dacs-decoder


On Wed, Apr 22, 2015 at 2:33 PM, Andrew Kelley <superjoe30@gmail.com> wrote:
> I am imagining this setup:
>
> Plug a USB or HDMI cable into my computer.
> Plug the other end into a hub.
> 5 speakers and a subwoofer all plug into the hub.
> Plug the hub into a AC power outlet.
>
> So there would still be one DAC, and it would be in the hub. Is a DAC really
> that expensive? Why can't they be everywhere?
>
> On Wed, Apr 22, 2015 at 12:30 PM Paul Davis <paul@linuxaudiosystems.com>
> wrote:
>>
>> On Wed, Apr 22, 2015 at 3:10 PM, Andrew Kelley <superjoe30@gmail.com>
>> wrote:
>>>
>>> I don't understand why speakers are using the analog output cable for
>>> sound. How about, use a digital interface like HDMI or USB?
>>
>>
>> someone you need to convert from digital to analog. do you want one DAC
>> per speaker when you could have one DAC per computer?
>>
>
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> Linux-audio-dev@lists.linuxaudio.org
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