The only way I found to minimize/eliminate HISS while using high quality monitors/pro speakers is to pair them with a proper external USB Audio Card.
Those External Audio Cards receive the signal in digital form, thus free of any noise they could pick up in the process. These are decoded inside the external DAC which then feeds audio to the speakers. since this part of the signal path is analog, any interference picked up by these cables is gonna appear on the speakers, which is why the good gear usually supports BALANCED SIGNALS so that the speaker can reference the signal and weed out noises added while in-transit.
My gear is a pair of YAMAHA HS8 speakers and a YAMAHA AG06 external audio card. Both support Balanced audio so that's what I'm using regarding cables between the audio card and the speakers.
Checked out the AG06 but it has internal DSP and other things I don't really need, plus it seemed like more of an audio interface than a sound card, do you have any recommendations for balanced audio usb external cards without all of the extra stuff?
A replier said something about a brand called "Schiit Audio", but I've researched them and they only offer stuff with RCA outputs which are sadly not balanced at all.
If you're on a budget you could get the AG03 which is the same interface, but with less input channels.
Also, the DSP is totally optional on those, If you don't use it you'll bypass it totally, not coloring or changing your signal in any way.
Btw you mentioned your speakers are Mackie, right? Before buying, research if your speakers actually support balanced input (they use XLR or P2/TRS "stereo" (2 black bands) for that, because each speaker is actually receiving 2 polarity-inverted copies of the signal). If all they have are RCA inputs (mono), you're out of luck.
Hope I could help!
EDIT: I have researched your monitors and they do have all three types of input: XLR and TRS (balanced) and RCA (unbalanced). yay \o/
Now go get yourself a nice audio interface with support for balanced output and go make yourself some nice XLR cables.
The Yamaha AG03 AG06 output balanced TRS signals, but for that extra "click" factor no the monitors I have built a custom cable that is TRS on the DAC and XLR to the monitors. That way it stays put :-)
I've researched this brand and could only find devices sporting RCA outputs (like Fulla or Bifrost). You need a proper XLR balanced output (3 wires) for balanced.
In that regard, the AG06 is much cheaper than any of the offerings i'm finding from Schiit.
Those External Audio Cards receive the signal in digital form, thus free of any noise they could pick up in the process. These are decoded inside the external DAC which then feeds audio to the speakers. since this part of the signal path is analog, any interference picked up by these cables is gonna appear on the speakers, which is why the good gear usually supports BALANCED SIGNALS so that the speaker can reference the signal and weed out noises added while in-transit.
My gear is a pair of YAMAHA HS8 speakers and a YAMAHA AG06 external audio card. Both support Balanced audio so that's what I'm using regarding cables between the audio card and the speakers.