signal clarity:
we’ll need to know what your transceiver is and how it is connected to the digirig interface.
there are different tips/tricks for connected to a fixed audio output like from the ACC jack or a variable audio output from the speaker jack.
with a fixed output, you just have to look at the computer ‘mic’ slider and options.
make sure AGC is not checked. adjust the slider until your radio software show a 1/2 to 2/3 scale on that input. that’s usually my sweet spot on any software.
on the radio itself, AGC is usually turned off for digital modes.
this prevents the radio from dialing down the rf gain when a strong station is transmitting, effectively reducing the signal of all the other signals in the same bandspace.
wsjt-x waterfall for example, you have a bunch of 'lightly colored signals and one white hot signal. the radio AGC will ‘normalize’ the rf gain on that white hot signal. this of course ‘quiets’ the weaker signals on the waterfall. sometimes to the point of no decode.
now, interference:
YES, grounding is probably the least obsessed over part of any ham station.
grounding well/properly will give all your equipment a SHORT/FAST path to ground.
this keeps the devices from trying to find a path to ground through OTHER DEVICES.
along with grounding, think ROUTING.
routing your cables, coax, and power cords in such a way that they do not cross over each other or lay parallel right on top of each other.
something as simple as a usb charger + cable/cord right next to coax/coax connector can cause RF noise on your receive.
lastly, the audio OUT of your PC into your radio.
make sure the PC sound has NO enhancements checked.
locate your RADIO ALC meter
send a test tune from the pc software like wsjt-x
while looking at your ALC meter slide up the volume slider until the ALC is in the ‘appropriate’ position.
example:
my ICOM radios produce quality audio from 1 to 3 on the ALC scale. above 3, the ‘limiter’ starts actively keeping output ‘down’. above 4/5, the human ear can hear the ‘altering’ of the audio output. so i adjust the WSJT-X output slider (power) until i get right at 3. then for me, i adjust power output from the radio itself. that’s just me. you can slide the software slider down to decrease power but that means you are sending less AUDIO to the radio. like whispering to it. i prefer to send a full audio signal to the radio and just turn the power on the radio down.
same thing, different radio:
my xiegu g90/x5105 perform well with ALC as close to ‘100’ on the meter as i can get.
that’s a few off the top of my head.
from back in psk31days, this has worked for me.

good luck
kb0wlf