Music and audio production

I've got an unusual problem. Previously I would have asked Reddit, but screw them. Please let me know if this isn't an appropriate usage of Lemmy or this... Sub-Lemmy? Anyway I've got an XDJ-RR that originally had been connected directly to our Sony receiver via RCA jacks on both devices. Audio was really good and it might clip if the levels were pushed to the extreme on the decks, but was controllable. Now we've connected the decks to an M-Audio Air 192 6 and run the audio through the computer using the XLR jacks on both devices. Now every sound from the decks wants to clip and the audio interface level meters are showing clipping. I've got the input turned all the way down to 1 on the M-Audio interface and we have to keep the master on the decks well more than halfway to negative infinity. The master level meters on the decks barely register. Some things I'm considering:

1. The RCA outputs on the decks run through a compressor for the basic removed while the XLR outs are raw and I'm expected to know how to deal with it.
2. My XLR cables are too low resistance. I bought these years ago for microphone recording. They're Mogami neglex 2549 microphone cables.
3. Either the XDJ-RR or M-Audio Air 192 6 are defective.
4. There's a setting on the computer I could find to turn down the input gains aside from the the knobs provided on the M-Audio Air.
5. ???

Some more Notes: I'm using QJackCtl with Carla on the computer. Mostly we just patch the inputs to the outputs of the audio interface to play, but will also patch into OBS Studio for twitch streaming or Ardour for recording. Even though we keep the input gains pegged at the bottom, the main output knob is kept maxed out. Turning it down didn't help with the clipping but brought the ouptut levels down unnecessarily.