Low resolution audio while playing in editor. Sending sound thru S/PDIF to an Apollo Twin interface

Anyone else experience a severe drop in audio quality depending on how/where you send your audio signal? All my SFX files are mono,16-bit, at a sample rate of 44.1kHz. My signal flow goes, PC’s optical out –> optical in on the Apollo Twin interface –> MacBook Pro. I was thinking my problem might have to do with mismatched sample rates between Unreal and the Apollo, but no matter what sample rate I choose for the Apollo, all the audio coming from Unreal sounds like bitcrushed garbage.

I get a clear signal while using a small USB headphone amp, but I’d really like to be able to use the optical out to accurately monitor and analyze audio through my MacBook.

I’m fairly new to UE4 so there may be something simple I’m overlooking. Any advice or suggestions would be warmly welcomed. Thanks!

With USB audio out it works? It has built in soundcard. Check windows’ optical soundcard driver settings, bitrate issues are there I think! (assuming it goes USB ->interface->mac, not the shorter USB->ear. In that case we haven’t narrowed things down)