I may have missed it, but I don’t think anyone has mentioned what I would consider the easiest, cheapest thing OP should do: try Roon or Audirvana. Running a signal direct from a Mac to a DAC means the Mac’s internal audio "enhancers" are mucking with the output before it leaves the computer chassis. It’s a well-known issue. Audirvana, Roon, and other applications bypass this and give you a proper signal for your DAC, not some "lowest common denominator" signal designed for all possible headphones, devices, etc. Using the Mac’s USB output does not avoid this. Sign up for a free trial run; it will sound like you got a new DAC. (Paul McGowan of PS Audio has a few videos on this; the library of those is on the PS Audio website. But the gist is: see above).
Lots of other good ideas here as well. But me thinks your DAC is getting a garbage feed. I’d start there. And, of the software options, I really like Roon. If you doubt the premise, try a CD from a decent CD player/transport, run through the DAC, and compare the same track to a 16/44 file from your Mac to the same DAC. If I’m right, the CD will crush the file. If I’m wrong, they will sound more or less the same. I’ve been wrong before ... Just don’t use your Mac as the CD player in this experiment!
Disclosure statement: No affiliations with any audio companies, dealers, distributors, PC manufacturers, magazines, influencers, YouTubers, TikTok-ers, software companies, or labels. Just a hopeless gearhead who can’t sleep.
Lots of other good ideas here as well. But me thinks your DAC is getting a garbage feed. I’d start there. And, of the software options, I really like Roon. If you doubt the premise, try a CD from a decent CD player/transport, run through the DAC, and compare the same track to a 16/44 file from your Mac to the same DAC. If I’m right, the CD will crush the file. If I’m wrong, they will sound more or less the same. I’ve been wrong before ... Just don’t use your Mac as the CD player in this experiment!
Disclosure statement: No affiliations with any audio companies, dealers, distributors, PC manufacturers, magazines, influencers, YouTubers, TikTok-ers, software companies, or labels. Just a hopeless gearhead who can’t sleep.