Frequency response is great, relatively flat over a wide range and the bass is tight without being boomy. Sound stage is quite good. Certainly better than most

Frequency response is great, relatively flat over a wide range and the bass is tight without being boomy. Sound stage is quite good. Certainly better than most inexpensive headphones. However, it isn't as articulate as more expensive wired headphones, which may be a function of practical power constraints in a battery-powered device (there is a reason you need an external amplifier for some of those). It could definitely be used for real audio work, with caveats. I think it would be similar to mixing with the venerable (and uncomfortable) Sony MDR-7506, which significantly outperforms its price range and also has a pretty flat frequency response but suffers from reduced articulation. If you are accustomed to using expensive high-impedance headphones you would notice the difference in detail but, like with the MDR-7506, it is good enough for most purposes. tl;dr: great for casual use, even for people picky about audio quality, and quite usable for most professional purposes though not up to the same standard. That aside, very comfortable and you can use them for conference call marathons that greatly exceed the battery life of normal AirPods.