The sound quality is exceptional, and they're put together well. My only issue is that I want them to be louder! They max out at a good listening volume, but some times you want to BUMP, and these can't do that.
I'll try with an amp and see if the volume issue is limited to the Bluetooth function.
Update: I wired these to my XDUOO DAC/Amp and they didn't get much louder, they simply sounded distorted at high volume.
MigidymikeAre you sure that you're using the headphones on full volume? It took me a while to figure out that the default volume setting on the headphones themselves is about 50% volume & it returns to that default setting every time you turn them off. The volume on the headphones & your source device are controlled separately.
They get pretty loud once you realize this.