Both of these headphones are actually my absolute favorites at the moment, with the Aune taking the top spot.
While the D1 sounds very direct and 'close,' the 5000 feels wider and more 'indirect,' likely due to the angled position of the drivers.
Both headphones are very comfortable, but even here, the Aune is number one. That said, the AR5000 is among the most comfortable headphones I have ever worn.
The bass on both is sensational; it feels authentically fast and punchy. However, I perceive it more physically with the 5000.
In my opinion, the D1's big weakness lies in the range between 1 to about 4 kHz, where it frequently comes across as intrusive. This cannot be fixed with EQ. The Aune, on the other hand, always reproduces this frequency range pleasantly.
In terms of treble, I see the D1 slightly ahead.
I get the slight impression of hearing more detail here.
When I consider how affordable and comfortable the Aune is, and how incredibly 'satisfying' it sounds overall, it’s easy for me to say:
for me, this is the almost perfect headphone!
It sounds pleasant and 'warm,' yet never intrusive, sluggish, or boring.
If anyone should ask me in the near future which headphones they should listen to, I would name exactly these two models.