dharmasteve
Headphoneus Supremus
Interesting footnote about the Bluetooth volume. I've been complaining about the M9's BT volume for a while now, and feel it's underpowered compared to other "less powerful" devices - and your comparison with the M6 suggests just that. It's also completely skewed compared to the headphone output, which means after you're done listening to BT at Volume 70, you'd better remember to switch back to 40 for headphones or you'll blow your ears. FiiO needs to take a look at the BT volume level on the M9 and hopefully fix it in firmware.
There is no doubt that Bluetooth APTX-HD volume on the M6 plays at a louder volume compared to the same volume setting on the M9, and that is with the M9 on high gain. 60 on the M6 is considerably louder than 60 on the M9 Bluetooth wise. Once the volumes are at the same adjusted listening levels there is very little difference in quality. I do suspect Bluetooth implementation is different on the M9 to the M6. The M6 being newer may be slightly improved. Hope it is a software issue and can be resolved. Anyway you are right gLer. But under direct wired IEM connection the M9 is clearly better. Don’t know how the two DAPs compare with Bluetooth headphones or Bluetooth IEMs? Anyone?