OE (on ear) i for iDevices my initial impressions is they are very good. Testing with my macbook pro using Lorde Tennis Court and Australian Chamber Orchestra (Mozart Violin Concerto #1) .
image: Sennheiser stock
The bass was really good as expected, not too bassy but still has a bit of punch, though I’m fairly sure that the Lorde album is mixed specifically with a deep bass, especially the recent album. On the classical music I notice though I need to have the volume at almost maximum to hear extra fine details in the music i.e. a breath etc. Curiously the advantage with in ear headphones is the volume doesn’t need to be as high. This makes sense because more material needs to move in over ear systems.
Just comparing with PXC 250 II (with active noise cancelling on) now it seems these M2 seem less bright the bass is more pronounced though high frequencies do get through. But I do get used to it.
A good comparison song for headphones is Stay High (feat. Hippie Sabotage) [Habits Remix] as it has good high notes frequencies with a bass background beat.
Later extended testing
Just wore them for 40 minutes continuously watching Stargate SG-1 and did find they felt a bit too warm after that time, also I needed the volume at a higher level. Starting to think that perhaps the over ear might be less warm because there may be slightly less pressure and more circulation. Testing this again and noticed that moving the headpiece a bit higher slightly off ear seems to allow for less warmth build up, but it does change the audio quality a bit, less bass.
These have a very similar sound to the MX 3.00
Frequency range: 16Hz - 22000Hz
Impedance: 18 Ω