The Best! Largely linear! For musicians on the go!

To I needed a headset on the iPad to play music on the go (Nano Studio, Korg apps Mastering Final Touch). So I looked for a possible small and lightweight headphones of my Studio Headphones Audio Technica ATH-M40fs comes closest, ie as far as possible linear and sound scattering. No pressure PA bass carrot and no hifi Schönfärber!
For me the Sennheiser PX 200-II has clearly won i!
Here is my comparison structure. As sound material I only uncompressed FLAC (24bit, 96kHz) used (rock, electro, classical)

- My Refezenz: Audio Technica ATH-M40fs
Linear uncolored sound with distinct mids, very good resolution, good space, depths are dry and well reproduced down to the lower frequency range.

- Sony DRV150IPB
No bass, midrange and treble particularly subdued. Sound affects dull and undifferentiated.

- Bose AE2i
Typical Bose hi-fi sound, deep well to dissolve, treble emphasized good spatiality.

- Bose OE2
Overemphasized lows but far down rich, poor space, typical Bose hi-fi sound.

- Sennheiser HD 219S
Good balanced sound, but with the typical hi-tub frequency response. good bass, but not deep down sufficiently.

- Denon AH-D310R
Overemphasized bass, dull middle, lower heights hissing emphasized.

The winner: Sennheiser PX 200-II i Headphones (115 dB)
Very good balanced sound, largely linear, basses, even if not profoundly down-reaching and not entirely without distortion. Lively sound, differentiated, and with good location. Due to the size it is extremely amazing brings out what Sennheiser here to sound.
Negatives: Optically not my case, very thin cables, connectors not angled, delicate structure with doubts about longevity.