I received my pair of MH1a, the earphones part from the MW1 bluetooth headset package yesterday. I bought it from a taobao shop who was willing to sell the phones and bluetooth receiver parts separately. I listened to it with a generic Sennheiser 3.5mm extension cable for IEM, from a S:flo2/Arrow G4 combo. Below are my feeling:
1. Very good instrument and vocal separation. In my opinion this is the trait of any high quality earphones/speakers. The MH1a is not a high resolution earphones but because it never mix different instruments and vocal together, it gives the listener a clean, dark feeling.
2. Smooth. So far I could not find any vocal recording which I can find sibilance. The MH1a playback is like a photo you take with a DSLR with the multi-frame noise reduction turned on: it removes any noise/sibilance from the background.
1. Cables, like everyone has mentioned
2. Cannot take high volume: I think my pair of MH1a hasn't burnt in but it seems that the micro drivers in it cannot take high volume. If I listen at low volume (in mid-night quiet living room), it is an absolutely wonderful earphones. But if I turn up the volume a bit to the similar sound level I would normally listened to outdoor, it sounds "bloat". I suppose this might be why some other people think they have got a bad pair of MH1
3. Proper insertion is a must for good sound: The tips definitely play a big part of the MH1a sound tuning.