Top positive review
Very good overall earphones
Reviewed in Australia on 11 January 2020
-Sound quality: great for their size. if you're looking for sound challenging your favourite high-end-over-ear headphones for this size and price you won't find them on the market- I'm not aware of them in any case. For these earphones it's essential to get Captune, the Sennheiser app and apply a custom EQ through soundcheck (very easy) in order to get all the juice out of them (that's why you got a Sennheiser, after all)
Same applies to my over ear PCX550. Sennheiser headphones will sound flat out the box. It stays flat if playing from your itunes app for instance and bypassing the EQ. Playing from the itunes app they also produce sound artifacts (clicks and hisses) when trying to reproduce rich, dense sounds, like and orchestra or the lower end of the piano. For this reason i give it 4 stars.
-Fit: comes with four sizes of tips and three pairs of fins with varying sizes and shapes. Very important to find the perfect combination for you: Sound quality really shoots up when the tip gets that seal of the good fit with your ear canal. If you're using the right fins for you they will stay put, you just need to slightly turn and push the fins against the curved ridge of your ear behind the ear canal for a secure fit. While jogging I prefer to use the clip provided to fasten the cable to the back of my t-shirt and prevent the cable's movement and pull from dislodging the fins.
-BT: solid, stable, reliable BT, way better than similar earphones from other brands.
I recommend this product, great sound quality to size ratio but only if you use the Captune app, which is its main limitation as well.