Coming from a cheap pair of Sony earphones, I was initially fairly impressed by these IEMs. The bass was powerful and the treble was far more detailed than I was accustomed to. However, it wasn't long before the honeymoon period ended and the shortcoming started to show.
First, the bass. There's a lot of it. I'm talking basshead level here. At first it sounded impressive, adding some nice, smooth bass to neutral tracks, giving them life and vibrancy where there was none before, however, things took a nosedive with bass heavy songs. Here the bass it's extended and wobbly, bleeding into mids and making a muddy mess of things, which brings me to my next point. The mids.
They could make a movie about these earphones and call it "Dude, where's the vocals?". The mids are recessed, not to the point where you don't hear anything but vocals have an artificial thinness to them with no body or impact.
If you'e looking for accurate vocal reproduction, I'm afraid the CX 3.00 not only misses the mark, but the entire postcode.
The highs are inoffensive and slightly muted. I really don't have much to say other than it does its job. You don't get sibilance and fatigue is not an issue.
If there's one thing this IEM does right, is comfort. Small, light and shaped in such a way that you put them on and forget about them. I have literally worn these all day without any issue. More companies should see what Sennheiser did here as an example of outstanding comfort design.
Now comes the really bad bit. In fact, it's almost unforgivable from an experienced company like Sennheiser. The cable.
At first, the cable looks and feel great! It's rubberised and slightly flattened giving it tangle resistance and reduced microphonics. However, the cable has a tendency to self destruct. The rubber coating softens after a while and then it starts to peel off after 3-4 months of use. It gets to a point where the very thin inner cable is exposed and the unit fails completely.
I returned my pair under warranty hoping it was a manufacturing error. My second pair suffered the same fate despite take precautions and using the carry case to store them when no in use.
So to sum it all up, these earphones are competent, better suited to EDM but lacking severely when it comes to vocal tracks.
Certainly much better sounding than the stock earbuds you get with your phone, and much more comfortable, but don't get too attached to them as they will fail fairly quickly due to poor cable quality.
