So Cyber-shot is one of Sony Ericsson's big co-branding schemes, but what's the other? Walkman, of course. As a music player, the X10 fares pretty admirably; we'll touch on the software in the next section, but from a hardware perspective, both the jack placement and the quality of the audio that the X10 produces are decent. The music was a little less punchy on the bass side of the spectrum than we'd like -- even with our Shure SE530s and triple-flange tips, both of which tend to accentuate low frequencies -- but the signal-to-noise ratio seemed superb throughout our testing. We could barely detect the presence of any electrical noise on the line; in fact, when we first plugged in, there was absolutely none. That's pretty rare for a phone.

The low-noise trend continues through to the earpiece while on calls. We were surprised at how the X10 was able to suppress line static without sacrificing volume; it was so good, in fact, that we had trouble at times figuring out whether we were still on the call when the person on the other end wasn't speaking. Likewise, the speakerphone is exceptional, both loud and clear enough to be useful for those impromptu conference calls we all have to take from time to time (or for when we're driving and we're caught without a headset). Sony Ericsson smartly placed the loudspeaker port on the side of the phone, not the bottom, so setting the phone down in any position has no ill effect on volume or usability./engadget