In-line with its colourful looks and sporty outlook, the Ultimate Ears 300vi have been "tuned for extra bass" according to Ultimate Ears. And boy, can you hear it.
The bottom-end here is big, bold and frequently boomy. This leads to a sound that's not very sophisticated or refined, but is a good partner to a workout, as we found while testing the earphones on a run while pumping-out some electro. With some music the bass seems simply ridiculous though, reducing drum and bass with a heavy bassline to an overblown dirge.
Unlike some basshead earphones, the Ultimate Ears 300vis aren't completely dominated by the bottom-end at all times - the sound's fairly warm and there's a decent amount of high-end detail. However, the high-end can also sound harsh, which becomes fatiguing before long.
As a pair of earphones to take to the gym, these meat tenderiser-like earphones are a decent choice, but for calmer environs you can get a more refined sound from the classic Sennheiser CX550s, or the Ultimate Ears 400s, one step up this range. The sound is exciting and powerful but won't please more critical or analytical ears, and isn't easy on the ears enough for day-long listening.
Aside from trying to cave-in your ear drums while you bench press away, the Ultimate Ears 300vis also double-up as a headset for your mobile phone and a remote control for your iPod. The control housing for this sits along the right bud's cable, just before it's unified with the left bud's wire.
It's comprised of three buttons and doesn't add significant weight to the earphones - although it will bash against your clothes when jogging unless you secure it with the supplied plastic shirt clip. Used with a mobile phone, the central button takes and ends calls, while the two buttons at its sides change volume. We tested the Ultimate Ears 300vis with two Android phones (not officially supported) although only for taking calls - the volume buttons didn't work. With an iPod Touch and iPhone, the remote worked exactly as expected, altering volume with the outside buttons while the central button works as a play/pause button.
The Ultimate Ears 300vi are good earphones for runners and gym fanatics thanks to their ear-hugging, microphonics-reducing design, but overblown bass and harsh treble mean they're not the best buy for the rest of us.