The Sony Smart B-Trainer is, in one word, heavy. At 43g, the earphones are over three times the weight of some of the other sets reviewed here.
It is so hefty because it is packed full of features. There is a heart rate sensor, inbuilt storage for music and GPS. There are even additional sensors like a barometer, accelerometer, gyroscope and compass.
But I am not sure if the best place for such features should be in a pair of earphones, especially if the trade-off is all that extra weight. There are plenty of other fitness wearables, such as watches, that have the same functions. They are arguably more convenient to use as wearing them is less obtrusive.
Personally, I found the chunky size of the Smart B-Trainer earphones a major turn-off.
After a few minutes of wear, I began to feel them tugging at my ears whenever I moved, although they did not loosen or dislodge. In fact, they stayed in place quite firmly throughout the whole routine.
IN THE BOX: One set of silicone ear pieces, one set of underwater ear pieces, carrying case, heart rate sensor adjustment cover, adjustment band and USB cradle
BATTERY: About six hours of audio playback with GPS disabled and Bluetooth enabled. Charging time is about 1.5 hours.
FREQUENCY RANGE: 20 Hz to 20 kHz
BATTERY LIFE: 3/5
VALUE FOR MONEY: 3/5
However, because they had a tendency to bounce up and down with every footfall, the music volume likewise jounced with my steps.
Also, because of the movement, the heart rate sensor that is tucked into the right earpiece had trouble tracking my heart rate accurately. I heard a constant stream of "no heart rate sensor signal" and "heart rate sensor ready" during my short run.
Music-wise though, the audio quality is decent, with a pleasing clarity and a well-rounded balance of treble and bass. It will be more than enough to get you through any workout.
The Smart B-Trainer has enough space to store about 3,900 songs in MP3 format. It does not have Spotify integration, so for people like me who use Spotify as their main source of music, this is probably not the set to buy.
This set is great, though, for runners who do not want the hassle of strapping a phone to their arm or carrying it in a pocket. With its amazing array of features, the Smart B-Trainer really is an all-in-one set for the road.