Top positive review
One person found this helpful
Punches above it's weight
on 22 August 2017
For it's size and weight this little speaker gives a pretty good and loud sound, although it can distort a bit at full volume. Very useful control functions too. Battery life is reasonable, although a repetitious Asian voice comes on telling you "ro batteree", once a minute would be more than enough. I haven't tried the SSD slot as this only supports rubbish formats like mp3.
A friend of mine has a much larger, heavier JML bluetooth speaker which has far richer sound, but the control options are not as good and its size and weight make it far less convenient to carry around, particularly when size and weight are and issue. The M4 is very small and light and is therefore ideal for taking hiking, camping or flying.
It's unfortunate that the charging connector is mini-B instead of the micro-B that most smartphones have, meaning you have to carry an extra lead.