I needed some speakers for my Macbook so we could watch films when we travel. Having read the reviews on here I sent of for some and two days later they arrived. I plugged them in and and they lit up and looked good, sat back to listen to some music and.....nothing! Tried the other USB port - same lights no sound! Damn! Got a duff pair!
Checked the instructions that came with them but no help there so got in touch with Apple support who told me what I needed to do. Go to System Preferences, select 'Sound', select 'Output', and with the speakers plugged in, select 'USB Audio Device'. Instant success! You only have to do that the first time after which the system recognises the speakers each time they are plugged in.
The sound quality is amazing and the volume sufficient to play to a crowded room. For the price I doubt they could be beaten for performance or portability, but more comprehensive instructions about using them on various systems would be helpful. Would totally recommend them.