I was a little worried, concerned because of the negative reviews here partially at Amazon, especially as the noise of the boxes.
But when I have connected with me and tried I could fortunately find no noise, whether on full blast or not. Even if I have applied my ear to the subwoofer, I could hear no hum. Perhaps there was a faulty production series in this model that is causing the hum of some. Only if my phone is right next to the speakers, there is sometimes the typical Handystörgeräusche.
For my purposes, the boxes are more than adequate and I am very satisfied. However, I am not an expert in sound quality, my video games, movies and listening to music on really well in 5.1. The rear speakers sometimes seem to me a little quiet, the audio manager they are but as loud as the front, so I think they'll just not as much driven by the respective programs.
All in all I am very satisfied and can only recommend this 5.1 system.