have bought 2 units and at least my two give a clearly audible sound, regardless of whether a device is plugged in or not. Thus, it is not to be used next to the bed in the bedroom for me. The highway near bothers me because fewer windows open. Works as far as I can tell properly. 2 x 10 Nexus, Nexus 7 x 1, 1 x 5 Nexus fits charged simultaneously. The inscriptions vodefinierten I find perfect sense freed almost an impertinence. (IPad, Samsung Tab, iPhone) the user with exactly this configuration, I'd like to meet times.