Sorry for the long post but my new sub hums & I am losing what little hair I have left... I bought a Mission FS1/AV surround speaker package from Richer Sounds yesterday. However, the subwoofer persistently hums as soon as the power is switched on. It does this regardless of whether it is connected to anything else - receiver or speakers, and regardless of whether any other equipment is on or off. I have tried different wall sockets & different rooms in the house but the hum continues as soon as the sub is switched on. Even moving the sub alone upstairs makes no difference. I have read stacks of previous threads & looked at the ground loop issue, but don't think its that as it hums consistently whatever it is connected or not connected to, & we don't have cable TV, and I have tried it with all of our cordless phones switched off just in case. The hum sound to me like it is coming from the amp/power supply inside the woofer, and not the speaker. The hum does not increase or decrease in volume when the sub or receiver volume controls are adjusted (with or without any music being played). I would have expected a minor amount of electrical sound from a sub, but would only expect to hear it if my ear was almost against the body of the sub. This hum though can be heard anywhere in a 26ft by 11ft lounge. There is no way I can leave the sub on unless I am watching a loud film or listening to loud music. Now I have heard it that is all I can focus on when I am using the system. I hope this is not what Mission meant when they say that there is "no sweet spot" with these speakers. Before anyone replies along the lines of "it hums because it doesn't know the words..." can any other Mission FS1 owners let me know whether their subs hum in a similar fashion please? My brother has the similar Denon SCAV 100 NXT setup & his sub does not hum so he leaves it on all the time. Something which strikes me as strange about this sub from Richers is that is doesn't have a normal 3 prong UK plug, instead it appears to have a 2 pin shaver type plug inside a black plasic 3 pin "Power Connections Euro Converter Plug" with the central earth pin just being a piece of black plastic. So could this be a Euro import which is not suited to such a conversion with a UK electricity supply, and there is nothing I can do other than return it for a refund? The lack of any user manuals or Mission warranty card leads me to think that this is going to be the case. So I would be grateful for any feedback from other FS1 owners as I am keen to decide how to progress this as soon as Richers are open tomorrow. Cheers, AJP.