Speakers 'thumping' - faulty electrics?

[ACOperson]

Hi all, I'm a heating engineer with only basic knowledge of domestic electrics (not part P yet), and I have a question for any professionals on the forum.

I recently bought a surround sound package for my PC (Logitech Z-5500 digital), comprising of 5 small satellite speakers and a large and quite powerful subwoofer unit. It seemed to be working fine. I then noticed an occasional thumping noise from the system. I realised that the noise only occurs when electrics within the house I am staying in are switched on or off, eg lights, plug sockets CH pump etc.

The house has quite an old electrical system, I'd say 30 years +, and I've noticed some quite dodgy work since living here (eg electric shower run off of lighting circuit), and it has an old style consumer unit with large black plastic fuse housings. Could this problem with the speakers have something to do with the electrics in the house?

If so, would having the house properly re-wired sort the problem out?

Thanks in advance.

 

[andy]

are the speaker cables run close to any mains wiring?

 

[HDRW]

The house cabling shouldn't affect the speakers unless the cables are running close and it's picking up noise by induction.

It's much more likely that the power supply for the speakers (assuming they are powered?) is letting glitches though from the mains, which are then being emitted as sound. Try putting in some filtering (maybe start with a clip-on ferrite ring on the power lead) to see if that helps.

Of course, a decent power supply design for the speakers should mean that incoming noise isn't passed through, but these days decent design is rare on this sort of thing

Cheers,

Howard

 

[ACOperson]

The subwoofer/amplifier is connected to the mains, and the speakers in turn are each connected to the amplifier. The speakers each get their power from the sub.

There are some mains cables running close to some of the speaker cables, mostly ones which feed my PC's components. Some may be touching speaker cables. Would this cause the kind of noise I'm getting even when someting in the other side of the house is switched on/off?

Cheers for your replies BTW.