Periodically a "thump", "thump" and a "crackle" or two from the speakers. Probably one or both of our fridge/freezers or the central heating going on/off. Can't do without any of them at the moment so the question is, what to do about it? All searches for filters on the net *[email protected]: up RF filters which is not the sort of interference which needs sorting - or is it? Any electricians out there with a bit of advice.
You could consider an Uninterruptible Power Supply which will "smooth out" the power to your PC and also give a power supply to your PC so that it can be shut down properly in the event of a power cut on the grid.
It's very unusual for fridges etc to have that effect. Normally, the smoothing circuits in the pc take out any small spikes that they may cause (as do Hi fi amps). Sure it's not a problem with the speakers themselves or the wiring/plugs?
Try wrapping the speaker leads (which are probably acting as the antenna for the interference) around a ferrite core a few times, physically just before they enter the speaker/amplifier unit. This might get rid of it.
Thanks anskyber and olbeefer2. Not sure is the keyword, as this sort of problem is not easy to track down. I have checked all the connections etc. The px for the speaker setup is different from the PC (which is through an anti-surge block) so I have just this minute run an extension cable from another room to power the speakers to see if that has any effect. I did a lot of LP to CD work a short while ago and none of this shows up on the "burnt" results so it would appear to be just the speakers and it's associated mains.
On the back of the speaker amp there is a little slider switch marked 5-1/6-1 and 5-1/6-1 Upmix. Although unlikely to be related to the interference problem, any idea what they mean? It was on the 5-1/6-1 setting. All connections are correct.
I suppose, logically, it could be some "noise" coming from my PC (PCI sound card Audigy2). I am on the point of getting another sound card for a spare PC so substitution will narrow it all down a bit. Thanks all for giving it some thought for me.