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Joined: Dec 2003
Posts: 886
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What kind of installation is this- home theater, whole house? What kind of sub woofer- self powered or voice coil? What is the other equipment?
-Hal
[This message has been edited by hbiss (edited 01-21-2005).]
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Joined: Oct 2001
Posts: 172
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is the sub powered from a different circuit, possibly the one that serves the fan and refrigerator? if not, could it be sharing the neutral on a multi wire circuit?
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Joined: Dec 2003
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Well, if it is a powered sub with it's own amplifier inside of it it would mean that it requires power and there is one or two unbalanced audio lines going to it. If the sub is located away from the main equipment it is usually plugged into the nearest receptacle. This can cause a ground loop through the equipment grounds and the audio cable shields assuming that everything uses 3 wire line cords.
Again I am assuming here, need more information.
-Hal
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Joined: Dec 2004
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The kind of noise you're talking about usually gets in through the amplifier.
There are two pretty common ways that kind of noise gets in.
One is through the amplifiers power supply. If that is the problem you can reduce or eliminate it using a filter on the AC line. I'm calling it a filter because "surge protector" could mean just about anything. But a "real" surge protector (one with at least 12 db per octave responce) is actually a filter. If you have one or want to get one, plug the amplifier into that and see what it does.
Another is inductive coupling. Usually this would happen in the preamplifier section of an amp. Like with the old phonographs (member those) the preamp is very sensitive. If that is the problem you might be able to hear a car's ignition come through the speakers. You might be able to test that by lighting a lighter with a piezo electric ignighter near it.
Another thing you can do is to interconnect the chassis of connected components. If it's a ground issue that will make it stop. But if it does there may be grounding issues in the building you might want to check out.
A new amp might fix it too.
Sam, San Francisco Bay Area
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Joined: Oct 2004
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An arc or spark is also a form of RFI. Try a ferrite ring on the power lead to the amp or equipment used.
SimonUK.
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