I have a very sensitive ear. Sometimes my speakers produce a faint but high-pitched noise. This is driving me CRAZY. I wiggle the connector jack, hear a lot of pops, cracks, buzzes and whizzes, but nothing happens. What could be the source of that noise?
What kind of Amp do you have?
If it’s digital (class D-H), it might have bad filtering, leading to audible harmonics.
I have NO idea of what kind of amp I have. It has a sub-woofer, where the speakers come from. It has an acceptable sound quality, actually… Here is a picture of it: http://2.bp.blogspot.com/-IXTTCRuxUSk/UA4QrCOY6cI/AAAAAAAABro/mhiLFHM5v3g/s1600/ELG-0008_01.jpeg
Is tehre a way to fix the bad filtering?
quick update: If I turn the AC off the sound stops. Is the problem on my speakers or on the wiring?
Are those three speakers connected to anything else? Does the woofer contain some sort of music source, or are all three connected to a component amplifier?
Ah, the AC unit. It’s probably the compressor motor in the AC that’s creating the problem.
There is a cable between my computer (music source) and the sub woofers, ne cable going to each speaker and a power cord connected to the woofer. That’s it.
if the speakers are on and the cable unplugged from the computer is the sound still there?
My computer speakers will periodically emit a high pitched noise. In my case I found it to be my Blackberry, which periodically tells the cell phone towers “Hey, here I am!” combined with some really crappy shielding on the speaker wires.
My guess would be the AC is causing some electromagnetic interference that is picked up by the wire from the computer to the subwoofer.
Computers are notorious for having noise on audio outputs. Most are fine, but a substantial minority are not. Sometimes it can depend on what else you have plugged into the computer, such as USB or (back in the day) CardBus/PCMCIA cards.
First, try unplugging the computer from the speakers. Does the sound go away?
If so, try plugging the speakers into some other audio source (e.g., your phone’s headphone output). Still get the same noise? If so, most likely the problem is either the speakers themselves, or your environment (possibly exacerbated by bad cables).
Most likely is the computer. Next most likely is the speakers.
He said it stops when the AC is turned off. I suspect EMI, like another poster mentioned. About all you can do about that is move the computer/speakers farther away from the source of the problem.
So what a speaker does is take incoming electrical waves and vibrate in relation to the size and frequency of the waves to generate the sound. Fast waves are high-pitched sounds and slower waves are low-pitched, and the electrical signals that generate that motion are essentially the same as the sound waves.
But, electrical interference can come from many sources. If you’ve got voltage running on the equipment ground (the third prong on your power cable) or phased voltage on the neutral, it can affect your amplifier and get odd buzzing or whistling into the sound, and the two things that most frequently generate voltage in places it shouldn’t be are dimmers and compressors. Cooling units use compressors and of course dimmers are usually for lights. Computers are also notorious for generating buzz from the AC/DC transformers or the fans they use. Any one of these things can generate odd voltage harmonics that can get into your amplifier, and the amp and speaker don’t know those aren’t intentional, they just reproduce the waves that they receive, so you get an annoying noise.
The only solution in these cases is to isolate your power source for your amp from the device causing the interference. Depending on your power grid structure, this may mean putting the amp and speaker on a different circuit breaker from the device causing the problem. A simpler solution would be to purchase a battery backup unit that actually charges the battery and then provides power from the battery rather than directly from the wall, and run your speaker off of that - alternatively there are optical isolators that can eliminate a lot of interference by converting the waves to light and then back to electricity again.
That said, it’s a different story if the interference is caused by electromagnetic waves such as those generated by phones, television, radio, microwaves, sunspots, etc. In that case, the issue is the unprotected speaker wires. Most home speaker wires are just two piece of copper running together, and the signal travels up one side and down the other. As such, they work very much like an antenna and depending on length and exposure to the signals, can pick up EM waves and turn them into electrical interference. This is more likely if the annoying noise fluctuates and changes a lot; less likely if it’s constant and always the same. The solution here is a bit more complex and depends on the equipment but involves one of many methods of protecting the wires, including shielding, twisted pair wires, or balanced cables.
No. It actually gets louder.
Ground lift(no ground) or reverse polarity(reversed wires) on you receptical, or a receptical in the series…I have this same issue on things…
My box is spaghetti and needs over haul, i get phantom shocks on stuff. :rolleyes:
Yes, a clear case of interference from the AC. It’s FM radio that picks up the crud in my house, and I’ve had to fit noise suppressors to all the CFL and LED light bulbs, and the central heating pump.
It’s easier to try and reduce the noise radiating from the aggressor (AC) than it is to shield the victim (amp). Often the local aggressor noise isn’t too bad, it’s when the noise is conducted back down the mains wiring that it causes problems. A quick and easy thing to try is to clamp some ferrite common-mode chokes over the AC mains lead, as close to the AC unit as possible. Fitting too many won’t do any harm, and spread your bets by fitting a range of sizes. They just snap over the mains cord, so no exposure to live wires involved in the fitting.
If the ferrite chokes aren’t a complete cure, then fitting a power line filter to the AC should do the job. The filter should be appropriately rated for the AC, it should be earthed (grounded), and as the consequences of getting it wrong could be dangerous, it should be fitted by a qualified electrician.