Done_Fishin

Sound & Static interfering with your Music enjoyment.

You're busy on your PC, getting some work done whilst playing your favourite pieces of music in the background, probably a little bit louder than you should be too, but what the heck, no-ones complained yet and it really is a GREAT piece of music anyway, when you suddenly realise that your favourite piece is not playing as clear as it should be!
There's something extra, a noise or audible interference coming over the audio sytem that shouldn't be there!

Sometimes the noise seems to happen as the mouse is moved, at other times it might seem that you are listening to a local cab company or cab driver talking over the radio but the sound is indistinct and fuzzy.
It may be that you realise after a while that the interference appeared after you changed over to a wireless mouse.
Listening carefully to the noise, we may be able to tell when it happens or what it is linked too.
Trying to remember when it started might also help pinpoint the cause.

When the noise is found to synchronize with mouse movement or changing over to a wireless mouse, the interference you can hear is being induced into your audio system because the electrical impulses inside your PC are not being filtered properly. It could even be direct radiation into the wiring of your speakers or "pickup" by the audio section of your amp or sound card.

Back in the 70's when I first started worked in computing, it was quite novel to see one of the more senior Engineers working in our department, arrive with a large stack of punched cards and a transistor radio, which he would place on top of a Burroughs B500 processing unit.

If you've ever seen the original "lost in space" series then you'll understand what Computers used to look like, back then, with little lights all over the front which flashed on and off indicating data being moved through the system.

The Engineer would then load the punched cards into the card reader, sit down at the Processor and load the data. Once loaded he would turn on the radio, press RUN on the console and listen to the "electronic music" being picked by the radio.
The music he was listening to was being picked up as a "radio frequency" and then the audio content was amplified and passed through to the speaker.The sound which was being heard had been cleverly programmed into the computer by some wizkid with an urge to experiment and has probably ended up being the reason why we can listen to mp3's today!
On todays level it is something akin to that tell tale sound we get on the radio or house phone when a mobile is being scanned ready to accept a call.

Of course, in the above situation, it was a desired effect (of the information travelling around the system) to cause interference that would be picked up by a radio receiver and give a reasonable if tinny musical rendition of popular tunes.
When that rendering becomes an annoyance though, it's time to find a way to stop it from happening.
The frequencies running around the modern computer have many side effects, from blocking the signals getting to a mobile phone to injecting noise on audio components which result in distorted listening.

In order to overcome that you can try using some ferrite toroids on your audio cables & speaker leads to try to kill it. This involves getting circular ferrites approx one inch diameter like these



Toroids come in different sizes, as you can see & you really need to be able to get several turns of wire (I used 5 turns in my installation) through the toroid if it is to be effective.
If you have to get jacks or connectors through the centre then you'll have to find one large enough to take the jack plus all the wiring. If you are just pushing bare wires through then you don't have to be so fussy, so long as you can push the wires through on the last turn.


The result should look like this ..

Audio out connector from the front jack of my PC




Speaker leads from my Stereo Amplifier.



Do this on all audio cables until you either have no more cables to do it on or the noise goes away.
The ferrites in my pictures are from old PC power supplies, I removed them, stripped them of whatever wiring was on them and used them to help block my system from picking up a local radio amateur when I was recording vinyl disks to HDD.
There's nothing worse than getting some idiot start blabbing away in the background when listening to music you have spent hours recording and editing.

If the above doesn't work you might need to experiment with different audio cards, possibly screened, try better cabling (possibly double screened) ... and don't forget that a good earth to your stereo might help, but it can also cause more noise if you find yourself in a 50/60Hz earth loop, which causes "HUM".
To remove hum requires isolating connections to earth on the audio cables, one by one, until you find the lead that is causing the problem. You may get away with just disconnecting the shield at one end of the cable or, since the earthing is common all around the system, remove the earth from the plug.
I would not recommend the latter since it leaves a potentially dangerous system should that particular unit be taken and used elswhere unearthed.
It's usually better (and far more preferable) to isolate the earth at just one end of the audio cable.

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