Cracling sound coming from speakers

Page 2 - Seeking answers? Join the Tom's Hardware community: where nearly two million members share solutions and discuss the latest tech.
Toggle sidebar Toggle sidebar
check your flat for old magntic cfl ballists. the do make a large field when they come on. if your flat does use a lot of them...and your a renter....look into your local power company for grant and energy savings loans. a free energy audit will show the owner of the flat/apts they can be saving a lot of money by slowy replacing all the old lighting with led...with the right led unit they woint have to pay someone to change a light bulb in the unit for 10-12 years. a lot of the leds have min 30,000 hours before the led will fail. some have 100,000-120,000. a lot of led companies that sell the led version of the 2 by 2 and 2 by 4 parking lot lights have rent to own or 0 percent loans.. you repair for the lights out of the energy savings for the lights.
 

The problem with magnetic ballasts that are otherwise working properly is not the "large field", it is the starter tube that may cause intermittent arcs while trying to start up. Old tubes that have trouble reliably re-igniting on every cycle can generate a fair amount of EMI on top of their starter tube working overtime.

Anyhow, swapping magnetic ballasts won't stop the OP's amplifier from picking up AM radio and since the OP said the crackling appears to be related to street lights, those are beyond his jurisdiction to fix.
 
InvalidError is right, but it's not exactly street lights it's just outside my flat. I have taken a picture to give you a better idea...
After you talking about EMI, I just thought could all those lights be enough to generate a big enough field to disrupt my speakers?

A link to the pic here: http://img21.imageshack.us/img21/8476/imag0268pb.jpg (zoom in according to your monitor)
 
Any form of arcing, particularly the erratic arcing from a bad FL/starter/sodium/etc. arc lamp) will create broad-spectrum noise that gets readily picked up and heard/seen on improperly shielded/grounded analog sound/video devices. It requires very little power to cause audible/visible interference on susceptible devices.

Mechanical stove controls, mechanical thermostats, relay-controlled AC loads, just about any other form of mechanical switch will also cause some EMI, particularly when they start to wear out and have poorer/weaker contact more prone to arcing.
 
Well I know for a fact, that it's still daylight and the lights are off and I am not getting any noise, so it must be the arcing or emi from those lights.
Best solution to try now, is to try to move the speaker set to another room (together with the PC) and see the results...
 
Ok, now i have to wrap some audio cables around some lights(CFL as i have to hi pressure sodium and mercury vapor to try with) just to see what it does.

I assume this is just at the input as i doubt it is strong enough to get into the actual speaker wires and make noise?

I am surprised those lights would not be in a shielded box to block as much of this crap as they can. It is damn close to your computer.

I have honestly never picked this up on cables before(and i am not even careful with placing them).
 

Exceptionally severe EMI could induce enough current in "carefully laid out" output cables to produce some noise. Under normal circumstance though, an amplifier is required to make the noise audible. Since an arc lamp is a gaseous conductor, there is a magnetic field associated with it and if you wrap enough wire around it, you would at the very least get a 60Hz hum, likely with 120Hz harmonics due to the non-linear I-V curve, particularly while the line voltage is under 80V.


If you put a light inside a fully-enclosed metal box to block everything, you also block light.

Properly operating arc lamps produce fairly little EMI after they have lit up and warmed up to a point where the gas remains ionized or at least hot enough to be readily ionizable between cycles. The main benefit of electronic ballasts is that they keep the gas continuously ionized which eliminates the need to overcome breakdown voltage after initial ignition and the EMI that comes with that.
 
But I am picking up frequencies since the noise is present at when the volume knob is at minimum 0-15% and maximum 90-100%.
Not sure if this helps at all, but I've got a close up picture how the light actually looks like.

Pic URL: http://imageshack.us/f/843/imag0272k.jpg/

On a side note, InvalidError mentioned jurisdiction and he was correct, I cannot do anything to the lights because they are the property of my local Council.
 
UPDATE

I went to take the trash out, and where all the trash bins and storage facilities are - light was flickering. This gave me and idea, my noise is in the same intervals as the flickering light, and also the noise was not present when I purchased the speakers it just appeared. The light turns on at ~6PM exactly when the noise starts.

Can this be the case? Can a broken light or circuit mess with the voltage at my flat somehow?
 

It is unlikely that it messes with the voltage. What it likely does is cause EMI bursts every time the the tube strikes an arc as I have already stated, this gets picked up by your amplifier and you end up hearing it on your speakers.
 
The light was recently fixed and also my noise is gone :)

It was EMI bursts all along just as InvalidError said. Problem solved :)
 
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom