iPhone 4S Emitting Radio Sound Waves

ET iPhone Home

macrumors 68040
Original poster
Oct 5, 2011
3,743
465
Orange County, California USA
Guys,

I have a 4S and I was at the library and I thought I was hearing the air-conditioning system, but realize this low whistling was emitting from my 4S. The best description is it sounded like low frequency radio sound waves.

Has this happened to anyone? Anything worth investigating further? I don't have Apple Care, but still have until early November to take care of this if it needs taking care of under my warranty contract.

Thanks.
 

falterego

macrumors 6502
Dec 28, 2008
280
0
Southern California
Do you mean the phone itself is making a noise, or you have headphones on and you suspect the phone is causing interference? I've gotten headphone interference before when listening to music off my computer and have my phone next to it, but that's because I usually have cheep-o headphones that came with another cell phone to use. When I use my good headphones I have no problems.
 

ET iPhone Home

macrumors 68040
Original poster
Oct 5, 2011
3,743
465
Orange County, California USA
Do you mean the phone itself is making a noise, or you have headphones on and you suspect the phone is causing interference? I've gotten headphone interference before when listening to music off my computer and have my phone next to it, but that's because I usually have cheep-o headphones that came with another cell phone to use. When I use my good headphones I have no problems.
I have the 4S next to me on standby mode without any use of attached devices and it periodically will emit these sound waves which are very low frequency and I can hear them.

You know when you switch from one station to the next and try to get the reception clear, it's not the static noise I'm referring too, but those low frequency sound waves.
 

falterego

macrumors 6502
Dec 28, 2008
280
0
Southern California
Might be something to take it into the store for. Although the store environment can be quite noisy, so the person you work with might not hear something and send you walking. Worth a shot though if you have the time to go in for an appointment.
 

Menel

macrumors 603
Aug 4, 2011
6,202
1,057
Guys,

I have a 4S and I was at the library and I thought I was hearing the air-conditioning system, but realize this low whistling was emitting from my 4S. The best description is it sounded like low frequency radio sound waves.

Has this happened to anyone? Anything worth investigating further? I don't have Apple Care, but still have until early November to take care of this if it needs taking care of under my warranty contract.

Thanks.
Range of human hearing is roughly 20hz - 20khz, sometimes a little higher.

GSM/CDMA is 800-1900M way beyond audible hearing. The noise GSM couples onto speakers is just some of the modulation, or maybe some inrush current spikes emitting some EMI when the transmitters are activating out of sleep.

Nothing in the phone is going to be operating normally that low. Sometimes on random electronics, displays, especially CRTs, but other electronics also can hear noise. I have had to go around and hunt down the offending unit and turn it off, people think I'm crazy. We have a prototype system in our lab now, miniature embedded system with an Atom CPU and custom power supply and I can hear an annoying buzz from it. (Edit: actually it died yesterday, it decided to never power on again for one of my technicians LOL... Yea warranty it!)

Its likely inductor hum from internal power regulators. Take it to a genius bar. Its not at risk of failing anytime soon, I've seen electronics run for years in that state, but it is annoying.