# Why do we no longer hear that dreaded cell phone interference sound anymore? **URL:** \ **Category:** Factual Questions\ **Created:** [April 17, 2017, 4:53pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636 "2017-04-17T16:53:32Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Asuka](https://avatars.discourse-cdn.com/v4/letter/a/dec6dc/32.png) [@Asuka](https://boards.straightdope.com/u/Asuka)\ **Post date:** [April 17, 2017, 4:53pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/1 "2017-04-17T16:53:32Z")
This sound When I was in high school in 2008 I still remember how whenever we watched anything on the TV mounted in the corner of the room it would pick up every single cell phone signal used in the class and thus you were hearing that noise constantly. My old PC speakers would also pick up interference when a phone was used more than 20 feet away. Now when I have a room full of friends all texting at the same time I don't hear interference from either my computer or TV speakers in the same room. The most obvious answer would be “Speakers are made now with that in mind” but that can’t be all of it can it? ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [April 17, 2017, 5:30pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/2 "2017-04-17T17:30:23Z")
There are 3 possibilities : Cell phones are using different frequencies (unlikely, frequency is scarce, the frequencies that were interfering in 2008 must be the same). The _modulation_ has been improved, but it should still produce audible interference. The equipment you are using now is shielded better. It is straightforward to shield against that kind of interference, and in fact generally any well made audio equipment is going to be shielded. Anything built properly will surround all the susceptible electronics with either a foil barrier or a metal box and wire the grounds up such that little to no interference makes it through. You and your friends are using a different wireless carrier on a different piece of the spectrum. This is the answer I am leaning towards, actually. I bet you and your friends all switched to T-mobile or Sprint because they are cheaper. ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [April 17, 2017, 5:33pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/3 "2017-04-17T17:33:00Z")
Hmm. My cell phone was 5 years old in 2008 and my first use was in 1993 and I have never heard that sound. Dennis ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [April 17, 2017, 5:34pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/4 "2017-04-17T17:34:37Z")
> [@mixdenny](#): > > Hmm. My cell phone was 5 years old in 2008 and my first use was in 1993 and I have never heard that sound. > > Dennis Interesting. It’s a sound I’m more-than-familiar with. It seemed like all my old flip-phones had it, but I don’t recall hearing it with the smartphones. ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [April 17, 2017, 5:36pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/5 "2017-04-17T17:36:44Z")
Oh, so _that’s_ what that sound is/was! ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [April 17, 2017, 5:39pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/6 "2017-04-17T17:39:48Z")
My understanding was GSM phones caused this interference. If your phone was CDMA from Verizon and Sprint in the US it did have this property. In most richer countries GSM is pretty much phased out. You phone probably still supports GSM but the network it is connecting to is LTE or UMTS. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [April 17, 2017, 5:46pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/7 "2017-04-17T17:46:52Z")
> [@gazpacho](#): > > My understanding was GSM phones caused this interference. If your phone was CDMA from Verizon and Sprint in the US it did have this property. In most richer countries GSM is pretty much phased out. You phone probably still supports GSM but the network it is connecting to is LTE or UMTS. This. TDMA-based GSM (EDGE) causes bursts of AM noise when it is “negotiating” with the cell tower, which is picked up by the radio’s speaker wires and de-modulated by the amplifiers negative feedback circuit. [http://www.geek.com/geek-pick/what-causes-gsm-buzz-1538169/](http://www.geek.com/geek-pick/what-causes-gsm-buzz-1538169/) ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [April 17, 2017, 6:03pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/8 "2017-04-17T18:03:20Z")
I have a Galaxy S7 on AT&T. I get that sound in my electronic ear protection when my phone is trying to connect with a tower. AT&T service is poor at that particular location so it happens regularly. Sent from my SAMSUNG-SM-G930A using Tapatalk ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [April 17, 2017, 7:07pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/9 "2017-04-17T19:07:08Z")
> [@Asuka](#): > > The most obvious answer would be “Speakers are made now with that in mind” but that can’t be all of it can it? My computer still uses a Logitech speaker system from 2002. My latest phone is a Galaxy S6 from 2015, and if I place it near the speaker’s control box (this is the box with volume/tone controls), I hear, through the computer’s speakers, the same sound as in the video you linked to. So I don’t think the phones or their transmissions are particularly different from what they were 10-15 years ago (or at least mine isn’t); it’s just that the present-day ubiquity of cell phones has driven electronics manufacturers to design their hardware with better immunity to such interference. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [April 18, 2017, 2:30am UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/10 "2017-04-18T02:30:50Z")
> [@Machine\_Elf](#): > > So I don’t think the phones or their transmissions are particularly different from what they were 10-15 years ago (or at least mine isn’t); it’s just that the present-day ubiquity of cell phones has driven electronics manufacturers to design their hardware with better immunity to such interference. The phones transmissions are really totally different now from 10 to 15 years ago. 15 years ago 3G was the new coolness. Now 4g or LTE has been out for about 5 to 7 years. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [April 18, 2017, 2:47am UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/11 "2017-04-18T02:47:27Z")
The phone transmissions from 10 to 15 years ago are quite a bit different, but they are still radio waves and can still cause all kinds of interference. These days you are most likely to hear it on computer speakers that have a built in amplifier. Any radio noise that gets coupled onto the audio line from the computer will get amplified. Cheaper speakers will also likely have less shielding and internal electrical noise reduction. TV transmissions have also changed. We’re no longer using analog TV signals. Digital signals are much more immune to noise interference problems. A lot of other stuff is generally designed with cell phone interference in mind these days, which further reduces the chances of you encountering any significant interference in things. It can still happen, though. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [April 18, 2017, 1:30pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/12 "2017-04-18T13:30:38Z")
Here is another youtube recording [GSM, WiFi, UMTS and Bluetooth speaker interferences. - YouTube](https://www.youtube.com/watch?v=iKP5KmPRvHQ) which says “everyone knows this gsm speaker interference”. It is /nothing like/ the gsm 2G thumpa-thumpa-thumpa sound – which I’m not sure was ever heard in the USA ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [April 18, 2017, 2:24pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/13 "2017-04-18T14:24:42Z")
> [@Melbourne](#): > > Here is another youtube recording [https://www.youtube.com/watch?v=iKP5KmPRvHQ](https://www.youtube.com/watch?v=iKP5KmPRvHQ) which says “everyone knows this gsm speaker interference”. It is /nothing like/ the gsm 2G thumpa-thumpa-thumpa sound – which I’m not sure was ever heard in the USA The thumpa-thumpa sound was definitely heard in the US, but I did sign up back in 2003 with a carrier that was GSM (T-Mobile.) I believe it and AT&T were the major GSM players in the US. It turns out the sound in the OP is not the one I was thinking of. (I just assumed it was and didn’t click on it until now.) I was thinking of the thumpa-thumpa that happens before the phone rings or you get a text message. ---
**Author:** ![doubleminus](https://avatars.discourse-cdn.com/v4/letter/d/5daacb/32.png) [@doubleminus](https://boards.straightdope.com/u/doubleminus)\ **Post date:** [April 18, 2017, 2:56pm UTC](https://boards.straightdope.com/t/why-do-we-no-longer-hear-that-dreaded-cell-phone-interference-sound-anymore/784636/14 "2017-04-18T14:56:56Z")
2G phones operating with TDMA media access (one of the first digital methods in cell phones) had a lot of energy radiated with a leftover AM modulation, simply because the access to the channel was sequential. Since then, much better modulation methods were used, in 3G and 4G-LTE. Both the transmitting power was reduce, the peak-to-average power ratio is very low on the transmit channel, so a transmitting phone is much “quieter” in the RF spectrum as before. All these while speeds and quality have drastically increased. And GSM is now used by the great majority of the networks, notably except Verizon and most Chinese providers. Sent from my A0001 using Tapatalk