back to article How TV ads silently ping commands to phones: Sneaky SilverPush code reverse-engineered

Earlier this week the Center for Democracy and Technology (CDT) warned that an Indian firm called SilverPush has technology that allows adverts to ping inaudible commands to smartphones and tablets. Now someone has reverse-engineered the code and published it for everyone to check. SilverPush's software kit can be baked into …

  1. Martin-73

    Misuse of computers act, here we come

    *gets popcorn*

    1. Haku
      Terminator

      Re: Misuse of computers act, here we come

      But when the Singularity comes the only laws it will have to obey are those of physics.

    2. Michael Thibault

      Re: Misuse of computers act, here we come

      By the time that case crawls bloodied and bruised down the courthouse steps for the last time, there will be worse digital thuggery in the neighbourhood. The processes of justice have long been considered slow--and they're much too slow now that we've moved, practically everywhere, out of the realm of hours, minutes, and seconds into the realm of milliseconds, nanoseconds, and picoseconds. Reaction times aren't matching up to the pace of change. Catching justice up to a seemingly ever-quickening moving ethical and moral horizon seems a very unlikely possibility. A different kind of change is required.

      1. Pascal Monett Silver badge
        Pirate

        A different kind of change is required

        Yes.

        It is time to set up the Bureau of Sabotage.

        1. Anonymous Coward
          Go

          Re: A different kind of change is required

          Bu of Assassins - much more effective - all get an '00' registration

        2. Anonymous Coward
          Anonymous Coward

          Re: A different kind of change is required

          Think there are a few ministerial departments that fit that bill.

          Its usually the less-than-popular departments in which the incompetent civil servants get promoted sideways to.

          For example the department dealing with FOI requests.

    3. Fatman
      Joke

      Re: Misuse of computers act, here we come

      It will *NEVER* happen!!

      The 'Misuse of Computers Act' only deals with Joe Sixpack's misuse of computers.

      $BIG_CORP'S misuse of Joe Sixpack's computer is perfectly legal. It's a 'free speech' sort of thing, and $BIG_CORP is free to spread his speech any way $BIG_CORP wants. BTW, one of the ways $BIG_CORP """expresses""" his 'right to free speech' is in the form of 'campaign contributions'.

  2. John Smith 19 Gold badge
    Unhappy

    This stuff goes back at least 20 years

    IIRC the concept was a "spread spectrum" signal in the audio to trigger children's toys.

    Obviously when you divided out the spreading code the actual data rate was 1-2Hz

    Seemed highly abusable technology back then.

    Still does.

    1. dan1980

      Re: This stuff goes back at least 20 years

      Jake didn't invent it, did he?

      (Hi Jake : )

      1. sabroni Silver badge

        Re: This stuff goes back at least 20 years

        cue "That's not what we made this thing for!!!"

        1. Dave 126 Silver badge

          Re: This stuff goes back at least 20 years

          > This stuff goes back at least 20 years

          And the rest!

          Halloween III (1982) had the plot of a toy maker distributing novelty Halloween masks with a computer chip containing a fragment of Stonehenge. When the Silver Shamrock TV special airs on Halloween night, the chip will activate, killing the one wearing it and unleashing a lethal swarm of insects and snakes to kill those nearby.

          1. AbelSoul

            Re: Halloween III (1982)

            I used to own a boxed VHS copy of that film and watched it a fair bit as a kid.

            So much so that the very mention of the name has the song bouncing about my head:

            eight more days to Halowe'en, Halowe'en, Halowe'en

            eight more days to Halowe'en, Silver Shamrock

      2. Anonymous Coward
        Anonymous Coward

        Re: This stuff goes back at least 20 years

        [jJ]ake invented everything 20 years ago.

  3. oldtaku
    Big Brother

    Of course Geico

    This is shady as hell. So of course Geico is using it.

  4. Brian Miller

    Surreptitious DMTF?

    Why, of course advertising is driving what was once the sole province of spy agencies! If you want to block it, just wrap your mobile in a cloth to muffle the sound a bit. Or stop watching television.

    Of course, the adware SDK could also listen for distinctive tunes instead of dog whistle sounds. That might take a little more processing power, though.

    1. dan1980

      Re: Surreptitious DMTF?

      @Brian Miller

      "If you want to block it, just wrap your mobile in a cloth to muffle the sound a bit. Or stop watching television."

      Sure, but then what do you do when this technology gets used out on the street or in shopping centres?

      1. Linker3000

        Re: Surreptitious DMTF?

        "Sure, but then what do you do when this technology gets used out on the street or in shopping centres?"

        Then it will be OK, because we will be reassured that, just like MAC address wifi tracking, it's being used to 'enhance our shopping experience'

    2. Doctor Syntax Silver badge

      Re: Surreptitious DMTF?

      "Or stop watching television."

      Just mute the sound when watching live or FF if recorded.

      1. Sir Runcible Spoon

        Re: Surreptitious DMTF?

        Can anyone adequately explain why TV speakers are able to generate sounds outside of human hearing in the first place? What's the point in that?

        1. Stoneshop Silver badge

          Re: Surreptitious DMTF?

          sounds outside of human hearing in the first place?

          It is generally accepted that HiFi reproduction should go up to 20kHz with a maximum roll-off of 3dB. Sure, a lot of people won't be able to hear frequencies that high, but quite a few do, even when over 25. I had a housemate bang my door when I was testing my speakers' frequency response, and had left the generator at about 23kHz afterwards. My own hearing went to 19.45kHz back then. And it's not just straight high frequency sound reproduction that matters, there's also all kinds of step response matters that come into play.

          Anyway, even if an average TV sound system would start to roll-off at, say, 15kHz, it would still be possible to send info to a phone at 17..18kHz, only at higher levels so that it can still be picked up. Only with digital filtering can you effectively create a sharp-ish cutoff at a particular frequency, but that has to be built into the TV's sound processing system. And why should the manufacturer do that?

          1. MacroRodent Silver badge
            Boffin

            Re: Surreptitious DMTF?

            Only with digital filtering can you effectively create a sharp-ish cutoff at a particular frequency, but that has to be built into the TV's sound processing system. And why should the manufacturer do that?

            The audio in digital broadcasts may have been sampled at 32kHz. That was the standard rate in NICAM, and one of the allowed rates in DVB. In fact the lossy compression in DTV might nuke or distort higher frequencies anyway, even if a 44.1Khz or 48Khz sample rate is used: The compressor might decide the near-ultrasound signal is not perceptually significant, and can be thrown away. This could perhaps be defeated by making it loud enough, but then the viewer might notice it.

            1. Adam 1

              Re: Surreptitious DMTF?

              You need to half the sample rate to get the maximum frequency if my memory of Nyquist's theorem is worth the grey matter holding it.

              So a 32KHz sampling rate would correspond to a 16KHz maximum frequency.

              1. Anonymous Coward
                Anonymous Coward

                Re: Surreptitious DMTF?

                "You need to half the sample rate"

                Halve

          2. Paul 195

            Re: Surreptitious DMTF?

            "I had a housemate bang my door" - is that some kind of euphemism?

          3. lambda_beta
            Linux

            Re: Surreptitious DMTF?

            Agreed ... depends on the sound system and amplifiers. Most cheap TVs can't even go up to 12K. Another thing is the microphone in the tablet has to pick up these frequencies.

        2. chivo243 Silver badge
          Pint

          Re: Surreptitious DMTF?

          I for one, cannot, but maybe an analogy works, the missus makes sounds I can't hear...

        3. Alan Brown Silver badge

          Re: Surreptitious DMTF?

          "Can anyone adequately explain why TV speakers are able to generate sounds outside of human hearing in the first place? What's the point in that?"

          Physics - and younger ears can easily hear out to 20kHz

          A more interesting question is how these tones survive in the highly compressed, lossy environment that's a modern TV broadcast chain.

          1. Sgt_Oddball Silver badge

            Re: Surreptitious DMTF?

            Yeah, I think it annoy my littleuns. That and since this is a marketing plot, for want of a better term the people who came up with the idea can go fuck themselves. I like being able to avoid ads and having them force their way into my phone as well... No I won't have it (and not because I'm a prig or some such) especially if the aforementioned littleuns are watching kids shows I don't want my phone to start trying to sell me stuff I don't want to buy I just want to relax.

        4. Anonymous Coward
          Anonymous Coward

          Re: Surreptitious DMTF?

          Flanders & Swann - A Song of Reproduction

      2. Anonymous Coward
        Anonymous Coward

        Re: Surreptitious DMTF?

        or just don't switch on your mobile until you want to use it

  5. Jonski
    Black Helicopters

    But do they sanitise their inputs?

    Should Bobby Tables have the software installed on his smartphone?

    https://xkcd.com/327/

  6. Andrew Jones 2

    Surely iOS devices will require Microphone permission and as of Android 6 (Marshmallow) apps would also require asking users if it's OK to use the Microphone. It'll be pretty obvious if an app you never expect to need to access the Microphone suddenly asks if it can.

    1. MacroRodent Silver badge

      "require Microphone permission"

      That's what I wondered about too, but apps frequently ask for everything, and I guess most users click through without thinking much about it.

      Not sure how this could be fixed. Maybe allow microphone access only to apps that have the text "sound recorder" or "spy" somewhere in their name?

      1. Adam 1

        Re: "require Microphone permission"

        In android 6, you just go settings / apps / [choose app] / permissions and switch off microphone.

        You can turn off all the other bits of everything too. From experience, very few apps have any problem. The worst thing so far is one app thought its licence was invalid until I enabled the particular permission again.

      2. werdsmith Silver badge

        Re: "require Microphone permission"

        Apart from microphone permission, what is the ability of iOS and Android apps to monitor the microphone whilst they are stuck in the background and the phone is in standby?

        I reckon a lot less than is needed to make this kind of process properly useful.

      3. Joe Harrison

        Re: "require Microphone permission"

        OK I shall call my new game "Crispy Cakes!". Hours of fun collect them all!!1! (whilst your stuff is being uploaded to the mothership)

      4. Fihart

        Re: "require Microphone permission"

        Whenever I have been tempted to install apps, I've been stopped in my tracks when simple accessories quite unnecessarily want access to my contacts.

        Bail out at that point.

        Lots of things that apps do can already be done via browser.

    2. Robert Helpmann??
      Childcatcher

      Android 6 Permissions

      Android 6 (Marshmallow) apps would also require asking users if it's OK to use the Microphone.

      Applications written for Android 6 allow you to choose to grant permissions as you install. Those written for previous versions of Android still take the all-or-nothing approach when being installed on an Android 6 device. Once a legacy Android app is installed, users can manually adjust app permissions (they can do this for all apps, in fact). This holds trues for apps that were installed on an older version of Android which was then upgraded.

      I bought a Nexus phone knowing that it would be upgraded to Android 6 soon after. I had previously avoided any app that required permissions that I thought were beyond what they needed. With the new phone, I downloaded everything that caught my eye (almost entirely time wasting games), secure in the knowledge that I would be able to whack any unauthorized access. I got the update and went through every app on my phone to set permissions.

      First, it was a tedious process as the interface is not meant to be used for more than individual changes (Take note, Google!). Second, I denied all rights for pretty much every app I had installed unless the requested rights had a direct and obvious requirement (e.g. access to location is important for getting directions from your current location). I managed to break two games made by the same company; they seem to think that access to my contacts list is needed to play cards. I also found that many, many apps request "Modify, delete and read storage" rights, but don't actually need them to function. This gives an app permission to access to public folders (e.g. photo gallery). I would guess the apps have control over their own files, but they certainly do not need access to my pics and music.

      The ability to control app permissions in Android 6 is a step in the right direction, but it still could do with a bit of polish.

      1. Whitter

        Re: Android 6 Permissions

        What the app says the permission is for is not everything the app can do with that permission.

        e.g. Shopping list with vocal shopping list / reminders (either as sound or as sound-to-text).

        1. Anonymous Coward
          Anonymous Coward

          Re: Android 6 Permissions

          I've found that the number of programs which won't work when you remove permissions is on the increase. XPrivacy is quite good at helping with that as it feeds them fake data.

      2. Doctor Syntax Silver badge

        Re: Android 6 Permissions

        "Those written for previous versions of Android still take the all-or-nothing approach when being installed on an Android 6 device."

        Presumably it would be feasible to direct these requests to /dev/null or a stub function that would just make null returns.

        1. g e

          Re: Android 6 Permissions

          That's always been 'possible' but Google have held off from that for WAY too long as a standard Android feature. They even accidentally (seemingly) had the ability in a KitKat(?) version but a subsequent incremental update nixed it, IIRC

      3. g e

        Re: Android 6 Permissions

        Perhaps some better 3rd party permission managers will appear now marshmallow at least has this much overdue capability

      4. James R Grinter

        Re: Android 6 Permissions

        Alas, Android apps often need access to "external storage" to do the most trivial of things. We developers/publishers of apps would love a finer grained access, and less frightening/misleading descriptions of the permissions displayed to users, but we can't yet always get that.

    3. Alan Brown Silver badge

      "It'll be pretty obvious if an app you never expect to need to access the Microphone suddenly asks if it can."

      The number of apps which want the mike is surprisingly long. Some devs just ask for permissions for everything.

  7. Anonymous Coward
    Anonymous Coward

    I have a smart phone for work purposes

    It gets turned off as I leave for the day.

    I'm not paid for work outside core hours.

    Clock OFF!

    Tinfoil hat ON!

  8. Gumby1
    Pint

    Cricket Anyone

    In Oz a well known Beer brand not dissimilar to that Fosters rubbish we ship overseas would offer a little figurine of Boonie or such past greats when you purchased a carton of said brew.

    These would sit on top of the TV during a cricket match and make funny comment when ever a trigger signal was sent across the TV audio during the match.

    I'll guess they used a similar tech to the SilverPush one.

    Link for more source

    http://theinspirationroom.com/daily/2006/vb-boony-and-beefy/

    1. John Smith 19 Gold badge

      Re: Cricket Anyone

      "These would sit on top of the TV during a cricket match and make funny comment when ever a trigger signal was sent across the TV audio during the match."

      That's the sort of thing I was thinking of.

    2. werdsmith Silver badge

      Re: Cricket Anyone

      The Fosters rubbish that is the choice of the vacuous here is just a branding slapped on generic lager made at a Heineken brewery in Manchester. I think it's probably only the branding that got shipped overseas.

      1. Adam 1

        Re: Cricket Anyone

        > I think it's probably only the branding that got shipped overseas.

        If that's the case, you dodged a bullet.

        1. TRT Silver badge

          Re: Cricket Anyone

          I had a Beavis and Butthead one that was triggered by the IR remote.

          Choice phrases like:

          "Woah! Same crap on every channel."

          "This offends my ears."

          "Hey, Fartknocker. Turn the goddam TV up."

  9. Winkypop Silver badge
    Megaphone

    Tea anyone?

    I think the English need this tech.

    It could be used to start the kettle just before the break in Coronation Street.

    Or even a staged signal by odd and even addresses to help spread out the national electricity peak load.

    https://en.wikipedia.org/wiki/TV_pickup

    1. Dave 126 Silver badge

      Re: Tea anyone?

      Fosters would be unknown in the UK if it wasn't for Barry Humphrey's cartoon strip in Private Eye, and later a film, about Barry McKenzie. Bazza was was a parody of the boorish Australian overseas, particularly those residing in Britain – ignorant, loud, crude, drunk and punchy.

      Not only did Humpries give us Fosters, he gave us 'technicolor yawn' and 'point Percy at the porcelain'.

      1. Captain Badmouth

        Re: Tea anyone?

        Fair Duncan mate, spot on.

    2. Anonymous Coward
      Anonymous Coward

      Re: Tea anyone?

      How about having the "Coronation Street" theme music be used to trigger a TV-B-Gone device?

  10. petur
    Go

    Next up:

    adblockers for TV :)

    1. Pascal Monett Silver badge

      I sometimes mute the sound when ads come on, since they obnoxiously increase the sound level to annoying levels. When the ads are done, I turn the sound back on.

      Looks like I'll be using the mute button a lot more from now on.

      1. RegW

        > I sometimes mute the sound when ads come on, since they obnoxiously increase the sound level to annoying levels.

        Well that's one way for your ad blocker to know where to skip forward to :-)

        1. Captain Badmouth
          Unhappy

          "I sometimes mute the sound when ads come on, since they obnoxiously increase the sound level to annoying levels."

          The peak sound levels are often less than what went before, but commercial sound is compressed so sounds a lot louder.

    2. Adam 1

      Re: Next up:

      Media centre + comskip

    3. hplasm
      Thumb Up

      Re: Next up:

      That, I would like!

      Replace ads with a nice fishtank or perhaps a potter's wheel.

    4. Anonymous Coward
      Facepalm

      Re: Next up:

      You joke, but...

      The latest sets of Smart TVs have banners/smart hubs that advertise the manufactures/partners services.

      So your looking to put on some cartoons for your kids. Then the adverts for Netflix and half a dozen other streaming/download services come up. Let's hope they remembered not to advertise non-kid friendly shows and movies... oh, lots of zombies being decapitated and that big blockbuster of a lady being tied up and kissed.

      Thanks to Smart TVs, I'm sticking to a dumb panel and my own PC/laptop/Media centre to run it.

      (PS, don't have kids but seen the above happen when TVs in use)

      1. Doctor_Wibble
        Joke

        Re: Next up:

        > and that big blockbuster of a lady

        I agree, Rebel Wilson can be very scary at times...

    5. Alan Brown Silver badge

      Re: Next up:

      "adblockers for TV"

      They already exist, even if Rupert doesn't like 'em.

  11. The Vociferous Time Waster

    Pirates

    Embed tones in torrents of movies and put them up on tpb then see which phones ping you to confirm their owners are watching illegal content.

    1. bluesxman

      Re: Pirates

      There's nothing like a little entrapment :-)

    2. petur

      Re: Pirates

      So run a low-pass filter over the audio to kill the ultrasonics.

      Next!

  12. Will Godfrey Silver badge
    Happy

    No Problem

    I haven't had a TV for about 4 years now :)

    ... and my phone is the dumbest one on the market.

    Hmmm. Must give my pitchfork a bit of a polish.

    1. oiseau Silver badge
      Thumb Up

      Re: No Problem

      GMorning:

      > I haven't had a TV for about 4 years now :)

      I'm so glad to know I'm not the only one. =-)

      > ... and my phone is the dumbest one on the market.

      Mine may not be the dumbest one, but it does not have any flavour of that Android virus running it.

      Cheers.

    2. Stoneshop Silver badge

      Re: No Problem

      ... and my phone is the dumbest one on the market.

      So, a Trimfone with a GSM module tacked on?

      1. Will Godfrey Silver badge
        Happy

        Re: No Problem

        Upvoted for shits & giggles.

        Don't give me ideas!

  13. Richard 12 Silver badge

    Those frequencies are too high

    IIRC, the broadcast audio bandwidth is 50Hz to 15kHz.

    So TV broadcast will distort and alias that to buggery - not entirely convinced this can actually work at all.

    1. Dave 126 Silver badge

      Re: Those frequencies are too high

      >IIRC, the broadcast audio bandwidth is 50Hz to 15kHz.

      Eh?

      The audio codecs used in DVB are MPEG-1&2, Dolby AC3 and AAC.

    2. Matthew 17

      Re: Those frequencies are too high

      Dude, the 90's called, they want your analog NICAM TV set back.

      we're all digital now innit, got more audios now.

      1. TRT Silver badge

        Re: Those frequencies are too high

        Dey gimme mo' treble an' bass.

    3. Dave 126 Silver badge

      Re: Those frequencies are too high

      NICAM was digital audio that accompanied analogue video broadcasts.

      NICAM had an upper frequency limit of "15KHz due to anti-aliasing filters at the encoder" ( http://web.archive.org/web/20111017094248/http://stoneship.org.uk/~steve/nicam.html ), which might be where Richard got his figure from.

      1. Anonymous Coward
        Anonymous Coward

        Re: Those frequencies are too high

        The 15kHz came from FM broadcast radio… in particular, stereo FM which used ~DC-15kHz for the base-band mono, plonked a pilot tone at 19kHz then used DSB-SC at 38kHz (2×19kHz) for the differential channel.

        Mono reception was achieved by using a low-pass filter with cut-off at 15kHz.

        Stereo reception was achieved by taking the signal, passing one copy of it through a 15kHz LPF just like a mono set would. A band-pass filter grabbed 30kHz of spectrum around 38kHz and passed that as the input to a mixer. A band-pass filter snatched the 19kHz pilot, fed it to a frequency doubler which then was fed into the LO input on that mixer, giving us the differential signal.

        It was then simple analogue arithmetic (L=Left, R=Right, n=noise):

        (L+R+n) - (L-R+n) = 2L + 2n

        (L+R+n) + (L-R+n) = 2R + 2n

        n is usually fairly small. It'll be higher in the L-R component though because FM has a triangular noise profile.

    4. Tom 7 Silver badge

      Re: Those frequencies are too high

      I'm not 100% certain but most TV's dont have speakers that get near 15khz in reality. Mine claimed to but is 15db down at 10Khz (from the front with a brick wall behind it) and off the scale noticably above that. It lives up to is lower end if you dont mind 30% of it being in harmonics.

      1. Alan Brown Silver badge

        Re: Those frequencies are too high

        "most TV's dont have speakers that get near 15khz in reality"

        Any small speaker will have enough response to output something at these frequencies.

        > It lives up to is lower end if you dont mind 30% of it being in harmonics.

        the THD of speakers is stupidly large anyway. These apps don't care about fidelity. They just need enough of any given tone to work with.

      2. JeffyPoooh
        Pint

        Re: Those frequencies are too high

        @Tom "...khz....db....Khz..."

        kHz (lowercase k uppercase H lowercase z)

        dB (lowercase d uppercase B)

  14. Anonymous Coward
    Anonymous Coward

    What if a repressive regime decided to use it to track the phones of dissidents

    or a democratic governement decided to use it to track the phones of... oh, just any phones, 'cause they can?

    So how long have they? Ten years?

  15. Steve Potter

    HiFi - surely not

    what TV's etc can emit audio at that frequency? got to be a good piece of kit to have that sort of audio amp.

  16. Anonymous South African Coward Silver badge

    Time to break out that Nokia 5230 from long-term storage...

    1. Teiwaz

      Just get something that doesn't get any popular 'apps'

      Firefox, Tizen, Sailfish, Ubuntuphone... (even WindowsPhone, it also doesn't get many apps).

  17. Anonymous Coward
    Anonymous Coward

    Detect, tweet

    Workaround is probably to have an app dedicated to watching for these pings, and shame the broadcaster or store location on twitter in real time.

  18. TRT Silver badge

    Audio frequency response of the human ear.

    I think my hearing must have gone to pot as I've got older. When I was little, I could tell the TV was on by the high pitched whine - could hear it all through the house. Now, I have to look at the little light to see if it's on without a picture.

    Is there a slight sarcasm / joke icon available, btw? Before I get deluged with helpful suggestions.

    1. Kiwi

      Re: Audio frequency response of the human ear.

      You would've been listening to what is commonly called a "flyback transformer" (don't know why, but it is a transformer used to get the rather high voltages used in CRT's). Modern TV's don't have them so that could be why you can't hear it. IIRC it ran at about 16kHz

      Of course, most people take some hearing loss especially of higher frequencies.. I can't even hear 16k now..

      1. Captain Badmouth

        Re: Audio frequency response of the human ear.

        "IIRC it ran at about 16kHz"

        15,625.

  19. Anonymous Coward
    Anonymous Coward

    Flip it around

    Actually, it might be quite good to have a detectable signal embedded in the adverts. Then you can add something to mute the audio output whenever these signals are present.

    Don't try and ban it; make it mandatory!

    :-)

  20. netminder

    COmmercial use of the tech

    I was doing a gig for a major US discount retailer in the US about 10 years ago. They were prototyping this exact technology along with a group of other retailers including a very large electronics outfit. Their take was you would install the app & it would pick up a tone when you entered the store. The app would recognize you & offer you discounts as well as help in finding products. Naturally it also tracked where you went in the store, how long you stayed in any one place and was tied into what you bought. I could see them having offered it as a real nice thing (TM) to help you & get you discounts but the real reason was to gather data on you.

    The testing was not part of what I was doing there so that was about all I learned but given that they have not offered this 'service' I assume they have issues with implementation, but you know if and when they do offer it people will be clamoring to sign up.

  21. This post has been deleted by its author

  22. This Side Up

    Don't use the tv speakers ...

    Feed the sound output to your stereo system via a low pass filter to cut out anything over 16kHz.

  23. Ken Moorhouse Silver badge

    The FM Stereo Pilot Tone...

    ...is 19kHz so FM Radios have to Lo Pass that out for feeding the Audio component through the Amp. So this technology would not work with radio transmissions.

  24. Bob Dole (tm)
    Holmes

    hmm..

    How long until we get AdBlocker phone cases?

  25. JeffyPoooh
    Pint

    I doubt that the speakers in my TV are capable of achieving such lofty freqs

    Home theater, sure. Don't use that every day.

    TV speakers, seems unlikely that'd reach even 15kHz.

  26. Kiwi

    Make the buggers pay...

    So.. Ad company charges client $X per screening. Each time this system picks up an ad being played it will generate a bill..

    So do some research, find out how to make the phone report you're watching the ad, and then sit your phone in a room with a random but very frequent repeat of this. Enough people doing that would mean the advertiser will either move elsewhere, or sue the bad guys for false billing. And/or go out of business.

    Some other ideas.. If you happen to often be somewhere near where a lot of live TV news broadcasts get done from (like near some government or court buildings), wander over and stand nearby (out of shot) with a small audio transmitter built to create these tones.. A few presses of the button and suddenly Apple are being charged for advertising they didn't use. And they don't hesitate to sue people for things that they didn't do (like for "copying" things that were common decades before apple "invented" it)

  27. Medixstiff

    Well if it does affect dogs etc.

    Perhaps the RSPCA can take them to court, animal cruelty cases tend to get excellent coverage these days, put a different spin on the situation.

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