Freesound Forums
Audio Forensic on Phone Tap
Started September 10th, 2014 · 23 replies · Latest reply by damiendada 1 month ago
Hello
I suspect that my phone is tapped using the pizeoelectric buzzer.
More on how this is done is discussed here:
https://www.schneier.com/blog/archives/2010/01/eavesdropping_i.html
There's so much noise on this audio that I can't filter it out. A series of filtering and then amplifying and I can vaguely hear the audio.
The tapped phone audio is here:
https://docs.google.com/uc?export=download&id;=0B5ingIYMt2rmZVRJSUQwZi1wRWc
And the target audio is here:
https://docs.google.com/uc?export=download&id;=0B5ingIYMt2rmVy16emVzdXRNcHc
The first ten seconds of the phone audio, I tried to keep the room silent. At ten seconds I began playing the target audio.
Can anyone help me extract the target audio from the phone tap recording?
Many thanks!
#1 I think you mean a pick-up coil (which is not piezoelectric) ...
https://www.google.com/search?q=pick-up+coil+telephone
#2 The "dirty phone" recording "0B5ingIYMt2rmZVRJSUQwZi1wRWc" is just noise floor ,
similar to pink noise, no voices. "Vaguely audible" is a characteristic of audio-pareidolia ,
where ones brain "hears" voices in what is actually random noise ,
e.g. http://www.freesound.org/people/Timbre/sounds/221637/
Hello Timbre
Are you saying there's no audio in that file?
I'm convinced there is.
My phone is certainly tapped using that method because I've seen the internal modification.
EricaStone wrote:
Are you saying there's no audio in that file?
Absolutely no speech on "dirtyphone.wav" whatsoever.
If you listen to noise generated by electronic devices , now and again there are what sounds like words, but it's Rorschach-audio , ( like the the ink-blots ), random patterns which ones brain misinterprets as having meaning.
It's a normal psychological-phenomenon called pareidolia.
I'm convinced there's audio on that file.
My phone is tapped and that method is well known by the intelligence community.
I'm not an audio expert but can software like Audacity and Audition do the work of High-Gain Audio Amplifier?
The Marty Kaiser amplifier was used to amplify and filter out noise from telephones where the ringer was used as a microphone.
Read the comment by Kevin D. Murray at
https://www.schneier.com/blog/archives/2010/01/eavesdropping_i.html
I quote:
"Hook a high-gain audio amplifier.....You'll believe."
Absolutely no speech on "dirtyphone.wav" whatsoever.
I'll make another recording asap. I could have mixed up the files.
NB: Applying noise-reduction can add artifacts which sound like speech,
see ... http://www.freesound.org/people/Timbre/sounds/248088/ .
If you can't understand what is being said on an original recording, no amount of processing will make it comprehensible, [ the the audio-processing which you see on TV shows like CSI is science-fiction ].
Timbre wrote:
NB: Applying noise-reduction can add artifacts which sound like speech,
see ... http://www.freesound.org/people/Timbre/sounds/248088/ .If you can't understand what is being said on an original recording, no amount of processing will make it comprehensible, [ the the audio-processing which you see on TV shows like CSI is science-fiction ].
Its there. Believe me.
That's the beauty of the technique people find it difficult to find the audio leaking from telephone making it difficult to detect.
I dissaembled my entire phone set, when I connect the ringer/buzzer to a microphone cable and that to a PC, I pick up abosuletly clear audio.
The audio coming from the buzzer is flowing down the telephone line but its screened by all that noise.
I quote from http://yarchive.net/phone/infinity_transmitter.html
"There is actually another methodology which can be applied to
eavesdropping on room conversations using an unmodified telephone set.
Most ringers will function as a variable reluctance microphone, if the
line from the telephone is amplified to an extreme degree, along with
application of suitable signal processing to eliminate an incredible
amount of noise. As in the above methods, the necessary apparatus
must be within a few hundred feet from the telephone set, and the CO
pair must be broken during the operation (with circuitry to detect an
incoming call or outgoing call attempt and reestablish the CO line
continuity to avoid any suspicion on the part of the subject). I am
not claiming that a ringer is a *good* microphone, but under some
selected circumstances this technique can provide useful intelligence.
I may later regret this suggestion, but as an example to
illustrate this principle, here is an experiment that an enterprising
reader can perform using apparatus found in any well-equipped
electronics laboratory. Take a 500-type or 2500-type set with a
bridged ringer and connect its tip and ring directly to the input of a
low-noise amplifier providing say, 80 dB of gain in the voice
frequency range. A suggested approach is to cascade two
Hewlett-Packard 465A amplifiers, with each amplifier being set for 40
dB gain. Take the 80 dB amplifier output and connect it to the input
of a variable bandpass filter having at least 20 db/octave attenuation
(like a Kron-Hite 3100, 3500 or 3700). Take the output from the
bandpass filter and feed it to another amplifier providing 20 to 40 dB
gain and capable of driving a pair of headphones.
Tune the bandpass filter to reject powerline noise, and you have just
turned the telephone set into a crude microphone. At that point it
does not take much imagination to realize that given some competent
engineering resources and a commensurate budget, this technique can be
refined into a practicable eavesdropping device. The availability of
digital signal processing can also do wonders to eliminate the vast
amount of power line, impulse noise and other interference which
develops at the gain necessary for speech pickup sensitivity.
While electromechanical ringers are becoming somewhat a thing
of the past, many electronic telephone sets with tone ringers will
function as an even better microphone. Such tone ringers usually rely
upon a piezoelectric element as the loudspeaker, although a few
low-quality "drugstore-variety" one-piece telephones utilize the
receiver element as the ringer transducer. As most readers of this
forum are no doubt aware, piezoelectric devices will generally
function as both a microphone and loudspeaker. Even a piezoelectric
element optimized for tone ringer use, i.e., with resonance in the
range of 1.5 to 2.5 kHz, will still function as a usable microphone
for lower frequencies.
An on-hook telephone set with electronic tone ringer, if
isolated from the CO line and connected to an ultra-high gain
amplifier with suitable bandpass filtering, and if also subjected to
an appropriate RF bias to cause conduction across the initial
full-wave bridge rectifier and subsequent semiconductor junctions, can
in many instances be turned into a microphone. While this technique
will not work with all electronic telephones, it will work with a
significant number.
The above technique of compromising a telephone with an
electronic tone ringer was first performed almost twenty years ago on
the Ericophone. The Ericophone was an early one-piece telephone, some
models of which contained an electronic tone ringer. While the
geometry of the Ericophone defies verbal description in this forum,
the overall design scheme may best be described as phallic in nature.
Those readers who are familiar with the Ericophone will no doubt
concur with this description 
."
EricaStone wrote:
Its there. Believe me.
I believe the spectrogram which shows "dirty phone" is just [pink] noise with a couple of narrow peaks at 12kHz and 15kHz which are digital sample-rate artifacts. If you don't believe me and the spectrogram, post "dirty phone" on Freesound and ask if anyone can make out any words , ( don't give listeners clues by posting the "target" speech ).
EricaStone wrote:
... connect its tip and ring directly to the input of a low-noise amplifier providing say, 80 dB of gain in the voice frequency range ... The availability of digital signal processing can also do wonders to eliminate the vast amount of power line, impulse noise and other interference which develops at the gain necessary for speech pickup sensitivity.
What you've described is a method of how to create EVP by raising the noise-floor by applying "80 dB of gain" and adding digital processing artifacts just for good measure, which can sound like speech.
Hello Timbre
I think I uploaded the wrong file earlier.
I just created two recordings, here they are
https://docs.google.com/uc?export=download&id;=0B5ingIYMt2rmVDhtdUUyZkZLemc
https://docs.google.com/uc?export=download&id;=0B5ingIYMt2rmcUZnVkt1Wk0zYjA
It has the same background audio as before.
I sincerely hope you find something.
EricaStone wrote:
I just created two recordings, here they are
https://docs.google.com/uc?export=download&id;=0B5ingIYMt2rmVDhtdUUyZkZLemc
https://docs.google.com/uc?export=download&id;=0B5ingIYMt2rmcUZnVkt1Wk0zYjA
"Rec 1" = "Rec 2" = "dirty phone" , all are just pink-ish noise, no speech whatsoever.
I've posted some matching pink-ish noise on Freesound here ... http://www.freesound.org/people/Timbre/sounds/248109/
My noise is computer-generated, not a recording , if you can hear any words on it* that's due to pareidolia.
[ * in the two minutes of Freesound #248109 all I'm getting is an indistinct "severe baking" @ 1:37 - 1:40 ].
Other pink noise on Freesound may be of interest ... http://www.freesound.org/search/?q=pink+noise
A degree of pareidolia is normal , however excessive amounts can be a symptom of mental-illness, particularly when combined with an unfounded belief of being surveilled.
Erica, if you think you are under surveillance, please let people close to you know.
You need to tell people about this so that they can look out for you. Random people over the Internet are not what you need if you feel under threat. Talk to a family member, neighbour, anyone close to you, it really doesn’t matter who, but you need to let someone know if you think your phone is being tapped.
jamesabdulrahman wrote:
Erica, if you think you are under surveillance, please let people close to you know.You need to tell people about this so that they can look out for you. Random people over the Internet are not what you need if you feel under threat. Talk to a family member, neighbour, anyone close to you, it really doesn’t matter who, but you need to let someone know if you think your phone is being tapped.
I totally agree with all my heart.
jamesabdulrahman wrote:
Erica, if you think you are under surveillance, please let people close to you know.You need to tell people about this so that they can look out for you. Random people over the Internet are not what you need if you feel under threat. Talk to a family member, neighbour, anyone close to you, it really doesn’t matter who, but you need to let someone know if you think your phone is being tapped.
This is very true and very good advice.
The question of whether it is possible to tap a phone - The answer is, obviously, yes.
Whether it is possible to do it using the technique you describe? - Maybe.
But you need to ask yourself "would you know if someone was tapping your phone this way?" - The answer to that is "No". All there would be is a connection to your phone line tens of meters away from your house. Out of sight.
What you are describing, is not even a phone tap. - A phone tap is used to listen to someone's phone conversations.
What you describe is turning a phone into a listening device. Basically, a live mic in the room, picking up any sound or conversation in that room.
But again the same question: Even if this can be achieved technically, would you know if it was being done to your phone? - The answer is "no". Any connections would have been made outside your house, not in the phone itself.
Most importantly, you mightwant to ask yourself "Why would someone do it to you?" - There is only point investing the time and the money to bug someone's house this way if they know or do something worth knowing.
I do not think that the answer to this question can be found in this forum.
jamesabdulrahman wrote:
... Random people over the Internet are not what you need if you feel under threat. Talk to a family member, neighbour, anyone close to you, it really doesn’t matter who ...
Generally neighbours are "random people" : just because they live nearby does not make them competent or trustworthy. Similarly, family members are not necessarly competent to assist other family members in any matter. If EricaStone wishes to dicusss their concerns with someone in person it should be a healthcare professional , if it is a mental health problem they may want to keep it quiet because of the stigma attached, and unlike family and neigbours, healthcare professionals are obliged to keep matters confidential.
jamesabdulrahman wrote:
... Talk to a ... neighbour ... it really doesn’t matter who ...
A paranoid person telling neighbours they may have a mental-illness could create a vicious circle :
the neighbours would monitor them more though concern or fear , which consequently would fuel the sufferer's paranoia that they were under surveillance, which they now are, by the neighbours.
Discussing this matter anonymously on the telephone / email / internet-forum are other options.
e.g. http://www.mind.org.uk/information-support/helplines/
I’m inclined to disagree.
As someone with personal experience of mental illness and current experience of family members with the same, coming out and saying to a person exhibiting paranoid or schizophrenic symptoms “You are mentally ill” tends to be a surefire way to convince them that they are completely sane and that their possible ‘delusions’ are totally true. The taboo around mental illness works against such a direct approach.
Of course, the ideal situation is that the potentially unwell person seeks medical help quick sharp and in a hurry. However, ‘straight talking’ is rarely the way to go about this, not in person, and certainly not impersonally over the Internet. Very often the sufferer is convinced that there is nothing wrong with them, and that anyone telling them to visit a doctor is trying to pull the wool over their eyes, is One of Them, is just too ignorant to realise what was going on, etc. When I was convinced that the Fifth Communist International was surveilling my every move and targeting me as the one and only individual who could stop their impending world revolution, this was exactly how I responded.
The hope in advising a potential sufferer of mental illness to speak to people close to them is that they might just be decent enough people to offer some support. All too often, just as they themselves are convinced that they are stone cold sane, people contracting psychosis seem outwardly ‘normal enough’ to everyone around them until it is too late. Hence, it is usually better for those around the sufferer to be clued into the fact that something is not quite right before they reach that stage.
I don’t really have experience of neighbours being ‘random people’ comparable to faceless Internet citizens; perhaps it’s different where I live, who knows.
You can’t get someone to visit a doctor unless they themselves are aware that they are ill. Often that’s 90% of the battle. Now of course, I don’t know whether the person in question here has anyone they know, love and trust around them, but I’d give that the benefit of the doubt. Experience teaches me that my, certain family members’ and certain friends’ lives would have turned out better if only someone was aware that something wasn’t right.
This isn’t meant in any way as a personal criticism, as I know you mean well, just to explain where my advice comes from.
jamesabdulrahman wrote:
I don’t really have experience of neighbours being ‘random people’ comparable to faceless Internet citizens; perhaps it’s different where I live, who knows.
Unless one lives in a community where one gets to vet ones neighbours, then they are essentially "random people".
IMO discussing a possible health problem face-to-face with anyone other than a healthcare professional is risk without benefit : at best they will encourage the person to see a healthcare professional, so might as well cut them out of the loop and speak to a doctor / psychologist , as the involvement of the unqualified person could make matters worse : the last thing a person with persecutory-delusions needs is actual persecution as a result of it becoming public-knowledge they have a mental-health problem.
Discussing such matters (where you can be identified) should be on a need-to-know basis.
I’m afraid I still disagree rather strongly, as the idea that mental illness is something to be kept secret from (absolutely) everyone is one that does far more harm than good. Here in the UK, organisations such as Rethink and campaigns such as Time to Change exist to challenge this misconception.
In addition, it is untrue that in all parts of the world a person can receive professional help for mental health problems when they like. And I’m not talking about remote Pacific islands; I have been waiting 14 months for the ‘routine’ 20-minute psychiatric review that the NHS is supposed to provide for me at least every six months. By and large, the infrastructure to deal with mental illness is not there in this country, ever since Enoch Powell thought that all he had to do was take the dynamite to every Victorian asylum and the problem would go away of its own accord.
Maintaining the taboo is not the way to deal with mental illness, and I find the suggestion unreasonable. As this discussion is now far outside the scope of Freesound or this thread itself, that’s all I’m going to say.
I thank all who have responded to this thread, as I believe you are all genuinely trying to help.
Especially @jamesabdulrahman; Thank you for sharing your own personal experiences.
By now we have probably spooked the initiator of this thread, although that was not our intention.
There is probably no single right answer to any problem involving mental health.
Rarely (more accurately, never) these things go away by themselves. So, in the end, the right solution always is to seek specialist help.
There are many paths to reach that end and what kind of help is available depends on where you live and, saddly, often how much money you have to spend.
Not every path works for everyone. So much depends on the individual's own circumstances and the ilness itself.
What worked for you, or your cousin, may not work for someone else: maybe you had great family support, and they don't, or vice-versa...
At the start of all this there was someone who asked for help. Someone who probably needs help. - This is not a philosophical discussion on the topic.
From here on, I believe we will do more harm than good if we continue onto a violent discussion between ourselves about what exactly is the best path to take.
Enough food for thought and advice has been provided. Lets please stop the discussion here unless there is a further request from the thread originator.