Q: How Much Can Your Phone Hear? A:Testing Shows One Microphone Picks Up Sounds From Every Room

You may have read about how microphones in your various devices Such as your phone can record and send audio without you knowing about it. Besides your phone, these devices could be your:

TV

Computer

Various consumer devices marketed by Amazon.

Tablet

And possibly your:

Video and still cameras

A few interactive children’s toys that are programed to have a conversation and ask questions.

Your car.

Any device that has the capability of being connected to a phone line or the internet.

I have a friend who has an ap on her phone that has a name and you can say its name and then ask a question. Sometimes there will be a noise in the room and her phone will say something like “I did not understand that”. This thing is always running in the background. A few years ago I did an instructable article showing how to make a power supply to power condenser microphones.

Link

:https://www.instructables.com/id/Condenser-Microphone-Power-Supply/ Multiple pages.

 

I recently purchased some new microphone elements and picked a winner. It is an improvement over what I was using before and cost only $5. This makes it officially a cheap microphone. I power it off my cheap single transistor preamplifier I built and I use a cheap USB interface that I bought on Ebay (typically around $10 – $15) to make MP3 files.

I have been making all kinds of test recordings with dirt cheap audio devices. Below are a few test files with a single microphone in the dining room. My conclusion is that a mic placed in a more central location might be sufficient to record sounds all over the house if all the interior doors are open. Note that no attempt was made to minimize ambient noise. It is realistic testing of a likely scenario. You come home from work and toss you keys and phone on the table and start yapping about your day. Everything you say can be recorded whereever you are.

The first file is me talking as I walk around the house.

https://cdn.instructables.com/ORIG/FBY/8RRX/JAIJLJZ2/FBY8RRXJAIJLJZ2.mp3

The next recording is a clip from the middle of the first recording with the volume boosted 20 db.

https://cdn.instructables.com/ORIG/F4Q/VMUB/JAIJLCME/F4QVMUBJAIJLCME.mp3

The next recording is like the second recording but with the graphic equalizer included with the USB interface to adjust the bass and treble for greater clarity.

https://cdn.instructables.com/ORIG/FZH/FFEW/JAIJLE46/FZHFFEWJAIJLE46.mp3

I’m not an engineer. Can you imagine what real enineers are doing with intent to do it and state of the art parts and equipment,

Here is a recording with the microphone more centrally located in the house (no edits):

https://www.instructables.com/files/orig/FOV/SRJF/JAMTPY1B/FOVSRJFJAMTPY1B.mp3

2nd try with the centrally located mic. This recording was boosted 10 db after the recording.

https://www.instructables.com/files/orig/FEU/XF8M/JAMTW470/FEUXF8MJAMTW470.mp3

And here is the same recording with edits leaving only the part with me in the bedroom and bathroom. I added 20 db after the recording in addtion to the original 10 db.

https://www.instructables.com/files/orig/F7I/P6WD/JAMTW477/F7IP6WDJAMTW477.mp3

This last recording is quite telling. Yes, just one of your devices can pick up just about everything in every room 24/7.