Hide and seek in audio files

Hi everybody,

we have to use Audacity and a hex editor to find the hidden message in the file I’ve posted.
I’ve changed the sampling rate from 4410Hz to 44100Hz and now I can hear a voice saying “Keep moving, please! There are no hidden messages at this place!”. Well, I am very sure that there must be another message in this file, but although I’ve tried everything (like checking each offset for correctness), I can’t find it. :frowning:

Can somebody have a look into this, please?

Thank you very much!


Sorry guys, I mixed the file up, but now it’s the original file (I’ll never work again with too many copies…). :blush:

Change the track rate to 96000 Hz and there is a message (in German?)
Did you try looking at the original file in a Hex editor? If there was a text message hidden in Hex data it would have been destroyed when you changed the sample rate.

It’s the same message as it has been with 44100Hz and it says “Keep moving, please! There are no hidden messages at this place!” (BTW: yes, it’s German :smiley: )

I think it has to be a secret audio message, not a message in the hex code. Until last year the trick was to increse the sampling rate and then writing the correct file size in the certain offset, because there was a value much smaller than the correct value and so the player didn’t play the file until the end.
But in this year obviously there is another trick and I unfortunately fail to find it…

So any ideas are still welcome! :wink:

I presume that there is some point to the instruction to use a hex editor, in which case we’ll need a direct (bit perfect) copy of the original file.

I’ve downloaded the file from my first post and obviously I’ve uploaded the wrong file, since it was a copy I worked with. :blush:
I’ve edited my first post and now it’s the original file they gave us for working with.

Sorry again. :blush:

It looks like the same file to me.

The thing is, that I’ve downloaded the previous file from my first post and it was named as “110-220-440-880.wav” - it also made a different sound. Anyway, now it’s definitely the correct file… :slight_smile:

I’ll keep trying to “play” with the hex editor and I’ll inform you immediately in case I find a solution.
But since my audio knowledge is very limited, any ideas from you experts are still very welcome! :wink:


The file attached to your first post is named secret_message.wav
it is 978.0 KB (1001516 bytes)
it has a sample rate of 4410 Hz, 16 bits 1 channel PCM WAV.

Then everything is just perfectly fine. :wink:

BTW: this exercise is very stupid. I mean it’s just a stupid “find-the-error-game”…

Perhaps that is the answer and you’re looking too hard for more?
Changing the sample rate to about 88200 Hz sounds about right.

Steve, I did an important step, but it seems like magic to me:

1.) The sampling rate must be 44100Hz. Changed with hex editor.
2.) The ‘number of channels’ value in hex editor was 1 and I changed it to 2.
3.) Playing the changed file with Audacity you can hear on the right speaker the male voice with the text I posted above. But on the left speaker you can hear a female voice wishing a Merry Christmas. :smiley:

Well, in Audacity now there are two audio tracks, but only the second one shows waves, while the first one doesn’t show any waves. Do you have a dummy friendly explanation for this?

Thank you very much!

It does show waves but they’re very small, you need to amplify the secret female voice track to make the waveform more obvious …
Split the stereo to mono, select the upper (was “left”) track, and apply “Amplify” on default (amplifies by 40dB :open_mouth: ) …
secret message, split to mono and amplify the 'flat line'.png

Thank you very much, Trebor! Now everything is clear. :wink: