Strip one audio stream from a combined stream

Hi all! Apologies for the slightly vague subject line. :slight_smile:

Basically, as part of forensics coursework I have created an audio stream of an image using Coagula.

I then mixed this with audacity to produce a secondary , combined audio stream having changed the rate of the image stream so when they are listened to together the image is not perceptible. ( Hope this is making sense!)

So, I now have the original audio stream which is a song. And the modified stream of the image ‘noise’ and the song.

I’m looking for a way to provide both stream to Audacity and subtract the original stream from modified leaving the image noise.

So, (Modified Stream - Original Song) = Image Noise which I can then run through something like Sonic Visualiser to see the image again.

Is this possible in Audacity at all?

Are you doing all this work in MP3?

Are you using “Image” in the Exact Copy of a Disk Drive sense, or “Selfie At The Beach” sense? Audacity has no image processing abilities.


Hi Koz, thanks for the reply.

Yes I meant image as in ‘Selfie at the beach’ kind, :slight_smile:

I’ve added a png to illustrate.

Coagula did the image to audio conversion so I have a nice hiss and crackle track of noise, the black and white lined image is what Sonic Visualiser spits out after some playing with the spectrograph properties.

I then stuck this track in Audacity along with a generic mp3 (both mp3 btw) and ramped up the bitrate of image.mp3 to conceal it, then rendered both as a new track.

So I need to know, if it’s possible, given both halves of combined track can we split it back down in Audacity?

Cheers for your time. :wink: