I read every word of that same article last night. It does not explain why the same song from different sources is not recognized. Unless buried in their charts and graphs that topic is addressed, I did not see it there. It explains how Shazam recognizes songs, but not why it doesn't recognize every instance of the same song. If it comes down to analog vs digital, then it DOES come down to encoding, as MP3

Riddle me this.

Does live music NOT have the same frequencies as studio recorded music? How does the spectrogram know it is live and not studio? A4 is 440hz no matter what the source is. A3 is 330. A2 is 200, etc.

I need to talk to the Wizard of Shazam!!

I have tested with studio recordings saved as WAV, FLAC, MP3 and M4A. Shazam found all 4 of those. I also grabbed a karaoke version from the web and Shazam found that. That wasn't even done by the actual band! I tested with an MP3 from the CD and the same song ripped from a live concert. Found them. Now I have to dig into a couple of things I hadn't thought of, like how is the audio encoded in the video of that concert. And they do this song at every concert and I have about 6 Cure concerts on m media computer. Off I go! This is truly making me crazy!! Well...