Help! What’s in Apple Music? [SOLVED]

[STC]

The red arrow points to some noise which can be seen in the spectrogram of Apple Music. This noise line can be anywhere and sometimes even above the 20 kHz frequency. It doesn’t appear in every track.

 

[DVDdoug]

It's probably from a CRT video monitor or TV. And it's probably low-level and inaudible. You'll mostly find it on older recordings when they were using CRT monitors before everybody had a computer with a spectrum analyzer... They didn't know it was there.

I would imagine that very-old recordings don't have it because, as far as I know, there didn't used to be computers or TVs in recording studios.

Here's something Google turned-up.

 

[Guermantes]

You can imagine 24 or 48 tracks of that CRT tone being layered during mixdown . . .

Classical recordings were not immune, either. Here's a bit of a Decca recording of Beethoven's Spring sonate with Perlman & Ashkenazy with the 15625 Hz PAL tone:

 

[STC]

Thanks guys. I see them mostly in orchestral type recordings.

 

[Ifrit]

Besides CRTs those could be the interference from LED lighting in the halls, especially on orchestral recordings, that mostly done “live” nowadays. Frequencies vary. But if it is 15625 Hz or around there, it is most likely CRT.

 

[tcli]

16Khz VLF (Very Low Frequency) GBR radio station in Tubular Bell :

 

[STC]

16Khz VLF (Very Low Frequency) GBR radio station in Tubular Bell :

Thank you for this video. Could you tell what plug-in or program is this? Unable to get more info from the page mentioned in the YouTube.

Cheers!
ST

 

[AnalogSteph]

Some sort of SDR software in any case. Here's a more recent article:

Hidden Morse Code in Tubular Bells | MadPsy's Place