Patrick Perdue2d ago

#AudioMo day23:

Did you know that there is hidden morse code all throughout Mike Oldfield's 'Tubular Bells' album?

Somehow, probably during the two-track mix-down stage of the album, the CW from a powerful, very low frequency transmitter about 37 miles north of the studio in which this album was recorded found it's way to tape. It's centered at 16 kHz, and so low in the mix that you can't actually hear it... at least, not without some help.

This is a very short, not particularly comprehensive demo using two different methods -- a pair of stock Reaper plugins and an SDR package to mostly isolate this morse transmission, which is heard throughout the entire album.

References:
Hidden Morse Code in Tubular Bells https://madpsy.uk/link-between-the-soundtrack-of-the-exorcist-and-amateur-radio/

The Hidden Signal Inside A Platinum Selling Album - Tubular Bells https://www.youtube.com/watch?v=o3UJAfuvniI

Show threadAndre Louis2d ago
@BorrisInABox If you crank, and I do mean absolutely crank! up the sound on some samples in Air music's Structure and in particular on their Finger Bass track, you can hear what sounds like a French AM station. I haven't done any kind of shifting like you did because I only just learnt about it from this post. All I did was use XferRecords OTT compressor which is free.
Show threadPatrick Perdue2d ago
@FreakyFwoof Oh yes, you showed me some of those samples a long time ago. If it's AM, the same method wouldn't probably do much, because it's a much wider bandwidth.
Show threadAndre Louis
@BorrisInABox I just wonder how many songs have such amazing hidden content in them now?
Also like, VHS recordings run through SDRSharp, could they all be snapshots or at least partial snapshots of shows long gone and things hidden in the spectrum nobody bothers looking for? What a fantastic rabbit hole.
Jun 23 at 7:30pmWeb
Show threadPatrick Perdue2d ago
@FreakyFwoof Back in the 80s, maybe late 70s, someone figured out how to record radio spectrum with a VCR by tapping part of the radio before any tuning or filtering, then reverseing the process so you could essentially tune through that snapshot using a modified radio. Now, you can play those old recordings back with SDR software and do the same. There aren't many of those old recordings online, but there are a few, and it's absolutely a trip.
Someone took that a step further, and transmitted that file using a HackRF, so you can actually use a normal analog radio doing nothing special at all to do the tuning.
Show threadAndre Louis2d ago
@BorrisInABox I definitely want to try that with a regular radio, because yeah. Software is a pain sometimes.
Show threadPatrick Perdue2d ago
@FreakyFwoof You'd have to get a HackRF or something to make that work. BTW, HDSDR is about the most usable thing I've found on Windows so far. Loads of hotkeys. Does the traditional analog stuff. If you want to decode digital, you can just send raw IQ to an audio device, then use specialized software to decode it. Not as nice as SDRSharp with it's many plugins, but also a lot easier to use.
Show threadAndre Louis2d ago
@BorrisInABox I have HDSDR here. Tons of keys, but I never got any sound out of it despite trying for literally hours. It's connected to my roof antenna. I should try again sometime.
Show threadPatrick Perdue2d ago
@FreakyFwoof Oh, I bet you don't have the DLL that connects it to the RTL driver.
Show threadAndre Louis2d ago
@BorrisInABox OO that's a possibility.
Show threadPatrick Perdue2d ago
@FreakyFwoof BTW, RTL's get overloaded very easily on FM if you use an antenna with any kind of gain on them. Having an 8-bit DAC doesn't really do it any favors. It's generally fine for what it's designed for, because usually, you're pulling in signals from small antennas and junk.
I connected my RTL to a Comet CX-333 vertical antenna made for VHF/UHF up on a 33 foot poll, and it got swamped by all kinds of junk, which is why I bought an Airspy R2. IT does a much better job at descrimination, but not everything supports it. I still have to use my RTL dongle if I want to decode HD radio or telemetry from the 433 mHz band, because those applications are made specifically to interface with RTL dongles. But for general purpose capture, the Airspy is way better.
Show threadAndre Louis2d ago
@BorrisInABox I'd buy something different if I knew I'd get it to work, yeah. It seems fine with the TV antenna when using it to decode freeview, but maybe because that's a digital signal.
Show threadPatrick Perdue2d ago
@FreakyFwoof Well, it's designed specifically to do that. Not of any use here. Our TV channels are 6 mHz wide.