D5 on the youtube video "This video will get Donald Trump elected"

Q post 1332 gave us the hint D5 and reposted the youtube link

https://www.youtube.com/watch?v=G2qIXXafxCQ

I need help from some audio specialists

It's a technique called tone insertion, a form of audio steganography.

I downloaded the audio from the youtube video in ogg format, used Audacity to split the stereo into mono and inverted one of the two outputs to remove Trump's speech to listen to the background music like in this example

https://www.youtube.com/watch?v=JYO7Fj5BORM

What I heard was a rhythmic beep throughout the audio. It turns out it was around frequency 587hz or in Scientific pitch notation… D5

To isolate the frequency I went under the classic filter settings, Chebyshev type 2 filter with an order of ten, +0db -10db, highpass cutoff 554, repeat with lowpass cutoff 622hz

The only clear piece I got was near the beginning, before the music cuts in but it's definitely revealing.

Put the first few seconds clip in a morse decoder (the site wouldn't play the entire speech) and played around with the settings

https://morsecode.scphillips.com/labs/decoder/

With an FFT size 512; Filter frequency range 587-587; Volume threshold of 255; Speed (wpm) 70-72 (Trump's age) the introductory beeps are listing out the alphabet

A#DEHDH IJKL MNOP QRST UVWX YZ

T#D EHDH IJKL MNOP QRST UVWX YZ

T#DEHGH IJKH MNOP QRST UVWX #B

Again, anyone with audio skills try this on your own and see for yourself. If you know of a better way to isolate a frequency, know of a better audio format or how to extract the raw audio itself, know of any software that would decode morse, please post it.