Super precise, multiband, notch EQ?

[SamDi]

I'd say it's at 15.6 kHz with an amplitude of -75 dBfs.

So why one would care about a signal, which you can neither from frequency nor from level ever hear? Maybe some dogs or bats might. On vinyl you wouldn‘t even reach a s/n above 60dB, means as soon you have any music signal, the -75dB are far away and masked.

[Benedict]

I'd say it's at 15.6 kHz with an amplitude of -75 dBfs.

So why one would care about a signal, which you can neither from frequency nor from level ever hear? Maybe some dogs or bats might. On vinyl you wouldn‘t even reach a s/n above 60dB, means as soon you have any music signal, the -75dB are far away and masked.

Yeah, I would say that anyone saying they can hear this is chasing self-aggrandizement (their call if it amuses but not 'factual' as such). Even if it were a 200,000,000,000 Watt Turbosound PA, the comparison is still what counts and the main Enya-isms would be so effing loud that their head would have exploded before they could be cognizant of the timid tone.

So while any EQ could cut it, Engineers aren't leaving the tone because they're fools lacking modern Pro-fulness but because they are experienced professionals who know better than to meddle where damage would outweigh any possible gain.

[Synthman2000]

-75dBFS is a non issue but many times it is not -75dBFS. It is greater amplitude than wanted audio signal.