note:
- humans don't hear above 20kHz and CD players don't reproduce sound above that, on purpose. If you see a "drop" at 20kHz, there is nothing abnormal about that, at all. hardly anyone bothers to record higher than 20kHz.
- a 15kHz tone indicates FM Stereo broadcast, not TV. (TV pilot is much higher).
Since you say this kHzcame from vinyl directly, the noise here is most likely the noise coming from a CRT's badly shielded flyback during analog transfer. The horiz scan rate for a CRT is 15.734 kHz or so for NTSC.
In short, someone ran their unshielded cable too close to a CRT at some point in the transfer process (or the soundcard was picking it up from the CRT directly, if it was especially noisy). This is very common.
That's all. You can just notch filter it out and never notice. You can;t really hear anything at 15.734 kHz, anyway. If you think you have dog ears nd don't believe me, do a high pass filter from 15kHz-up and tell me what you hear.
It'll sound like quiet bugs fucking in the forest
