[guygee]

Trying to help somebody with this conundrum. The FA and SAs below are supposed to be from a house recording master open reel 7.5 ips (unknown deck). The transfer was done "professionally", so no details are known.
The job is to track, flac, organize and seed. Some of the previous seeds are running here now.

What boggles my mind on this recording is the 16 KHz stripe. This recording does not look like a broadcast FM to me...way too much good frequency content above 16 KHz. So why the 16 KHz spike/stripe?

I am speculating that the 16 KHz tone was injected for pitch control (playback speed control) during taping, and this tape was prepared as a pre-FM, but I would very much appreciate anyone else's informed opinion. Has anyone seen this type of thing before?

Thanks!