10khz line

Overview

The 10kHz line is a distinctive audio signature found in recordings from the German radio station NDR during the 1980s. This phenomenon is particularly relevant to the search for "The Most Mysterious Song on the Internet" (TMS), as it helps to confirm the origin of the recording. The presence of this line in the audio spectrum of TMS is one of the technical evidences supporting the theory that the song was indeed broadcasted by NDR.

This line was discovered by TMS Redditor, Fliere and reported in a Reddit post dated Jan 29, 2021: https://www.reddit.com/r/TheMysteriousSong/comments/l80581/the_10khz_line/

Technical Explanation

The 10kHz line refers to a specific attenuation or dip in the frequency spectrum at around 10 kHz. This feature was characteristic of NDR broadcasts and has been confirmed through the analysis of multiple recordings from this station during the era. The line is not a result of broadcasting faults or equipment malfunctions; rather, it seems to be a byproduct of the broadcast equipment or modulation technique used at the time .

Discovery and Importance

The 10kHz line was identified by the TMS research community members who analyzed various recordings from NDR to confirm the station’s audio fingerprint. This discovery provided a significant clue in tracing the origin of TMS, as Darius, the person who originally recorded the song from the radio, and other similar tracks exhibited this same spectral feature. The presence of this line in Darius' recordings but its absence in recordings from other stations like Hilversum 3 helped to narrow down the origin of TMS to NDR .

Speculations and Debates

There has been considerable debate about the cause and significance of the 10kHz line. Some community members speculated about possible technical reasons for its occurrence, suggesting that it could be related to specific models of FM transmitters or modulators used by NDR at the time. Others proposed that the line might be due to the wear and tear on cassette tapes used for recording, though this theory has been less favored .

Further, it was discussed whether this feature could have resulted from a known phenomenon called Sporadic E layer propagation, which might affect radio signal transmission and reception. However, the consistent presence of the 10kHz line in NDR broadcasts across different sources and recordings largely dispels this notion, reaffirming the station-specific nature of this spectral feature .

Conclusion

The 10kHz line remains an essential piece of evidence in the ongoing investigation into the origins of TMS. It not only helps verify the source of the recording but also provides insights into the broadcasting technology of the time. The analysis of this unique audio characteristic exemplifies the detailed and technical nature of the search efforts by the TMS research community. As the investigation continues, understanding such technical details will be crucial in potentially identifying the exact circumstances under which TMS was aired.