Could this be an acoustic signal from an AM radio station?

But... where is the receiver?!

We have been making outdoor acoustical measurements with a sensitive, low noise professional system. One of our measured (microphone) signal contained strange music probably from an AM radio station. This strange, short part in between the acoustic recording was found in data collected during an aurora night. The only thing we are sure about is that this music is NOT Finnish! ;)

The recording is quite noisy - barking dogs can also be heard. The music was audible only 6-7 seconds in a recording of four hours.

DO YOU RECOGNIZE THE MUSIC?

What is this music?

Who are playing, what is the name of the piece?

Which radio station did this come from?

LISTEN and SEND your comments to: repo-raportti@acoustics.hut.fi

IF SOMEONE HAS AN AUDIO TAPE OF THE RADIO PROGRAM IN QUESTION - PLEASE TELL US!!

Date of recording: 27.03.2001 20:41:10 UTC

WAV-sample (10s, 16-bit, 22050 Hz, 442 kbyte)

AIFF-sample (10s, 16-bit, 22050 Hz, 442 kbyte)

Waveform and spectrogram of the music found in the noisy signal. Duration 10 seconds, frequency band: 0-11025 Hz.

The Picture above shows the measuring system used. Typically VLF signal is recorded simultaneously on the second channel.
Unfortunately, this night (27.-28.3.2001) the VLF was not ON.
B&K 4179 has its own high guality, low noise preamplifier with low output impedance.
After some 30 nights outdoor recordings there is no single case where the VLF or any radio interference could be found on the audio tract.
The robustness of the system will be tested in the Laboratory of Radio Engineering at HUT before the final conclusions.

SOME COMMENTS AND ANSWERS SO FAR:

ON THE MUSIC	ON THE MEASUREMENT SYSTEM
M.A. (21.12.01): The instrument is a small (?sopranino?) shawm[1]. The shawm is a double-reed instrument, and is the ancestor of the modern oboe. It is fairly common in the Middle East and parts of India, and the music sounds Middle-Eastern or, just possibly, Indian. It could be from Morocco, Tunisia, Libya, Saudi Arabia, Dubai, Qatar, Oman, Yemen, Syria, Jordan, Turkey, and so on. [1] That's the English name, anyway. It's called a "bombarde" in parts of France, and lots of other names in other countries. They come in all sizes.	M.A. (21.12.01): Could there be (or have been) a temporary bad connection in the microphone cable or somewhere else in the audio chain, such that incoming RF got rectified and the audio component was heard on your downstream equipment? What does your signal chain consist of, from microphone(s), through mixing/preamplification, etc., to the recorder? Is your cabling balanced (differential) 600 ohm throughout, or is part of it High-Z? The problem is much more likely to be in any High-Z part of your signal chain than anywhere else. - - - (see the picture and text above)

SHAWM (listen an example!)

(modified: 8.10.03 - opened: 21.12.01/ukl)