Other spectrograms of undetermined sounds.

 

Trivial: What sound can this be ?

Tip: It is an audio registration from an old (Vacuum Tubes) radio, probably tuned on a short wave station.

 
 

This is a strange sound that a friend gave me, you can see below the spectrogram of a few seconds of this sound, and by clicking on the image you can also listen to it.

Screen capture of the spectrography of a strange sound

Looking to the above picture (obtained with another software) you can roughly see the frequency range and the repetition time of the sound.

Monsters spectrogram flipped 90

While working to decipher the sound I noticed that flipping the image 90 would have given something vaguely similar to a monster or a monkey, here is a selection of the above sound, taken with other settings so to enhance the similarity.

If you click on the image you will find a VERY LONG selection (1.63MB MP3) of the sound.

Cleaned up monster

Here is a "cleaned up" version of the above image, the cleaning here refers to the picture and not to the sound, if you use a spectrograph on this sound you will get an image similar to the one above.

If you click on the image you will find a VERY SMALL (20KB MP3) file of one monster repetition only.

Can anyone guess what kind of sound it is ?