It sounds sort of like a mass of crickets. A high-pitched whine, but from what? It seems to undulate, even writhe. Listen closely: There are multiple, distinct tones that sound to some like they're colliding in a nails-on-the-chalkboard effect. The AP has obtained a recording of what some US Embassy workers heard in Havana in a series of unnerving incidents later deemed to be deliberate attacks that have so far affected at least 22 Americans. The recording, released Thursday by the AP, is the first disseminated publicly of the many taken in Cuba of mysterious sounds that led investigators initially to suspect a sonic weapon. The recordings themselves are not believed to be dangerous to those who listen. Sound experts and physicians say they know of no sound that can cause physical damage when played for short durations at normal levels through standard equipment like a cellphone or computer.
What device produced the original sound remains unknown. Americans affected in Havana reported the sounds hit them at extreme volumes. Whether there's a direct relationship between the sound and the physical damage suffered by the victims is also unclear. The US says that in general the attacks caused hearing, cognitive, visual, balance, sleep, and other problems. The recordings from Havana have been sent for analysis to the US Navy, which has advanced capabilities for analyzing acoustic signals, and to the intelligence services, the AP has learned. Not all Americans injured in Cuba heard sounds. Of those who did, it's not clear they heard precisely the same thing. Yet the AP has reviewed several recordings from Havana taken under different circumstances, and all have variations of the same high-pitched sound. Individuals who have heard the noise in Havana confirm the recordings are generally consistent with what they heard. Click for more analysis of the sound.