Dan­ger­ous sound? What Amer­i­cans heard in at­tacks

The Mercury News Weekend - - NEWS - By Josh Lederman and Michael Weissenstein The As­so­ci­ated Press

WASH­ING­TON » 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 As­so­ci­ated Press has ob­tained a record­ing of what some U.S. Em­bassy work­ers heard in Ha­vana in a se­ries of un­nerv­ing in­ci­dents later deemed to be de­lib­er­ate at­tacks. 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 lis­ten­ers. 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.

The de­vice pro­duc­ing 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 is also un­clear. The U.S. 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 U. S. Navy, which has ad­vanced ca­pa­bil­i­ties for an­a­lyz­ing acous­tic sig­nals, and to the in­tel­li­gence ser­vices, the AP has learned. But the record­ings have not sig­nif­i­cantly ad­vanced U. S. knowl­edge about what is harm­ing di­plo­mats.

The Navy did not re­spond to re­quests for com­ment. State Depart­ment spokes­woman Heather Nauert wouldn’t com­ment on the tape’s au­then­tic­ity.

Cuba has de­nied in­volve­ment or knowl­edge of the at­tacks. The U. S. hasn’t blamed any­one and says it still doesn’t know what or who is re­spon­si­ble. But the govern­ment has faulted Pres­i­dent Raul Cas­tro’s govern­ment for fail­ing to pro­tect Amer­i­can per­son­nel, and Nauert said Thurs­day that Cuba “may have more in­for­ma­tion than we are aware of right now.”

“We be­lieve that the Cuban govern­ment could stop the at­tacks on our di­plo­mats,” said White House chief of staff John Kelly.

Not all Amer­i­cans in­jured in Cuba heard sounds. Of those who did, it’s not clear they heard pre­cisely the same thing.

The AP has re­viewed sev­eral record­ings from Ha­vana taken un­der dif­fer­ent cir­cum­stances, and all have vari­a­tions of the same high­pitched sound. In­di­vid­u­als who have heard the noise in Ha­vana con­firmthe record­ings are gen­er­ally con­sis­tent with what they heard.

The record­ing be­ing re­leased by the AP has been dig­i­tally en­hanced to in­crease vol­ume and re­duce back­ground noise, but has not been oth­er­wise al­tered.

The sound seemed to man­i­fest in pulses of vary­ing lengths (seven sec­onds, 12 sec­onds, two sec­onds) with some sus­tained pe­ri­ods of sev­eral min­utes. There would be si­lence for a sec­ond, or 13 sec­onds, or four sec­onds, be­fore the sound abruptly restarted.

A closer ex­am­i­na­tion of one record­ing re­veals it’s not just a sin­gle sound. Roughly 20 or more dif­fer­ent fre­quen­cies, or pitches, are em­bed­ded in it, the AP dis­cov­ered us­ing a spec­trum an­a­lyzer, which mea­sures a sig­nal’s fre­quency and am­pli­tude.

To the ear, the mul­ti­ple fre­quen­cies can sound a bit like dis­so­nant keys on a piano be­ing struck all at once. Plot­ted on a graph, the Ha­vana sound forms a se­ries of “peaks” that jump up from a base­line, like spikes or fin­gers on a hand.

“What it is telling us is the sound is lo­cated between about 7,000 kHz and 8,000 kHz. There are about 20 peaks, and they seem to be equally spaced. All th­ese peaks cor­re­spond to a dif­fer­ent fre­quency,” said Kausik Sarkar, an acous­tics ex­pert and en­gi­neer­ing pro­fes­sor at The Ge­orge Wash­ing­ton Univer­sity who re­viewed the record­ing.

Those fre­quen­cies might be only part of the pic­ture. Con­ven­tional record­ing de­vices and tools to mea­sure sound may not pick up very high or low fre­quen­cies, such as those above or be­low what the hu­man ear can hear. In­ves­ti­ga­tors have ex­plored whether in­fra­sound or ul­tra­sound might be at play in the Ha­vana at­tacks.

The record­ings have been played for work­ers at the U.S. Em­bassy to teach them what to lis­ten for, said sev­eral in­di­vid­u­als with knowl­edge of the sit­u­a­tion in Ha­vana. Some em­bassy em­ploy­ees also have been given record­ing de­vices to turn on if they hear the sounds. The in­di­vid­u­als weren’t au­tho­rized to dis­cuss the situa- tion pub­licly and de­manded anonymity.

Cuban of­fi­cials wouldn’t say whether the U. S. has shared the record­ings with Cuba’s govern­ment.

The State Depart­ment has said 22 Amer­i­cans are “med­i­cally con­firmed” to be af­fected and that the num­ber could grow. The symp­toms and cir­cum- stances re­ported var­ied widely, mak­ing some hard to tie con­clu­sively to the at­tacks. The in­ci­dents, which started last year, are con­sid­ered “on­go­ing.” An at­tack was re­ported in late Au­gust.

Cuba has de­fended its “ex­haus­tive and pri­or­ity” re­sponse, em­pha­siz­ing its ea­ger­ness to as­sist the U.S. in­ves­ti­ga­tion.

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