And we placed infrasonic microphones around the elephants as we did these experiments.

进行这些实验时，我们把次声传声器放置围。

And it turns out they're communicating to each other in infrasonic rumbles to warn each other of the threat of bees and to stay away from the area.

后来发现它们次声波段隆隆低语地交流来警告彼此威胁并且远离所区域。

But it travels even further through the earth as infrasonic rumbles.

但随着次声波隆隆声，它地球上传播得更远。

The system, the firm claims, produces frequencies from infrasonic to ultrasonic that are " essentially capable of effectively simulating any ship" .

该公司声称，该系统产生从次声波到超声波频率，“基本上能够有效地模拟任何船只”。