Being able to direct sound is useful in many situations. Two examples are at a museum where people standing in front of two different exhibits can hear two different commentaries or at home if you don’t want to hear the crap someone else listens to.
This is where modulated ultrasound comes to the rescue – the ability to direct sound with an impressive 5 – 10° spread – that’s unheard of with any traditional loudspeaker.
Lets take a quick look at how this craziness works because it’s not your typical transducer, that’s for sure.