I've heard of directional speakers being used in trade show exhibits. What are they, and how do they work?

Trade shows are cacophonies of sound, with presenters blasting attendees here and multimedia engagements battering them there. But if you'd rather not overwhelm your booth visitors with sound, a directional speaker can point and limit audio waves to a specific area in much the way a spotlight directs a beam of light to a precise location.

In comparison, a conventional speaker broadcasts sound over a broad area. So it basically sends out sound waves that, just like a droplet in a body of water, spread outward in all directions. As the waves spread, their energy – and therefore their volume – diminishes. On the other hand, directional speakers use ultrasound waves, which are different from those emitted by conventional speakers. While there's a lot of technical intricacies involved, suffice it to say that these types of waves stick together as opposed to spreading out, generating a column of sound that pretty much stays put and remains strong rather than rippling out and dissipating.

For exhibitors, then, directional speakers allow you to contain sound within a specific area, e.g., directly in front of a product display. Doing so is a bit of a public service, as it cuts down on the aforementioned trade show cacophony that can alienate booth visitors and irritate neighboring exhibitors trying to hold one-on-one discussions. But perhaps more importantly, it helps you to purposefully control the sound within your exhibit, creating full-volume experiences in some spots and quiet, contemplative zones in other areas.