I was doing some research about Sound from Ultrasound. In short, this beams two inaudible ultrasound waves at your ear, which interfere with each other after hitting a solid (like you) to create an audible sound wave. In other words, only people standing directly in the beam can hear the sound. This has been marketed as "HyperSonic Sound" (HSS), such as the HSS-450, and the Soundlazer.

There has also been some work with using microwaves and radio waves to create a similar effect, but apparently the energies are too high to be safe for humans.

In 2008, there was some concern this technology would be used for obtrusive advertising.

From what I can tell, this field of research looks pretty dead. The Soundlazer only exists because of a Kickstarter, after all. In 1997, this was expected to become the Next Big Thing. Most of the information I can find about this technology is 10-15 years old, which makes me think there must have been some major drawbacks to this technology. What were they?

Its current use seems to be limited to creating a cone of sound around museum exhibits. What are the drawbacks that keep it from being used for live production audio more frequently? For example, a venue where you have multiple productions at the same time, and don't want the sound to overlap.

  • These devices are also known as "parametric speakers", if anyone is trying to find these on Google. – browly Nov 11 '16 at 19:52
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    I'm voting to close this question as off-topic because speculative "Why" questions don't work well on the stack exchange format, as answers can only be opinion-based. Aside from that, it has nothing to do with sound design, but 'potential' consumer audio products. – Tetsujin Nov 11 '16 at 20:01
  • @Tetsujin I noticed there have suddenly been a lot of views on this question in the past couple days. I have edited it to remove the requests for consumer audio products. It is not opinion-based, as I am asking for historical reasons why attempts to implement parametric speakers have had such limited success, which can be supported by evidence. It is not off-topic, as questions about equipment used to design sound are on-topic. Can the question be re-opened now? Thanks. – browly Mar 1 '19 at 16:51
  • It's not entirely up to me, but it's still a 'why' question, even if it's 'why did it fail' & still doesn't fit sound.stackexchange.com/help/on-topic – Tetsujin Mar 1 '19 at 17:06
  • @Tetsujin OK, I have changed "why" to "what" and clarified the connection to live production audio. Any other issues? – browly Mar 1 '19 at 17:20

Prolonged, close-range use hurts your ears.

From the Soundlazer's FAQs on Kickstarter:

Can I use it on my desk and point it directly at my ears?

The problem is that at close range, you will be hit with 120.5Db of sound pressure that you can't hear! It starts hurting your ears after 10 minutes. Believe me, I know first hand. More realistically, you would point it at the cubical wall or some other object to bounce it so you aren't hit with direct waves. It creates a nice background audio that doesn't travel very far in open areas like offices.

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  • This seems very likely to be the "show-stopping" problem that practically halted further development and exploitation of the phenomenon. – Richard Crowley Nov 11 '16 at 20:05
  • However, Holosonics claims the Audio Spotlight AS-16i is appropriate for personal use, like watching movies. – browly Nov 11 '16 at 20:07

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