Instructables

Directional SPeaker

I saw a youtube video of a guy who built his own directional speaker (actually I remember it as a directional megaphone as he would talk into it, and it would target a person). I was wondering how easy it would be to do this? Can we build one with household material? Thanks for being awesome guys!

Kidkodave4 months ago

Hi guys, i've found this great TED talk about a guy who build some:

http://www.ted.com/talks/woody_norris_invents_amazing_things

Autotelic3 years ago
I was just thinking the other day it would be wicked to make one of these things! Apparently.................. http://www.explainthatstuff.com/directional-loudspeakers.html It works a bit like binaural beats, in that an object intercepts the path of two high frequency waves (in this case 200,000hz) and the two waves collide (kinda) and produce a much lower frequency wave that is within the range of human hearing (20-20,000 hz). You need to produce two high frequency waves (with some piezo electric transducers), one is constant and the other one varies according to the input from an audio source (say a microphone). Maybe ou could use an Arduino to process the audio input and convert it into the higher freqs using the tranducers? Then you just stick it inna dish and point it at some unsuspecting passer by!
teamcoltra (author) 5 years ago
Not to "bump" but I am curious also, is there another name for a directional speaker? I cannot find any information on them.
the only names i have heard them be called is directional speakers or spot light audio. from what i understand the speaker produces  ultrasound waves  like those used in medical equipment that travels in the given direction and vibrates molecules in the air producing sound.
mythros mythros4 years ago
Kiteman5 years ago
Maybe you could include a link to the video?
teamcoltra (author)  Kiteman5 years ago
I was looking for it but can't find it (damn the internet being soo big) It was something like college student directional speakers whispers to students in the library. I forget the name :( All I know is that he could point sound at a person
Ah!

I think you need the word parabolic, and it may not be speakers, it might just be reflectors.

A parabolic reflector is the particular shape of satellite dishes and the mirrors in telescopes.

For sound, if you whisper towards the reflector from the focal point, the sound is reflected into a very directional "beam" (not exactly a beam, but you get the idea). If the sound hits another parabolic reflector, then somebody at the focal point can clearly hear the whisper.

In the Science Museum in London, they (used to?) have a giant pair of reflectors, several metres wide, that meant you could hear a whisper right across a large, crowded room.
Kiteman Kiteman5 years ago
Here's a starter for you:

http://en.wikipedia.org/wiki/Parabolic_microphone
http://en.wikipedia.org/wiki/Parabolic_reflector

Museums and similar use parabolic speakers in the ceiling, so that you can stand in front of one display and listen to sound effects or a commentary without disturbing the people looking at thee neighbouring display.
teamcoltra (author)  Kiteman5 years ago
so how do we build one? :)
There's an instructable somewhere about building a parabolic dish for a solar cooker - you could start there.
Goodhart5 years ago
I remember an old Mission Impossible (tv series, not the movies) episode that featured use of a directional speaker and although I wondered how effective it was, I doubted it could be as shown in that episode: peoples seated in a theater, shoulder to shoulder, and one person is singled out to hear something different then the rest.
Mr. Cowboy5 years ago
I saw that exact same vid and I was thinkin of tryin that too but, my dad and I got talkin and it was gonna be tough so we gave up on it but it is possible. Even with household materials.
teamcoltra (author)  Mr. Cowboy5 years ago
Mr. Cowboy maybe we can work together to figure it out and build one? Were you able to figure any of the basics?
eh. I dunno