Lrad

[Django Fawkes]

Hi, I want to make an LRAD (or at least whatever comes closest to it) with stuff I can get within a reasonable price.
AFAIK it's just a load of piezo electric transducers put together in a way that makes the sound directional, but to save me from buying it all and ending up with a loudspeaker, can someone tell me what I'm looking for to achieve the loudest sound possible and what I have to do to ensure I can make it directional as I don't know much about the technology or even what a phased array is, but I want to make a sound that can travel as far as an LRAD and all I know is that this seems to be the only thing that can do that.

 

[jpanhalt]

Not quite sure what LRAD is. It would help,if your wrote out that acronym at first use. From the rest of your post, it seems you may be talking about coherent sound. Have you reviewed the Penn State site on coherent sound?

https://www.electro-tech-online.com/custompdfs/2012/06/Demo_Inst5no_specials.pdf

John

 

[canadaelk]

Long Range Acostic Device. Extremely powerfull and directional, a modern bullhorn. It is used by lawenforcement for croud-control. I do not believe the OP has the background for this. Asides from a number of speakers, sophisticated circuitry under computer control are involved. E

On a personal note: Why does everything have to be so loud?

 

[jpanhalt]

On a personal note: Why does everything have to be so loud?

I avoid shopping at Walmart whenever I can. Today was an exception. There was one car in the parking lot that could be heard everywhere, and you know how big Walmart parking lots are. A 22-250 makes less noise (https://en.wikipedia.org/wiki/.22-250_Remington).

Back on point, wouldn't a "laser" directional sound do the same thing. I think the Penn State kit is clever for its simplicity.

John

 

[Django Fawkes]

Not quite sure what LRAD is. It would help,if your wrote out that acronym at first use. From the rest of your post, it seems you may be talking about coherent sound. Have you reviewed the Penn State site on coherent sound?

https://www.electro-tech-online.com/custompdfs/2012/06/Demo_Inst5no_specials.pdf

John

canadaelk got it right. I wanted to make a Long Range Acoustic Device. Basically, all I wanted it for was to make sound that was directional to a range of about 899 meters or somewhere close to that. For me, the fact that the sound can't be heard as well unless you're directly inside the beam is the most important thing.
The Acoustic Laser looks pretty neat and I could definitely use that as a plan b, however I need to be able to use it to produce speech, if it can do that and it's directional, I may well go for that.

 

[Django Fawkes]

Long Range Acostic Device. Extremely powerfull and directional, a modern bullhorn. It is used by lawenforcement for croud-control. I do not believe the OP has the background for this. Asides from a number of speakers, sophisticated circuitry under computer control are involved. E

On a personal note: Why does everything have to be so loud?

I am aware that to use it for speech would require computer control, but I am a computer programmer and have used Arduino in the past. My thoughts were if the piezo transducers were in an array, surely to produce speech from this array, all I would need to do is encode the speech as outputs from the board and deliver it to the array as necessary.
So I wasn't questioning how it would be computer controlled, I was asking purely what speakers/transducers I would need. If you know, can you please tell me what I should be looking for and then I can deal with the rest myself.