In order to achieve beam forming of the sound waves

[lost_in_space]

hello,

i am involved in a private project. for this project it is necessary to control a huge amount of loudspeakers (intensity, frequency) in order to achieve beam forming of the sound waves. However, since i am not an electrical engeneer i really do not have a clue how something like this can be implemented.

does anyone here know how to implemet such an electrical steering system? i would also be very greatful for good literature.


best wishes,

lost_in_space

 

[Bobbywhy]

lost in space, Welcome to Physics Forums!

Here are three sources of literature that may help with your project:

http://en.wikipedia.org/wiki/Beamforming

"ABSTRACT
This paper presents a method of visually steerable sound beam forming. The method is a combination of face detection and tracking by motion image processing and sound beam forming by speaker array. Direction towards a target person can be obtained by the face tracking in real-time. By continuously updating the sound beam direction with the result of the face detection and tracking, the system is possible to keep transmitting sounds towards the target person selectively, even if he or she moves around. Experimental results prove the feasibility and effectiveness of the method."

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1244210

http://www.google.com/#sclient=psy-....,cf.osb&fp=1d93bd05e8ae2937&biw=1343&bih=664

 

[lost_in_space]

thank you for the answer,

the links did help and clearify a bit. however, my big problem is not the steering (there is a huge amount of mathematical methods to do that). The thing i don't know is how to realize a physical implementation. which hardware do i need. how high are the costs for the hardware? are components available and where.

anyway, thank you again,

best wishes,

lost in space

 

[sophiecentaur]

With any system for adding waves (sound or radio) there is a potential problem with the various sources interfering with each other and each element can affect the output of its neighbours. The best way to get round the problem is to have separate amplification for each source and to avoid tuned resonators (ported cavity designs). I am speaking from the standpoint of antenna design, rather than Loudspeaker array design but the principle is universal and the practicalities of doing it with sound are probably easier.

If the array is two dimensional and the beam needs only to be steered horizontally, then it would be possible to feed individual columns but, if you want to control azimuth and elevation, you would need to feed each speaker individually.

To produce the phases for steering the beam, it would be necessary to introduce time delays rather than phase delay as the bandwidth of audio signals is so huge and, in the end, it's equating the time of arrival of the multiple signals that defines the position of the maximum. Is that blindingly obvious? Sorry if it is.
I saw this device, which may do what you need. It depends on the quality you want. It let's you select a 4bit binary combination of time delays up to 255ms.
There may well be other better ones but this was one I bumped into.

 

[lost_in_space]

Thank you for your kind answer. it will take me some time to study the literature.


best wishes lost_in_space