Acoustic Holography – Dr Gary Geaves (Head of Research & Development)

Acoustic Holography – Dr Gary Geaves (Head of Research & Development)

Recently we’ve been looking into the subject of acoustic holography. With this technique, a set of acoustic measurements made in one area of an acoustic field can be used to derive values elsewhere.

For example, by measuring pressure with a rectangular array of microphones in front of a loudspeaker, the pressure on the surface of the loudspeaker can be derived. As you can imagine it is not easy to measure pressure directly on the surface with good accuracy. But once you have pressure on the surface of the loudspeaker, modeling techniques then allow acoustic quantities, such as intensity, to be calculated everywhere external to and on the structure. It’s basically a relatively convenient way of getting a very clear and detailed picture of a radiated acoustic field, which obviously is of interest to us at B&W.

That’s the theory at least and I’m side-stepping some very complex mathematical and experimental problems. We have a project assessing the feasibility of applying this technique to loudspeakers. The good news for us is that the mathematics used is similar to that used for computer simulation techniques that are already very familiar with – we have been using and writing computer simulation programs for 30 years.

3 Comments

  • Antony Watts says:

    Why not do a simple test? Take a SoundField microphone, record something. Then play back through your LSs and see if the original detected sound is the same as the one reproduced by the LSs?

  • Brian Wright says:

    I am an employee at SenSound. We are the world leader in 3D Acostic Holography systems. We would be happy to work with you on this and other applications. This would free you from developing what we have already done. Please visit our site at http://www.sensound.com.

  • Joe says:

    So the surface pressure elsewhere on the speaker cabinet contributes to distortions on the radiated acoustic field direct off the cone? How does FEA contribute to the design of prototypes? Minimalisation of the area of surface stresses?

    JL

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