Have you anytime every time situated an audio speaker’s cone go when listening to audio? For just about any person who may perhaps nicely perhaps have, digital distance meter you entirely grasp the cone moves in and out as obtaining the manufacturer new tracks performs. Have you ever anytime at any time at any time each time questioned how that motion would seem all around the microscopic diploma? Have you ever at any time anytime at any time anytime every time questioned how the audio waves on their own possess rather have unquestionably current up furnished which they escape the speaker and make their strategy in course throughout the ear?
Plainly you accept that audio waves are invisible. Nonetheless, laser measurement layouts have gotten so productive that it really is certainly probable and that is all set to aid rely upon them to guage and visualize manage to develop into waves. In special really serious fact within the situation, Bowers & Wilkins does just that with laser resources (1). In a February 2013 blog post, the company’s senior product manager, Mike Gough, described how the company uses laser measurement instruments to have an understanding of how the various components of a speaker system behave.
According to Gough, laser measurement products are used in several ways. The first, and most basic, use involves using a laser to create a three dimensional hologram of an object. Another approach known as speckle interferometry involves the usage of a video sensor fairly than a hologram. The sensor is illuminated by laser light reflected by the object and superimposed over the laser light. These two methods are among the older methods used, and they tend to be both difficult to interpret and prone to “noise.”
To overcome these problems, Bowers & Wilkins uses a process known as “Scanning Doppler Velocimeter.” This technique measures velocity, not shape. However, the object’s shape can be simulated and superimposed over the image. Using Scanning Doppler Velocimeter readings, the company can examine distinct parts of a speaker or other object of interest. Sometimes the company seems at a single frequency and the outer ring from the diaphragm; other times it examines the entire audio band across the whole cone.
In addition to using a laser device to get precise measurements, Bowers & Wilkins uses software to plot those people people measurements into two and three dimensional graphs. For example, Coherent offers a full range of laser measurement and control products including laser power and energy meters, laser beam diagnostics, laser resources, laser mode measuring, and spectral analysis equipment. By using an entire technique, it becomes doable to better know what all these measurements certainly mean.
What about all people people invisible appear to be to be being waves making their way across the room while in the way of your ears? How do you “see” those people people? Bowers & Wilkins used laser measurement tools and a series of lightweight cling film sheets suspended in front of a tweeter (2). These film sheets were coated with a reflective powder. Instead of using the laser software to scan the surface from the tweeter, they used it to scan the sheets as present up to be played. As a result, you can in simple fact see the audio waves simply because they move from the scanner and through the series of film sheets.
If you’ve anytime puzzled how precise laser measurement instruments are, the actuality that they can be used to measure invisible sound waves makes them solid indeed!