Have you ever ever watched an audio speaker’s cone transfer whereas listening to music? If in case you have, you recognize that the cone strikes out and in because the music performs. Have you ever ever puzzled how that motion appears to be like on a microscopic stage? Have you ever ever puzzled how the sound waves themselves really look as they escape the speaker and make their strategy to your ear?
After all you recognize that sound waves are invisible. Nevertheless, laser measurement instruments have develop into so highly effective that it’s attainable to make use of them to measure and visualize sound waves. In reality, Bowers & Wilkins does simply that with laser instruments (1). In a February 2013 weblog submit, the corporate’s senior product supervisor, Mike Gough, described how the corporate makes use of laser measurement instruments to grasp how the assorted elements of a speaker system behave.
In line with Gough, laser measurement instruments are utilized in a number of methods. The primary, and most simple, use includes utilizing a laser to create a 3 dimensional hologram of an object. One other technique referred to as speckle interferometry includes the usage of a video sensor reasonably than a hologram. The sensor is illuminated by laser gentle mirrored by the item and superimposed over the laser gentle. These two strategies are among the many older strategies used, and so they are usually each tough to interpret and susceptible to “noise. Clockwise Tools DICR-0105 Dial Indicator B07C7HH17H”
To beat these issues, Bowers & Wilkins makes use of a method referred to as “Scanning Doppler Velocimeter.” This system measures velocity, not form. Nevertheless, the item’s form could be simulated and superimposed over the picture. Utilizing Scanning Doppler Velocimeter readings, the corporate can consider particular components of a speaker or different object of curiosity. Typically the corporate appears to be like at a single frequency and the outer ring of the diaphragm; different occasions it examines your complete audio band throughout the entire cone.
Along with utilizing a laser device to get exact measurements, Bowers & Wilkins makes use of software program to plot these measurements into two and three dimensional graphs. For instance, Coherent provides a full vary of laser measurement and management merchandise together with laser energy and power meters, laser beam diagnostics, laser instruments, laser mode measuring, and spectral evaluation devices. By utilizing a complete system, it turns into attainable to higher perceive what all these measurements really imply.
What about these invisible sound waves making their means throughout the room to your ears? How do you “see” these? Bowers & Wilkins used laser measurement instruments and a sequence of light-weight cling movie sheets suspended in entrance of a tweeter (2). These movie sheets had been coated with a reflective powder. As an alternative of utilizing the laser device to scan the floor of the tweeter, they used it to scan the sheets as sound performed. Consequently, you possibly can really see the sound waves as they transfer from the scanner and thru the sequence of movie sheets.