Acoustic Camera Displays Noise in 20 Seconds

A simple tool for noise source identification that deploys rapidly to display sound in real-time, and records data for detailed analysis.

Top image: Sound emissions are clearly mapped in seconds with Brüel & Kjær’s acoustic camera.

Acoustic leaks and Buzz, Squeak and Rattle (BSR) are the bane of vehicle developers. Few things will affect the customer’s perception of a vehicle more negatively than annoying noises that seem to shout out to them “something is wrong with the construction quality!” And, since small noises will only develop over time, developers need to hunt and eliminate them rigorously.

PULSE Reflex Acoustic Camera from Brüel & Kjær gives an instant sound map of whatever its user points at. Mounted on the hand-held microphone array is a tablet that displays the sound map, laid over a real-time video of the target. Colour-coded noise contours show the strength of the sound, from which the user can easily determine the sound’s source – from the brightest contours. Good maps allow reliable ranking of noise sources in order of importance.

Beyond the intuitive interface, speed and simplicity are key to the whole product, which has been designed around the goal of getting up and running in 20 seconds for rapid troubleshooting. This target has permeated the development of the hardware and software, and even the box that the battery-powered kit comes in. This approach also ensures minimal training is required to learn to use the acoustic camera.

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Because the acoustic camera displays and analyses noise in real-time, it can map moving objects. And while it streams sound information to the tablet screen, users can walk and move around with it. When the user identifies noisy areas of interest, she can take a screenshot or video using the built-in camera, which helps to easily explain and refer to the measurements later on.

As well as real-time streaming, the acoustic camera can record the data and video, by pressing a button on the microphone array. This is typically done when the user wants more in-depth analysis of the sound than just a rapid noise source identification. Because the camera streams data to a PC at the same time as the tablet, the data is recorded directly to the PC’s hard disk.

After measurements have been recorded, post-recording analysis on the time data uses the software PULSE Reflex™. The acoustic camera is already running inside this software platform, making data transfer and interpretation seamless. 

To analyse the data, the software includes tools that allow the user to adjust aspects of the sound such as the frequency range displayed, helping to narrow the focus of the problem-solving efforts, to pinpoint specific problems.

In use, versatility is key to the acoustic camera’s utility. It is relatively small diameter of 35 cm makes confined spaces accessible, such as small areas of vehicle cabins. For measurements from further away, a removable reflective plate on the array quickly optimizes it. And the ability to incorporate reference signals such as tachometer information enables clear and easy correlation with noise sources, such as the engine’s specific position or gear.

With the acoustic camera from Brüel & Kjær, engineers and technicians alike get a complete noise source identification kit, which has been conceived and optimized for deployment that is as rapid as possible – from a single, global supplier.