Simcenter Sound Camera – Everything you need to know
Knowing where a noise originates is the first step in addressing it!
The Simcenter Sound Camera is a sound source localization tool that makes it quick and easy to pinpoint noise sources – just point the Sound Camera at an object, and the purpose-built Sound Camera software instantly shows results in an easy to interpret picture (see Figure 1).
The Simcenter Sound Camera is a multi-channel microphone array, built on digital MEMS technology. All the signal processing is built into the Sound Camera, so there is no other equipment required: no external microphones to plug in or calibrate, no big acquisition module to lug around. Simply plug the Sound Camera into the laptop via a standard Ethernet cable, and start solving the noise problem.
This Simcenter Sound Camera article covers:
Sound Camera Features
All the necessary signal processing is performed on-board the Sound Camera, no external “DAQ” front-end is needed. A single Ethernet cable connected to the PC is all that is required.
Integrated into the rugged aluminum frame of the Sound Camera are 45 digital MEMS 24-bit microphones. (See Figure 3 below) MEMS microphones are etched directly onto a silicon wafer, making them very small, stable and durable. They feature a high signal-to-noise ratio, very low power consumption, and good sensitivity. MEMS microphones are often used in smart phones due to their reliability, stability and robustness.
The Simcenter Sound Camera also comes with a wide-angle video camera and an infrared distance sensor (see Figure 3). The wide-angle lens provides an extended field of view. This feature allows the Sound Camera to be moved into the acoustic near field, close to the noise emitting object, and still provide a view of the entire object. Source localization is performed live in real-time with the video feed, making the Sound Camera perfect for localizing noise on moving objects, or for hand-held trouble shooting. The built-in distance finder continually updates the distance to the measured object for optimal localization results.
One of the Sound Camera’s most revolutionary features is its ability to be configured in three different sizes: Center section, Center + Short Arms, Center + Long Arms (see Figure 4). By adding one of the two optional arm extension kits, the diameter of the Sound Camera can grow, greatly increasing the spatial resolution and frequency range of the antenna. As the frequency of sound gets lower, the wavelength (size) of the sound waves grow longer. By increasing the overall diameter of the array, the arm extension kits make the Sound Camera capable of localizing lower frequencies.
The circular center section of the Sound Camera features 45 microphones, and has a diameter of 28 cm. By adding one of the optional arm extension kits, additional microphones can be added, increasing the spatial resolution and expanding the applicable frequency range. The short arm extensions add 4 microphones to each of the nine arms, totaling 81 microphones, with an overall diameter of 60 centimeters. The long extensions contain 8 microphones each, bringing the total number of microphones to 117, and an array diameter of 150 cm.
Standard Sound Camera hardware also includes an input for up to four additional transducer signals to be measured simultaneously with the microphones built into the Sound Camera. By pairing the Sound Camera with Simcenter Testlab HD Acoustic Camera software, these signals can be used to provide coherent phase references for additional processing.
Simcenter Sound Camera also comes equipment-ready to be combined with other Simcenter SCADAS data acquisition systems (see Figure 5). By combining the SCADAS and Sound Camera, the Sound Camera’s sound source localization capability can be combined with standard data acquisition campaigns including measurements with tachometers, CANbus channels, GPS data, and more. All data is time-aligned and recorded simultaneously in Simcenter Testlab software.
Included & Optional Equipment
The Sound Camera comes packaged as a complete kit, with everything you need in one rugged, weatherproof carrying case (Figure 6).
Sound Camera Software Overview
The Sound Camera software is designed to produce sound source localization results quickly and easily. The main screen area of the software is broken up into four main sections, as shown in Figure 7 below. These sections are:
The user selects a band of interest in the live frequency spectrum using the double cursors, and the hologram display updates automatically (Figure 8), highlighting the noise source for the selected frequency band. The level contribution display in the upper right gives an indication of how much the selected frequencies contribute to the overall noise level. The reference snapshot display can be used for quick A/B comparisons: for instance, when testing different product variants, or evaluating sound treatment packages.
Making a recording of the data is also possible and allows for further investigation and replay. The user has the option to continuously loop the playback over a specific range of time (useful for transient events) or can choose to average the sound data over the entire selected range for stationary noises.
Sharing and communicating Sound Camera results is easy – localization results can be saved and exported as a still picture, or a movie file.