Simcenter Testing Solutions Simcenter Sound Camera - Everything You Need to Know

Direct YouTube link: https://youtu.be/An-oO3bTjok

 

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).

 

Figure 1. Sound Camera results are overlaid on a picture or video, making them easy to understand.

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:

1. Sound Camera Features
2. Included & Optional Equipment
3. Sound Camera Usage Overview
4. Reference Material

Sound Camera Features

• Integrated electronics

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. See Figure 2.

Figure 2. Sound Camera features integrated signal conditioning, sending digital data directly to the host computer without the need for a separate front end.

• Digital MEMS microphones

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.

 

Figure 3. Sound Camera features digital mics, video camera and automatic range finder built in!

• On board wide angle video camera and distance sensor

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.

• Modular arms for flexible frequency ranges

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.

Figure 4. The Sound Camera can be configured in 3 different sizes by adding optional arm extensions.

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.

• Input for additional transducers

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.

• Multi-frame operation capable

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.

Figure 5. Simcenter SCADAS and Sound Camera can be combined to add sound source localization capability to any high-channel count measurement.

Included & Optional Equipment

The Sound Camera comes packaged as a complete kit, with everything you need in one rugged, weatherproof carrying case (Figure 6).

Figure 6. Included equipment for the Sound Camera. Optional short arm extensions shown.

1. Circular center section (45 microphones) with integrated electronics, wide-angle video camera & infrared distance sensor. Includes wind screen.
2. PoE (Power-over-Ethernet) adapter w/ power cord
3. 5m network cable to connect array to PoE adapter
4. 1m network cable to connect PoE adapter to PC
5. AUX-IN breakout cable with 4 female BNC connectors
6. Multi-pin connector for optional external battery & IRIG-B (multi-frame operation)
7. Manfrotto tripod
8. Pistol-grip handle for hand-held operation
9. Rugged Pelican case with customized foam
10. Sound Camera software (not pictured)

Options

• Arm extensions
  • Optional short arm extension kit (total 81 microphones)
  • Optional long arm extension kit (total 117 microphones)
• Simcenter Testlab HD Acoustic Camera software – enables advanced post-processing functionalities that can be applied to recordings made with Sound Camera. Additional capabilities include
  • Coherent processing using external sensors.
  • Enable multi-frame mode with Simcenter SCADAS hardware for high channel count tests.
  • iNAH – nearfield acoustic holography algorithm. Improves low-frequency localization results and allows sound power quantification/ranking of sources.
  • Order Extension – localization vs RPM, .
  • Deconvolution – Allows increasing the spatial resolution of farfield beamforming measurements.

 

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:

• live frequency spectrum with selection cursors
• live overall level and band contribution level
• live hologram localization results
• reference snapshot, making for easy A/B comparisons on the fly

Figure 7. Sound Camera software is designed to be easy to use, providing real-time results with no need for extra processing.

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.

Figure 8. Selecting different frequency bands show distinct sources of noise. Notice the engine cover seems to be doing its job – the noise only appears to come from the edges!

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.

Questions?  Email Scott MacDonald (macdonald@siemens.com).

Reference Material (download links to zip file)

• Simcenter Sound Camera Brochure
• Simcenter Sound Camera User Manual

Related Links

• Index of Testing Knowledge Articles
• Simcenter Testlab: HD Acoustic Camera
• Simcenter Testlab Array Data Reporting
• Simcenter Testlab: Sound Power Calculation with HD Acoustic Camera
• Simcenter Testlab: Improving Low Frequency Results with Acoustic Array
• History of Acoustics
• Sound Pressure
• What is a decibel?
• What is A-weighting?
• Octaves and Human Hearing
• What is Sound Power?
• Decibel Math
• What is the Acoustic Quantity called Q?
• Sound Absorption
• Sound Transmission Loss
• Noise level certification, how to select the right standard?
• Sound pressure, sound power, and sound intensity: What is the difference?
• Sound fields: Free and diffuse field, near and far field
• Loudness and Sones
• Auditory Masking
• Tone-to-Noise Ratio and Prominence Ratio
• Fluctuation Strength and Roughness
• Critical Bands in Human Hearing
• Kurtosis
• Sound Quality Jury Testing
• Simcenter Sound Camera YouTube Playlist