Acoustic holography is an excellent technique to visualize structure borne sound. It requires the microphone array to be positioned in the near field of the sound source. With a near field microphone array like the Fibonacci the holography methods SONAH and HELS can be used to generate acoustic maps of the sound pressure, sound intensity or particle velocity. Due to its microphone layout and the integrated Intel® RealSenseTM Depth Camera the Fibonacci not only excels at standard beamforming but also at near field acoustic holography as well as far field measurements.
The Fibonacci array represents a new array family allowing near field and far field measurements with the same hardware. The integrated Intel® RealSenseTM Depth Camera provide optimal reference images. For the measurement of pass-by applications and holography, the Baumer camera is recommended. The application area of this array ranges from 30 Hz for holography measurements to 20 kHz for beamforming measurements. This array can be operated with the mcdRec data recorder.
| Array body diameter | 79 x 79 x 17 cm |
| Weight | 9 kg |
| Video camera | Intel® RealSenseTM Depth Camera D435 |
| Resolution | 1920 x 1080 (Full HD) |
| Microphones | Electret condenser capsule + special designed preamplifier |
| Frequency response | 20 kHz – 60 kHz (< 15 dB) 100 Hz – 15 kHz (< 0.5 dB) 20 Hz – 20 kHz (< 3 dB) |
| Max. sound pressure level | 130 dB at 3 % THD |
| Noise level | 27 dB(A) |
| Sensitivity | 20 mV/Pa |
| Channels | 72/96/120 |
| Recommended measurement distance | SONAH: 10 – 20 cm HELS: 0 – 10 cm BF: > 0.8 m |
| Acoustic mapping range | 72 channels: 9 dB – 130 dB 96 channels: 8 dB – 130 dB 120 channels: 7 dB – 130 dB |
| Recommended mapping frequencies | SONAH: 40 Hz – 2 kHz |
| Dynamic range (Distance to the source: 1 m; calculation points: 90.000) | 72 channels: 14 dB – 20 dB up to 50 dB with advanced algorithms |
| Ingress protection code | IP20 |
| Cable length to data recorder | up to 20 m (on request: 50 m) |
| Operating environment | 0 °C – 35 °C, up to 80 % RH (RealSense) 0 °C – 45 °C, up to 80 % RH (Baumer) |
For near field and far field applications
This array can be used for beamforming as well as for holography (HELS and SONAH) applications. Depending on the chosen method, the recommended measurement distance is between 0 and 10 meters. The area of application is between 30 Hz for holography measurements up to 25 kHz for beamforming measurements. owing to the arrangement of microphones, near field and far field measurements can be conducted with only one array.
The array design is optimized to provide the highest spatial resolution as well as map dynamic possible given the number of microphones used. Additionally, the array design effectively minimizes partial reflections, sound pressure doubling effects on the surface, and resonance effects between the measured object and the array.
The microphones used are calibrated to ensure stable sound pressure levels (+/- 0.5 dB). The array is connected to the data recorder via differential SymBus microphone connector cables. This technology allows for long microphone cables (max. 20 m). The array comes with two Baumer Ethernet cameras. The included high-end Manfrotto tripod allows a set up in almost any measurement environment imaginable. Array and tripod are supplied in a transport case and bag, respectively.
By activating external content from Youtube, you consent to transmitting data to this third party.
