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NTEK Omni-directional Sound Source (4" HP)
- 1. OMNI 4” HP Omnidirectional sound source www.ntek.it
- 2. This paper shows the results of the measurements done to assess the compliance of the sound sources with the requirements stated in ISO Standards 3744 and 3382 about sound power and directivity of sound sources. The entire measurement was conducted following the guidelines provided by the International Standard Organisation about this kind of tests, in particular the procedure is compliant with ISO Standard 17025. Table of contents Tested Source ........................................................................................ 3 Measuring environment ...................................................................... 4 Measuring equipment .......................................................................... 6 Results ................................................................................................... 7 Sound power ................................................................................. 7 Sound pressure ............................................................................. 8 Directivity ...................................................................................... 9
- 3. All information subject to change without notice Tested Source Model OMNI 4” HP Omnidirectional sound source Diameter (mm) 280 Weight (Kg) 7.5 Impedence (ohm) 3 + 3 Number of speakers 12 3 The sound source was fed with Pink Noise using an AMG Mini Digital Amplifier. During the measurement the sound source was installed on a rotating device (MB01) free to move on its central axis for 360° (see Fig. 1). Fig. 1 Photos of measured source and measurement conditions
- 4. All information subject to change without notice Measuring environment In Figure 2 is reported a simple drawing of the anechoic chamber used for this measurement. The height of the chamber is 2.63 m. 3530 3170 360 3450 1500 3780 Mic 2 Mic 1 Sound Source 5 0 0 Fig. 2 Mic placement – Mic 1 is for sound power measurement, while Mic 2 is for sound pressure one. Distances in mm Type Temperature Humidity Pressure Hemi-Anechoic Chamber 23 ± 1 ° C 30 ± 15 % 994 ± 10 hPa 4
- 5. All information subject to change without notice K1 and K2 correction factor are negligible because of the environment of the measurement (hemi-anechoic chamber). The chosen procedure was the one of a high machine with a narrow base due to the assembly of the sound source (see Source Tested for a reference). The next tables show the values of L1, L2, L3 and D for this speaker and, hence, the values of A, B, C and S. L1 (m) L2 (m) L3 (m) D (m) 0.28 0.28 1.67 0.5 A (m) B (m) C (m) S (m2) 0.64 0.64 2.17 12.75 Fig. 3 Representation of measurement procedure as indicated in ISO 3744 5
- 6. All information subject to change without notice Measuring equipment Device Model Manufacturer Serial number Sound level meter Microphone Preamplifier Sound Calibrator Rotating device NL-52 UC59 NH-25 NC-75 MB-01 Rion Rion Rion Rion Ntek 00342833 12852 10461 34891821 Ntek Calibration Lab test tool The microphone used for the measurement was equipped with a windscreen. 6 To measure the sound source the Rotating device was used in order to “sample” the source every 5° as stated within the ISO Standard. The microphone was left in the same position for the entire duration of the measurement. The data aquired was, then, processed with the help of a dedicated software that, with a proper algorithm, led to the results indicated in Results section.
- 7. All information subject to change without notice Results In this section are reported the results of the measurements about the sound power of the source and its directivity. Lw = 128.0 dBA Fig. 4 Sound Power Level Spectrum - 1/3 oct Sound power 0,0 20,0 40,0 60,0 80,0 100,0 120,0 140,0 16 20 25 32 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000 dBA Frequency (Hz) 7
- 8. All information subject to change without notice Lp: 117 dBA Fig. 6 A Weighted Sound Pressure Level – 1/3 octave -20,0 0,0 20,0 40,0 60,0 80,0 100,0 120,0 16 20 25 32 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000 dBA Frequency (Hz) Lp linear: 119 dB Fig. 5 Linear Sound Pressure Level – 1/3 octave Sound pressure 0,0 20,0 40,0 60,0 80,0 100,0 120,0 16 20 25 32 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000 dB Frequency (Hz) 8
- 9. All information subject to change without notice 9 Fig. 8 Directivity according to ISO 16283. Upper and lower curves are the ISO 16283 tolerances -10 -5 0 5 10 100 1000 Directivity Index Frequency (Hz) Fig. 7 Directional response – 1/1 octave Directivity 0,0 20,0 40,0 60,0 80,0 100,0 120,0 0° 30° 60° 90° 120° 150° 180° 210° 240° 270° 300° 330° 31,5 Hz 63 Hz 125 Hz 250 Hz 500 Hz 1 KHz 2 KHz 4 KHz 8 KHz 16 KHz
- 10. All information subject to change without notice Fig. 9 Directivity according to ISO 3382. Upper and lower curves are the ISO 3382 tolerances -10 -5 0 5 10 100 1000 Directivity Index Frequency (Hz) 10
- 11. Company identity Ntek is specialized in products and services for noise and vibration measurement and control, in all applicable acoustic fields. The company has been able to improve in designing, developing and producing solutions that mix simplicity, portability and user-friendly products with excellent quality. Ntek main goal is to supply a qualified service with a complete range of products delivered on time in order to guarantee its customers the chance to focus on their business. To keep this promise we have strongly invested in innovation and production process with monitoring procedures certified by independent primary authority. OUR VISION We believe that acoustics is the basis of wellness and improvement of life quality. It’s for this reason that we develop, innovate and produce equipment inspired to this philosophy. HOW WE WORK Ntek can ensure a high level of service, thanks to modern processes and new laboratories, completely equipped for different operations of design, production, measurement, check and control. INTERNAL LOGISTICS AND STOCK With its new operative location of 500 m2 and its internal stock, Ntek guarantees available products in a short time according to customers’ needs. Today we can handle an order in 48 hours compared with a standard delivery of 45/60 days. The new location is structured to be flexible with logistics activities and in answering efficiently to productive needs of our customers. SUSTAINABILITY Green company, environmentally friendly, aimed to a continuous improvement of quality and safety in industrial processes. Ntek S.r.l. Via Gabrielli 18 10077 San Maurizio Canavese (TO) ITALY www.ntek.it info@ntek.it +39 011 40 53 600