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Summary of Contents for Norsonic nor121
- Page 1 Extension to INSTRUCTION MANUAL SOFTWARE VERSION Introducing: Swept-Sine measurement technique and other new features SOUNDANALYSER...
- Page 3 Introducing: Swept-Sine measurement technique...
- Page 4 Software version 4.0 Introducing SweptSine measurement technique Im121_5Ed1R0Eng Norsonic is a registered trademark of Norsonic AS. All other brand or product names are trademarks or registered trademarks of their respective companies. Every effort has been made to supply complete and accurate in- formation.
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Page 5: Table Of Contents
Quicker instrument switch-off Benefits of using Swept-Sine Save a new default set-up Principles behind the method SMS command for date and time Implementation in Nor121 0 dB reference selection Excitation signal Improved modem connections Measurement of IRs - deconvolution New weather station connection... -
Page 7: Introduction
Contact the factory or your Norsonic representative if you need more information. • Pre-weighting of spectra For description of the sound level meter Nor121 in gen- eral, reference should be made to the main user guide for • Reference tone on recordings the instrument. - Page 8 Nor121 page 2...
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Page 9: General Features
Save a new default set-up The Nor121 was originally designed to save the current The Nor121 contains a default set-up that will always be set-up by switch-off in order to start up again with exactly loaded by turning the instrument on until a new Standard the same set-up. -
Page 10: Db Reference Selection
Nor121 Improved modem connections The Nor121 may be used for long term noise monitoring in a system based on modem connection to the NorXfer version 4.2 software. Earlier versions of the Nor121 occa- sionally had some problems with the output buffer when the modem connection was broken. -
Page 11: Environmental Mode
Instruction manual Environmental mode Pre-weighting of spectra The graphical and numerical displays of frequency spec- The presence of A-pre-weighting is clearly indicated tra within all the reports in the Environmental mode, may in the various displays as all values are followed by a now be viewed via a selectable A-weighting filter. -
Page 12: Noise Criterions (Nc, Nr, Rc)
Version 4.0 of Nor121 provides the standardized NC, NR and RC noise rating criteria, and hence any spectrum measured in the Environmen- tal mode may therefore be evaluated using these criteria. - Page 13 Instruction manual The Noise Criterion evaluation search the highest 1/1-octave band that fits below the applicable noise criterion lines. The evaluation is performed in 1 dB steps. 1/3-octave spectrums are re-calculated into 1/1-octave spectrums prior to evaluation. page 7...
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Page 14: Marker For External Dc Failure
“Annoyance Recorder”. Reference tone on recordings When the Nor121 is used to make true audio recordings of the measured sound it is often necessary for them to be replayed as part of either mediation or legal proceedings. -
Page 15: Pure Tone Mode
Instruction manual Pure tone mode Improved possibilities Pre-set pure tone Standards In the MeasSetup menu, there is now a choice between In the Set-up/Standards menu, there is now a wider range the algorithm specified in the DIN 45 681 (Entwurf 2001) of preset Standards for pure tone analysis. -
Page 16: Building Acoustic Mode
Nor121 Building acoustic mode Spectrum Adaptation Terms The Average Rating Report is now also calculating the Spectrum Adaptation Terms as given in the ISO 717 Standard. These terms are calculated both for airborne and impact sound insulation measurements. When an ex- tended frequency range is used for the measurement the corresponding terms are calculated as well. -
Page 17: Equalizer
Sine excitation when sweep duration parameter has value and quality of measurement results. “Long”. Equalizer implementation characteristics The equalizer implemented in Nor121 is a 21 band equal- izer with one-third-octave bandwidth. The central frequen- cies of filters are at one-third-octave bands’ mid-frequen- cies from 50Hz to 5kHz. -
Page 18: Using Eq With The Pink Noise Excitation - A Cookbook
Nor121 Using EQ with the Swept-Sine excitation Equalizer can be used with both one-third-octave and - a cookbook one-octave band resolution. When used with octave reso- lution, gain is applied to all three one-third-octave bands constituting that octave. Basically the same as with the pink noise excitation ex- cept that the generator can not be started separately and Equalizer gains are saved at instrument switch-off. -
Page 19: Swept-Sine Measurement Technique
2006, which means that sound insulation tests may be performed using this new technique as an alternative to the traditional ISO-140 technique. The Swept-Sine measurement technique is available for all Nor121 units equipped with version 4.x and the new option 14 SweptSine technique. page 13... -
Page 20: Building Acoustics Measurements Using Swept-Sine Technique
Nor121 Building Acoustics measurements using Swept-Sine technique Introduction - Impulse response is also indirectly involved in the What is Swept-Sine technique? classical method with noise excitation as the measured Classical method for the measurement of sound transmis- response to such excitation can be described as a con-... -
Page 21: Benefits Of Using Swept-Sine
Instruction manual Benefits of using Swept-Sine air movement is expressed, sweeps are sometimes the only The international standard ISO 18233: Acoustics - Appli- viable option when measuring impulse responses. cation of new measurement methods in building acous- The measured impulse response is normally the com- tics focuses on use of MLS and Swept-Sine techniques. -
Page 22: Principles Behind The Method
Nor121 Swept-Sine does not require synchronization between nique exploit this approach. With MLS, we simply shoot generator and receiver. For MLS this was the issue as the several pulses and we do it very fast and for several sec- errors in synchronization degrade the measurement. Pre- onds or even minutes. - Page 23 Instruction manual The effect of air fluctuation (wind) and temperature fluctuations is that the speed of sound changes over time. This means that response obtained at lower speed will be stretched in time as it takes more time to gather all the energy.
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Page 24: Implementation In Nor121
Fade-in and fade-out are Nor121, and carefully crafted algorithms enabled imple- applied at beginning and end of the excitation signal to mentation of such an advantageous technique as Swept- protect loudspeaker from transients. -
Page 25: Measurement Of Irs - Deconvolution
In Swept-Sine case, those times are considerably noise ratio of up to 100 dB which is far more then what the shorter then at the classical method. standard requires. Figure 6. Block diagram of implementation in Nor121 page 19... -
Page 26: Setting Up For Swept-Sine Measurement
The lengths of the measured impulse responses (IR) by default. The menu is also accessible by pressing the exceed 10 s. Block diagram of implementation in Nor121 Setup key. is presented in figure 6. It is important to notice that de-... - Page 27 Instruction manual The instrument is equipped with 7 standard setups for Swept-Sine measurements: 1. Impulse Response Measurement, Swept-Sine is used for broadband impulse response measurements which are closely described in second part of this chapter. 2. Reverberation time, Sweep is the setup intended for general measurements of reverberation time. Both channels are used for measurements in one-third octave bands with midband frequencies from 50 Hz to 5 kHz 3.
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Page 28: Level Setup
Nor121 Level Setup Parameter “Sweep Duration” can have three values: Level setup menu is presented in figure 8. It is used to “Short”, “Medium” and “Long”. This parameter together contol the input channels, the frequency range, the with “Frequency range” and “Bandwidth” affect the total measurement duration and the dispaly of results. - Page 29 Instruction manual A Upper range for measurement B One or both channels can be selected for measurement, just as with classical measurement C Excitation type can only be SweptSine. Only this exitation is available in Swept-Sine standard setup. D Details parameter, dispalys group of parameters marked with I on the screenshot E Primary and secondary level range reverberation times, Secondary is measurement if it is not possible to measure primary RT F Defines the distance from estimated level of noise floor to the lower end of the level range from which the reverbera-...
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Page 30: Reverberation Setup
Nor121 Reverberation setup Rating and BGN setup Reverberation setup menu is presented in figure 9. This Please note that parameter “BGN correction” from Rating menu contains three submenus depending on excitation setup menu (displayed in figure 10) is automatically set type. -
Page 31: Making Measurements With Swept-Sine
Instruction manual Making Measurements with Swept-Sine Making measurements using Swept-Sine technique is even simpler than with the classical method, as it is not necessary to measure background noise levels separate- ly. As measurement is usually conducted in accordance with an appropriate standard it is advisable to use stand- ard setups and follow the instructions given in section “Measuring airborne sound reduction between rooms - a cookbook”... - Page 32 Nor121 LEVEL Figure 13. Sequence of displays in Level report page 26...
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Page 33: What Does The Measured Bgn And Snr Mean
Instruction manual A novelty in Swept-Sine based measurements is that Tip: Do not correct for the background noise level! “?” symbol can be displayed with level results. However, Note that Swept-Sine method compensates for the note that it does not have the same meaning as with rever- apparent background noise automatically. - Page 34 Nor121 If only L2 is marked with “?” that means that real differ- Note that the “?” symbols are displayed only after the ence is greater or equal to the measured value. In other whole measurement is finished i.e. when instrument is in words the real value might be higher, but we are not able ENDED state.
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Page 35: Measurement Of High Sound Insulation Values
Instruction manual Measurement of high sound insulation values 2. Use a low generator output level and amplify the sig- One of the advantages of the Swept-Sine technique is nal in the power amplifier. This will reduce the risk for the ability to perform measurements of high sound insula- crosstalk from the generator output to the signal out- tion values and measurements in presence of high back- put. -
Page 36: Technical Specifications
Nor121 Technical One-third-octave bands: Frequency [Hz] RTmin [s] RTmax [s] specifications 0.20 0.14 0.14 0.10 Bandwidth = 1/3 Octaves: 0.09 Sweep duration : “Short”, 60.9 s 0.08 Duration per bandwidth : 2.9 s/one-third-octave-band 0.07 Acquisition duration : 68.92 s 0.06 Start frequency : 38.13 Hz... -
Page 37: Broadband Impulse Response Measurements Using Swept-Sine
.ndf data files are stored and can be transferred to PC 5. Save the measurement on the PC card or instruments for further processing. Note that .ndf is a Norsonic data hard disk using Memory menu file used internally in the instrument. The format used for data storage in an .ndf file is raw data format (without any... -
Page 38: Transferring Measured Ir From The Instrument To A Pc
Nor121 8. Click on the “connect” icon and chose Nor121 as an Figure 16. Echogram of an impulse response measured in Instrument and Local as a Connection Nor121 9. Copy the measurement to My Measurements. If cable is used, do the following: 7. - Page 40 P.O. Box 24 N-3421 Lierskogen Norway Norsonic AS supplies a complete range of instrumentation for acoustics – from sound calibrators, micro- Tel: +47 3285 8900 phones & preamplifers; via small handheld sound level meters to advanced, yet portable, real time analysers, Fax: +47 3285 2208 but also building acoustics analysers and complete community, industry and airport noise monitoring systems.
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