User Manual Real Time Octave Band Analyzer Model 407790A
Table of Contents 1. INTRODUCTION ................................................................................................ 3 1.1 Instrument Care ............................................................................................ 4 1.2 Features ........................................................................................................ 5 2. DESCRIPTIONS ................................................................................................ 6 2.1 Meter Description........
1. Introduction Congratulations on your purchase of the Extech 407790A Real Time Octave Band Analyzer. This auto ranging Type 2 integrating sound level meter features 1/1 and 1/3 Octave Band real‐time noise analyses. The 407790A offers five measurement parameters: SPL (Sound Pressure Level), Leq (Equivalent Continuous Sound Pressure Level), SEL (Sound Exposure Level), Lmax (Maximum Sound Pressure Level), and Lmin (Minimum Sound Pressure Level).
1.1 Instrument Care Do not attempt to remove the mesh cover from the microphone as this will cause damage and affect the accuracy of the instrument. Protect the instrument from impact. Do not drop it or subject it to rough handling. Transport it in the supplied carrying case. Protect the instrument from water, dust, extreme temperatures, high humidity and direct sunlight during storage and use.
1.2 Features The Sound Level Meter complies with the requirements of IEC 61672‐1:2003 standard for a Class 2 instrument. See specifications section for more applicable standards that apply to this meter. 1/1 octave band analysis from 31.
2. Descriptions 2.1 Meter Description Refer to the diagram below for the following descriptions. 1. Windscreen 9. 2. Microphone 10. 3. Display 11. 4. Operation keys 12. 13. 5. 6VDC adapter jack 14. 6. DC analog output jack 15. 7. AC analog output jack 8. Comparator output jack LA 65.2 dB OFF ON LIGHT W 60 40 125 500 2k 8k L W CONTRAST 20 Hz 31.
2.2 Operation Buttons START/STOP button Press to start or stop for recording the sound pressure measurement. PAUSE/CONT button Press to temporarily pause ( ) a measurement) or resume () measurement. M button Press to scroll through and select different processing modes. LEVEL Press to select the level range for measurement. The following five settings are available. 20 to 90 dB, 20 to 100 dB, 20 to 110 dB, 30 to 120 dB, 40 to 130 dB.
/ Press to move the octave frequency band marker during frequency analysis. + / Press to select and set items in various menu screens. Holding the buttons down will cause faster scrolling. FREQ WEIGHT TIME button The FREQ WEIGHT selects the frequency weighting for the main channel. “A” weighting (A), “C” weighting (C), and flat frequency response (Z). The TIME WEIGHT selects the time weighting function for the main channel.
2.3 Display Screen Measurement in progress symbol Memory Trigger mode Store mode Mode of analysis USB link status Elapsed time Address Bar graph Level range Overload indication Underrange indication Sub channel level display Main channel Frequency weighting Sub channel Time weighting Time weighting Frequency weighting Main channel level display Current time Power status Comparator ON Manual store full indication Current date Auto store full indication 1.
8. Address: Displays current number of data surveys stored in memory. 9. Bar graph: Displays the sound level as a bar graph. (The display is updated every 100ms) 10. Level range: Displays the upper and lower limit of the bar graph. Can be changed with the LEVEL button. 11. Under‐range indication: When a signal is under‐range the UN symbol will appear on the screen. Use the LEVEL button to decrease the level range setting.
2.4 Analysis screen An example for the 1/1 & 1/3 OCT analysis screen is shown below. Use the and buttons to move the cursor to the target frequency band. 1/1 and 1/3 analysis screen 11 407790A-en-US_v2.
2.5 Numeric Display screen Example for 1/1 OCT, 1/3 OCT, and 1/1 & 1/3 OCT analysis screen are shown below. Use the and buttons to view a frequency that is not displayed. 12 407790A-en-US_v2.
3. Measurement Preparation and Setup 1. Battery installation: Remove the rear battery cover as shown below and insert (4) 1.5V ‘C’ size alkaline batteries. Take care to observe battery polarity. Replace the battery cover. 2. Battery replacement: When the battery voltage drops below operating voltage, battery symbol flashes on the display. 3. AC adaptor connection: Insert the adaptor in the DC 6V jack on the side panel.
5. Continue pressing the above buttons to scroll through and set each option for date and time. The meter will continue to scroll through setup for date Y/M/D and then the time settings h/m/s. 6. When the settings are correct, press the button to exit the setting mode. The clock will start running with the new settings. 7. Press MENU button to return to the measurement screen. Note: The clock has an error of about 1 minute per month.
3.2 SD Memory Card Measurement data can be stored on a removable SD memory card for later use. Note: Power OFF the meter before inserting or removing the memory card. Use only a 4GB micro SD card. Removing SD card or powering the meter off while data is storing to the card can cause internal data to be destroyed. 1. 2. Insert the card taking care to observe the correct orientation. Push the card in carefully, until it is properly sealed. To remove, push the card.
3.4 Sub Channel Settings To access the sub menu setting press the following buttons. 1. Press the MENU button to enter the menu list screen. + / 2. Use the buttons to select “G). Sub Time Weight” then press button. + / button to select the desired time weighting 3. Use the F, S, τ (10ms) or I (Impulse 35ms), then press button. + / buttons to select “H). Sub Freq Weight” then press button. 4. Press the + / buttons to select the desired frequency weighting A, C or Z, then press 5.
3.5 Selecting the Lmax/Lmin type Band ‐ (Band maximum/band minimum): The analysis result applies to the point where the level for each frequency band was maximum or minimum within the sampling period. AP ‐ (All‐pass maximum/all‐pass minimum): The analysis result applies to the sub channel all‐pass and band‐pass level values taken at the point where the all‐pass level in the main channel was maximum/minimum within the sampling period.
3.6 Comparator Output Operation The comparator output is an open collector output that can be used to control external equipment. 1. Press the MENU button to enter the menu list screen. + / 2. Use the buttons to select “J). Comparator” then press button to display the ON/OFF setting. + / 3. Press the buttons to select “ON” then press button. + / buttons again to select “1). Comparator Level”. Set the desired level 4. Press the then press button.
AP AP AP AP 19 407790A-en-US_v2.
Comparator output: In the SLM mode, only the AP is selected as comparator band. In the 1/1 OCT mode, only the AP or 1/1 octave band is selected as comparator band. Comparator output: Open‐ collector output; band‐level determination; Max. applied voltage: 24VDC; Max. drive current: 50mADC 1 2 3 1. Comparator signal output continues for 0.5 seconds after the signal crosses the threshold level 2. Comparator Level 3. Time 20 407790A-en-US_v2.
3.7 Trigger Mode Setup and Operation A measurement can be initiated by one of three triggers: time trigger (time‐controlled triggering), level trigger (sound level controlled triggering), and external trigger (triggering by an external signal). Level trigger 1: Measurement starts when the trigger level is exceeded and ends after the measurement time. The trigger level is valid at any time. Setting items: Trigger Slope Type: +, ‐ Trigger Level: 25 to 130dB, 1‐dB steps. Trigger Band: MAIN AP/31.
3.7.1 Trigger Setup 1. Chose trigger operation [off, Level 1, Level 2, External, or Time]. 2. Set the Trigger Band: AP or Octave band frequency 3. For Level 1 and 2: chose the Trigger level in dB. 4. External Trigger, chose slope (+ or ‐) AP 3.7.2 External Trigger Setting 1. Press the MENU button to enter the menu list screen. + / 2. Use the buttons to select “K). Trigger” then press the button. + / 3. Use the buttons to select “EXT” then press the button. 4.
+ / 4. Use the buttons to select “2). Trigger Band” then press the button. + / 5. Use the and buttons to set the value to AP then press the button. + / 6. Use the buttons to select “3). Trigger Time” then press the button. + / and buttons to set the value of the reoccurring trigger timer 7. Use the Hour:Minute:Second then press the button. - 8. Press the MENU button to return to the measurement screen. AP AP 3.7.
+ / 7. Use the buttons to select the desired trigger band then press the button. + / 8. Use the buttons to select “4). Slope Type” then press the button. + / 9. Use the buttons to select the desired trigger slope + or Slope‐. Then press the button. Note: For LEVEL 2 trigger, ignore the slope setting and only use the Slope+ trigger. 10. Press the MENU button to return to the measurement screen. 11. Press the R button on the meter to start automatic recording.
4.Measurements All processing functions provided by the meter (Leq, SEL, Lmax, Lmin, Ln) are carried out simultaneously. For example, when equivalent continuous sound level measurement is selected, the sound exposure level and percentile level are also determined. 4.1 Sound Level Measurements 1. Press the power button to power on the meter. After the power‐on screen displays the SLM measurement screen will appear.
4.2 SEL, Leq, Lmax, Lmin, LN Measurements 1. Power on the meter. After the power‐on screen displays, the SLM measurement screen appears. 2. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For normal sound level measurements, select the “A” setting. When “C” (C‐Weighting) is selected, the equivalent continuous sound pressure level (LCeq) is measured. 3. Use the FREQ WEIGHT TIME button to select the time weighting characteristic.
8. Press the button to exit the measurement time setting. 9. Press MENU button to return to the measurement screen. 10. Press the START/STOP button to start the measurement. Previously measured values will be cleared. While the measurement is in progress, the symbol will flash and the elapsed time will display on the screen. When the measurement time has elapsed, the measurement is terminated automatically. To terminate the measurement before the allocated time, press the START/STOP button.
4.3 Sound Level and Octave Band Analysis Measurement 1. With the power ON wait until the SLM measurement screen appears on the display. 2. Use the SLM 1/1 1/3 button to select the desired 1/1 OCT, 1/3 OCT or 1/1 & 1/3 OCT band or SLM measurement screen. 3. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For normal sound level measurements, select the “A” setting. 4. Use the FREQ WEIGHT TIME button to select the time weighting characteristic.
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4.4 Sound Band ‐ Leq, SEL, Lmax, Lmin and LN Analysis Measurement 1. Power on the meter and wait until the SLM measurement screen appears. 2. Use the SLM 1/1 1/3 button to select the desired 1/1 OCT, 1/3 OCT or 1/1 & 1/3 OCT band or SLM measurement screen. 3. Use the FREQ WEIGHT TIME button to select the frequency weighting characteristic. For normal measurements, select the “A” setting. 4. Use the FREQ WEIGHT TIME button to select the time weighting characteristic.
If the indication “UN” is shown, the processed data include data where the sound level signal caused an under‐range condition. 13. Press the M button to cycle through the Lp Leq LE (SEL) Lmax LminL05L10L50L90L95 measured value on the screen. Pressing the GRP/NUM button switches the measurement screen between graph and numeric display. In graph display, use the and buttons to move the cursor to the desired frequency band.
5. Storing Data to Memory The meter can store measurement data in the internal memory or on a micro SD card. There are three different ways of storing data, as listed below. Manual: In this mode, the operator stores the measured sound level data and processed value data into the memory manually. Press the R record button to cause the current sound level and processed values derived from the measurement, as well as the measurement parameters and time of recording to be recorded in a single measurement.
Selecting FLASH will store the data in the internal memory. Selecting SD Card will store the data on the SD CARD. + / buttons to select “C). Store Mode” then press the key. 5. Use the + / 6. Use the buttons to select “MANUAL” then press the key. 7. Press the MENU button to return to the measurement screen. 8. Press the R button. The sound level will be recorded. If processing was being carried out, the processed values at the point where the R key is pressed will also be recorded.
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5.2 Recalling Manually Stored Data 1. Power on the meter. 2. Press the MENU button to enter the menu list screen. + / 3. Use the buttons to select “M). Recall” then press the button. + / buttons to select the store address whose data you want to recall, then 4. Use the press the button. The data stored in memory will display. - 5. In analyzer mode, the GRP/NUM key can be used to switch between numeric display and graph display. + / 6.
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5.3 Erasing Manually Stored Data 1. Press the MENU button to enter the menu list screen. + / 2. Use the buttons to select “L). Clear Record” then press the button. + / 3. Use the buttons to select “MANUAL” then press the button. A confirmation message will appear. To erase the data, press the button. To cancel the process, press the MENU button. Note: you can also erase the manual memory from the software. AP AP AP AP 37 407790A-en-US_v2.
5.4 Auto 1 Memory Storage Memory Store Continuously store the current measured data as 1 set, at preset record interval times. 1. Power on the meter. 2. Press the MENU button to enter the menu list screen. + / 3. Use the buttons to select “B). Storage” then press the button. + / 4. Use the buttons to select “FLASH” or “SD Card” then press the button. Selecting FLASH will store the data in the internal memory. Selecting SD Card will store the data on the SD CARD. + / buttons to select “C).
To stop the process earlier, press the START/STOP or the R key. When the store is completed or stopped, the memory block address is incremented by one step. Note: When memory block address 250 is reached, the AFul symbol is displayed and no more data can be stored. The AUTO recording of data can only be read by PC, it cannot be recalled by the meter. 3 1 2 4 5 1. Measurement time (duration of test) 2. Measurement time (duration of test) 3. Measurement Stop or Memory full is reached (AFu) 4.
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5.5 Auto 2 Memory Storage Memory Store Continuously store the processed data at a preset measurement integrated time. 1. Power on the meter. 2. Press the MENU button to enter the menu list screen. + / 3. Use the buttons to select “B). Storage” then press the button. + / 4. Use the buttons to select “FLASH” or “SD Card” then press the button. Selecting FLASH will store the data in the internal memory. Selecting SD Card will store the data on the SD CARD. + / buttons to select “C*).
5.6 Erasing Auto Stored Data 1. Press the MENU button to enter the menu list screen. + / 2. Use the buttons to select “L). Clear Record” then press the button. + / 3. Use the buttons to select “Auto” then press the button. A confirmation message appears. To erase the data, press the button. To cancel the process, press the MENU button. Note: you can also erase the manual memory from the software. 42 407790A-en-US_v2.
6. Software Download and Installation The 407790A software is available for free download from the WWW.EXTECH.COM web page, located under the Software downloads section. SAVE the 407790A software to your PC. Perform an “Extract All” to unZIP the files. Run ExtechInstaller.exe to install the software. There is no USB driver, as the meter attaches as a Human Interface device. The software has a Help manual available to understand the full operation. 43 407790A-en-US_v2.
7. Sound Pressure Level ‐ Technical notes 1. The decibel (dB) The range over which the human ear responds to sound pressure (noise) is extremely large; in Pascals (Pa) it is 20Pa (the threshold of hearing) to 100 Pa (the threshold of pain). The measurement of sound pressure has been made more convenient by the use of the decibel, which is logarithmic. However, decibels are non‐linear and therefore cannot be added together.
8. Calibration Calibrating the 407790A requires an acoustical calibrator such as the Extech Model 407766 or 407744 that can provide 94.0dB or 114dB at 1kHz. 1. Set the power switch to the OFF position. 2. + and buttons then turn the power ON until CAL appears on the Press and hold the screen. 3. Insert the microphone into the opening of the acoustical calibrator. 4. Switch the calibrator ON (1kHZ 94dB or 114dB) 5.
9. Specifications Applicable Standards: IEC 61672‐1: 2013 Class 2, IEC 61260‐1: 2014 Class 2, ANSI S1.11: 2004 Class 2, ANSI S1.4: 1983 Type 2, ANSI S1.43: 1997 Type 2 Measurement functions: Simultaneous measurement of main channel and sub channel. Frequency weighting and time weighting are set independently for main and sub channel.
Time weighting: Main channel: Fast (125ms), Slow (1000ms), 10ms, Impulse (35ms) Sub channel: Fast (125ms), Slow (1000ms), 10ms, Impulse (35ms) Measurement level range: A‐weighting: 25 to 130dB C‐weighting: 33 to 130dB Z‐weighting: 38 to 130dB Total meter range: 25dB to 130dB (A‐weighting, 1kHz) Linear operating range: 90dB Level Range: 20 to 90dB, 20 to 100dB, 20 to 110dB, 30 to 120dB, 40 to 130dB Sampling cycle: 20.
Data recall: Allows viewing of the manually stored data. AC output: 1 Vrms at FS (full scale); Output impedance approx. 5kΩ; Load impedance ≥100kΩ DC output: 10mV/dB; Output impedance approx. 5kΩ; Load impedance ≥100kΩ External trigger input: Detection of 0 to 5V logic‐ level signal, falling edge trigger, pulse width 1ms or more USB: Allows connection to a computer as storage device, or use a communication device for unit control via communication commands. Power: Four (4) C size 1.
10. Warranty FLIR Systems, Inc. warrants this Extech Instruments brand device to be free of defects in parts and workmanship for one year from date of shipment (a six month limited warranty applies to sensors and cables). If it should become necessary to return the instrument for service during or beyond the warranty period, contact the Customer Service Department for authorization. Visit the website www.extech.com for contact information.
