User's Guide Digital Sound Level Meter MODEL 407736 • 1.5 dB accuracy meets ANSI and IEC 651 Type II standards • A/C weighting & Fast/Slow response • Built-in calibration check • 0.1dB resolution Introduction Congratulations on your purchase of the Extech Model 407736 Digital Sound Level Meter. This meter is shipped fully tested and calibrated and, with proper use, will provide years of reliable service. Meter Description 1. 2. 3. 4. 5. 6. 7. 8. 9. Microphone LCD display POWER OFF & RANGE select switch RESPONSE & HOLD select switch A/C weighting and Calibration switch Calibration adjust screw for 94dB Reset key (resets max hold reading) AC/DC analog output 3.5mm phone jack Battery compartment and Tripod mount are located on the back of meter 1 2 4 5 3 7 6 Lo = 35 ~ 100dB HI = 75 ~ 130dB 8 9 Measurement Considerations 1. Wind blowing across the microphone adds extraneous noise to the measurement. Use the supplied windscreen to cover the microphone when applicable. 2. Calibrate the instrument before each use if possible. Especially if the meter has not been used for a long period of time. 3. Do not store or operate the instrument in areas of high temperature or humidity. 4. Keep meter and microphone dry. 5. Avoid severe vibration when using the meter. 6. Remove the battery when the meter is to be stored for long periods of time. 2 407736 V2.0 5/08 Meter Operation Quick Start 1. Power the meter by moving the RANGE switch to the LO or HI position. The meter will begin displaying sound levels. If the LCD does not display, check that the battery is good. 2. Place the meter on a tripod or hold the meter in hand facing the microphone toward the source of the sound to be measured. Note that the tripod mount is on the back of meter. 3. View the measurement on the meter’s LCD. An indication of ‘OVER’ means that the measurement is out of range. Select another measurement range in the event of an over-range condition. ‘A’ and ‘C’ Frequency Weighting Use the FUNCT (function) switch to select ‘A’ or ‘C’ frequency weighting. Use ‘A’ weighting to have the meter simulate the response of the human ear (the human ear boosts and cuts sound levels at specific points over the frequency spectrum). ‘A’ weighting is used for environmental measurements, OSHA regulatory testing, law enforcement, and workplace design. Select ‘C’ weighting for flat response measurements (no boosting or dampening across the frequency spectrum). ‘C’ weighting is suitable for the operational maintenance and analysis of machinery, motors, pumps, engines, etc. FAST/SLOW Response Time Use the RESPONSE switch to select FAST (125 ms) or SLOW (1 second) response time. The application at hand (and any directives or standards) will dictate which response to select. For example, most hearing conservation or OSHA related testing is done using SLOW mode and ‘A’ weighting. MAX HOLD In this mode, the meter only updates the LCD when a higher reading than the one presently on the display is detected. Select MAX HOLD using the RESPONSE switch. The LCD shows ‘MAX HOLD’ in this mode. Press RESET to reset the MAX HOLD reading. Analog Outputs The meter includes an AC and a DC analog output for use with chart recorders, dataloggers, etc. The AC output is 0.65V rms full scale and the DC output is 10mV per dB. The 3.5mm output jack is located on the right side of the instrument. Use a stereo miniplug as shown in the diagram below to connect the meter to a datalogger or other recorder. 1. 2. 3. 1 Sleeve: ground Ring: DC out Tip: AC out 2 3 Calibration Check This meter provides a built-in calibration adjustment. The calibration adjustment potentiometer is located on the front panel beneath the FUNCT switch. Put the FUNCT switch to the CAL 94dB position and adjust the potentiometer for a display of exactly 94dB. For calibration with an external sound level calibrator, refer to the instructions accompanying the calibrator. 3 407736 V2.0 5/08 Battery Replacement When the low battery message appears on the LCD replace the 9V battery as soon as possible. The battery compartment cover resides at the bottom, rear of the meter. Slide the battery compartment cover off, change the battery, and replace the compartment cover. Typical ‘A’ weighted Sound Pressure Levels dBA 140 50HP Siren (100') 130 Jet takeoff (200') 120 110 Riveting machine 100 Subway (20') 90 Pneumatic drill (50') 80 Vacuum cleaner (10') 70 Large store 60 Small office 50 Night residential area 40 Whisper (5'0) 30 20 Chain saw Boiler room Freight train (100') Speech (1') Large Office Residence Sound studio 10 Threshold of hearing 0 Warranty EXTECH INSTRUMENTS CORPORATION (A FLIR COMPANY) warrants this instrument 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 at (781) 890-7440 ext. 210 for authorization or visit our website www.extech.com for contact information. A Return Authorization (RA) number must be issued before any product is returned to Extech. The sender is responsible for shipping charges, freight, insurance and proper packaging to prevent damage in transit. This warranty does not apply to defects resulting from action of the user such as misuse, improper wiring, operation outside of specification, improper maintenance or repair, or unauthorized modification. Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct, indirect, incidental or consequential damages. Extech's total liability is limited to repair or replacement of the product. The warranty set forth above is inclusive and no other warranty, whether written or oral, is expressed or implied. 4 407736 V2.0 5/08 Specifications Display Display update rate Microphone Measurement Bandwidth Dynamic range Measurement Range Frequency weighting Applicable standards Accuracy / Resolution Maximum Hold decay time Response time Built-in calibration check AC Analog output 3-1/2 digit (2000 count) LCD 0.5 seconds 0.5” Electret condensor 31.5Hz to 8KHz 55dB 35 to 130dB (Low: 35 to 100; High: 65 to 130dB) ‘A’ and ‘C’ (selectable) IEC-651 & ANSI S1.4 Type 2 ± 1.5dB / 0.1dB <1dB / 3min Fast: 125 milliseconds / Slow: 1 second 1KHz internal sine wave @ 94dB DC Analog output 10mVDC / dB; 100Ω output impedance (approx). 9V Battery 50 hours (typical); Low battery indicator alerts user o o 32 to 104 F (0 to 40 C) 10 to 90% RH 9.45 x 2.68 x 1” (240 x 68 x 25mm) / 6.75oz (210g) Power Battery life Operating temperature Operating humidity Dimensions/weight 0.65VAC rms (full scale); 600Ω output impedance Support line (781) 890-7440 Technical Support: Extension 200; E-mail: [email protected] Repair & Returns: Extension 210; E-mail: [email protected] Product specifications subject to change without notice For the latest version of this User Guide, Software updates, and other up-to-the-minute product information, visit our website: www.extech.com Extech Instruments Corporation, 285 Bear Hill Road, Waltham, MA 02451 Calibration and Repair Services Extech offers repair and calibration services for the products we sell. Extech also provides NIST certification for most products. Call the Customer Care Department for information on calibration services available for this product. Extech recommends that annual calibrations be performed to verify meter performance and accuracy. Copyright © 2008 Extech Instruments Corporation (a FLIR company) All rights reserved including the right of reproduction in whole or in part in any form. 5 407736 V2.0 5/08 6 407736 V2.0 5/08