User manual NADY ASM-2

[. . . ] For the longest life and best performance, we recommend an alkaline battery. Open the battery compartment cover by pressing both sides at the lower striped portion and lifting the bottom. Insert a battery into the compartment as indicated by the polarity markings (+ and -) marked inside. If the meter shows a reading in the red BATT TEST region, the battery is still good. [. . . ] This makes it easy to use the meter with auxiliary recording or test equipment. CAL(CALIBRATION) Your meter has been accurately calibrated at the factory and normally will not require further adjustment. If necessary, an audio professional can use the CAL hole on the meter with special equipment, including a sound generator, to calibrate it. MAKING MEASUREMENTS Important: · Do not hold the meter directly between you and the sound source, as this might produce an error of several decibels in the frequency range above 100 Hz. Position the meter so an imaginary line between you and the meter is perpendicular to a line between the meter and the sound source. The microphone and meter movement are fragile and might be damaged if the instrument is dropped. Do not operate the meter at a range setting that causes "pegging" of the needle. Follow these steps to select the desired response, weighting, and range. Set RESPONSE to FAST if the sound source you want to measure consists of short bursts or if you want to measure only peak values. Or, set RESPONSE to SLOW if you want to measure average sound levels. Set WEIGHTING to A if you want to measure noise level or C if you want to measure sound levels of musical material. Set RANGE to the highest setting(120 dB)then adjust it downward until there is significant deflection of the needle. v for the greatest accuracy , always use the lower of any two possible settings. For example, if RANGE is set to 80 dB and the meter reads around -5 , reset RANGE to 70 dB so the meter reads +3, for an actual sound level of 73 dB. Important: For meaningful readings, any particular sound to be measured must be at least 10 dB louder than the background noise level. While taking measurements, minimize the effect of your body's presence. When the sound is coming mainly from one direction, the level reading might be significantly affected by reflections from your body. For the most accurate readings and the best polar response, point the meter's microphone toward the sound source when possible. Sound Level (dB) Maximum Duration (A- Weighting, SLOW Per Day(hours) CHECKING NOISE LEVELS response) This chart, gathered from Federal, state, and local agencies, shows standards for just how 90 8 much noise is acceptable. Noise is inevitable in almost any environment. Depending on the level and duration, noise can be a minor irritant, a definite disturbance, or even a threat to your hearing. To use your meter to check noise levels, set WEIGHTING to A and RESPONSE to SLOW. Take measurements at several points in the test area, with the meter positioned properly. 92 95 97 100 102 105 110 115 6 4 3 2 1 1/2 1 1/2 1/4 or less CHECKING ROOM ACOUSTICS The size, shape, and furnishings of a room can have a tremendous effect on a home theater Department of Labor Noise Regulations. A "hard" room with bare surfaces tends to exaggerate treble response, sometimes giving the music a strident quality. A "soft" room with curtains, over-stuffed furniture, carpet, etc. [. . . ] Besure to consider this when you use a test recording that includes tones at the extreme high end of the audio spectrum. Permissible noise exposures. Extracted from U. S. SPECIFICATION Range: Switch Setting Range of Measurement 60 dB 50-66 dB 70 dB 60-76 dB 80 dB 70-86 dB 90 dB 80-96 dB 100 dB 90-106 dB 110 dB 100-116 dB 120 dB 110-126 dB Load Impedance: 10 kohm minimum Distortion: Less than 2% at 1 kHz, 0. 5-volt Microphone: Electret condenser omnidirectional becoming slightly directional with increase in frequency Battery: One 9-volt rectangular type Accuracy: ±2 dB @ 114 dB Standard: 0 dB = 0. 0002 µbar Weighting: A and C Response: Fast and Slow Signal Output: 1. 0 volt (peak) minimum into open circuit, with full-scale meter deflection at 1 kHz Battery Check: Tests "good" from 7. 0 To 10. 5 volts Expected Battery Life: 110 working hours (alkaline battery) Size (HWD): 6. 25" x 2. 43" x 1. 75" (160 x 62 x 44 mm) Weight: 6. 6 oz (about 185 grams) Specifications are typical; individual units might vary. Specifications are subject to change and improvement without notice. SERVICE (U. S. ) Should your Nady ASM-2 Sound Level Meter require service, please contact the Nady Service Department via telephone at (510) 652-2411 or e-mail to service@nady. com for a Return Authorization (R/A) Number and a service quote (if out of warranty). Make sure the R/A Number is clearly marked on the outside of the package and enclose a cashier's check or money order (if not prepaid with a credit card). Ship the unit prepaid to: Nady Systems, Inc. , Service Department, 6701 Shellmound Street, Emeryville, CA 94608. [. . . ]