CEL-621 Integrating Environmental Sound Level Meter

Many environmental noise measurements require a complete knowledge of the variable noise level climate over a representative period of time. The CEL-621 Integrating Environmental Sound Level Meter is designed to satisfy this need as a short term measurement instrument. It can measure the popular max, min, peak and time average levels plus up to 5 statistical or percentile result for the overall run.

The wide 120 dB dynamic range means that the user does not need to worry about changing the input range settings as it will always be on the right range. The provision of the three popular frequency weightings and the three time weighting enable many different measurements to be taken by new and experienced users alike to correctly characterize the noise.

Applications

For measurement of simple noise levels the instantaneous sound pressure level is often adequate. However, in many outdoor situations the noise levels are too variable or change too quickly to estimate the average level or exceedance levels correctly. The CEL-621 is designed to assist in the correct description of these difficult noise situations by providing the time average noise level with the 3, 4 and 5 dB exchange rates. Changing noise levels are properly integrating into the overall time average answer and displayed as the Leq (with Q=3). 5% LN values (10%, 50%, 90%, 95% and 99%) are calculated and stored from the instantaneous sound levels. This enables the CEL-621 to correctly assess changing noise levels and provide the appropriate result for many short term community noise level surveys. Additional octave band filters in the B or C version of the CEL-621 provide for a comprehensive frequency analysis of tonal noise levels for noise control applications.

Benefits

• Wide dynamic range from 20 to 140 dB on single span
• A, C and Z simultaneous frequency weightings
• Slow, fast and impulse rms time responses
• Large 240 x 320 pixel color ¼ VGA graphic display
• Easy to use menu structure
• Integrating capability for time average values plus peak
• Available with 5 statistical LN% values, measured for broadband levels
• Available in ASNI/IEC class 1 and class 2 accuracy
• Available as broad band, octave or third octave band models
• Storage of all results simultaneously in a huge non-volatile memory
• Available as complete measurement kits with acoustic calibrator and case

Specifications

Accuracy	ANSI S1.4 & S1.43, IEC 61672-1, 2002-5 Filter comply with ANSI S1.11 and IEC 61260
Frequency Weightings	A, C & Z, unweighted
Time Weightings	Slow, Fast, Impulse
Microphone Type	Removable ½" free field electret microphone on fixed preamplifier
Reference Conditions	68F air temperature, 65% rH, 1013 mbar atmosphere pressure
Measurement Range	20 to 140 dB
Noise Floor (A weighted dB)	< 25, Class 1 < 30, Class 2
Dynamic Range on single measurement span (dB)	120 dB
Displayed Parameters Always Available on All User Available Screens	Instantaneous level - Lp, peak level Lpk
	Maximum level - Lmx
	Minimum level - Lmn
	Average levels, Leq, LDOD, Lavg, Ltm3, Ltm5
Display	Type: 240 x 320 full color dot matrix LCD screen including real time analog bar graph
	Resolution numeric (dB) - 0.1
	Resolution graphical (dB) - 1
Update Rate for Display	0.5 seconds
Displayed Time Span for Time History Chart	Last 1 to 5
Displayed time span for time history chart	Last 60 seconds
Octave/third Band Measurements	Complete spectrum plus A & C & Z broad band levels
Frequency analysis measurements - Octave & Third Octave as options in B & C Versions	11 octave bands 16 Hz to 16 kHz 33 third octave bands from 12.5 Hz to 20 kHz
Measurements made in Oct (1/3 oct) band mode include	Lmx and Leq with selected freq and time weightings
Reset of max/min/average level from key press by user	Yes with non-decaying max/min hold
Duration Timer for Run	Yes from 00:00:01 to 24:00:00 to 1 sec/resolution
Displayed Time Span for Time History Chart	Last 60 seconds
Measurements Made in Octave Band Mode Include	Lmx and Leq with selected freq and time weighting
Reset of Max/min/average Level from Key Press by User	Yes with non-decaying max/min hold
Calibration Method	Automatically recognized by meter
Signal Detected when Calibrator Placed Over Microphone at 1 kHZ Frequency	Calibration level set to 114.0 or 94.0 dB with ± 1 dB span and 0.1 bB resolution
External Power Option	Yes via Universal CEL-PC18 Unit
Analog Outputs	AC and optional DC via 2.5 mm jack socket
AC Output Characteristics	About 0.85V RMS FSD output on selected sound level measurement range. Minimum load impedance 22kΩ
DC Output Characteristics	0 to 1.3 VDC for FSD on selected range. Output corresponds to selected frequency and time weighting. 2kΩ output impedance
Digital Output	USB 2.0 format of instantaneous sound level via "mini A" USB
Digital Output Characteristics	Instantaneous SPL output, software required, as per selected frequency and time weighting
Temperature Range	14 to 122°F, Class 1 32 to 104F, Class 2
Effect of Humidity	Less than ±0.5 dB over the range of 30 to 90% RH non condensing
Operating Pressure Range	650 to 1080 mbar
Batteries	3 x AA alkaline or rechargeable types
Battery Life	Up to 12 hours without backlight
Dimensions	2.8 x 9.0 x 1.2"
Weight	10.1 ounces
Tripod socket for fixed measurements	Yes via standard camera thread, 1/4" size
Operator Controls	Buttons for power on/off and 2 x context sensitive menu selection + 4 navigation and confirm buttons
Screen Languages for Display	English, French, German, Italian, Spanish menu selectable

Ordering Information

For pricing, please call AFC International at 1-800-952-3293, 219-987-6825 or fax 219-987-6826 or email sales@afcintl.com.

Downloads

CEL-621 Integrating Environmental Sound Level Meter Literature

CEL-120 Acoustic Calibrator Literature