Sound Level Meter recorder, data logger

Specifications : with CE approval

Standard Applied:	IEC651 Type 2, ANSI S1.4 Type 2
Frequency Range	31.5Hz ~ 8KHz
Measuring Level Range	30 ~ 130dB
Frequency Weighting	A/C
Microphone	1/2 inch electric condenser microphone
Display	LCD Back Light Function
Digital Display	4 digits , Resolution: 0.1dB, Display Update: 0.5 sec
Analog Display	50 segment Bar graph, Resolution, Resolution: 1dB, Display update: 50mS
Time Weighting	FAST (125mS); SLOW(1 Sec)
LEVEL Range	Lo: 30 ~ 80dB ; Med: 50~ 100dB, Hi: 80~ 130dB; Auto Range : 30~ 130 dB
Accuracy	±1.5dB (under reference condition at 94dB 1KHz)
Measuring Level Range	30 ~ 130dB
Dynamic Range	100 dB
Over and Under range Indication Function	"OVER" is displayed, while input is more than upper limit of range. ; " UNDER" is displayed, while input is less than lower limit of range.
MAX/MIN Hold	Hold Reading the Maximum and Minimum Value
AC Output	1V rms at FS (Full Scale), output impedance : Approx. 100 Ω
DC Output	10mV/dB, Output impedance approx. 1K Ω
Auto Power Off	30 minutes if no operation
GENERAL
Power Requirement:	One piece 9V battery NEDA 1604
Power Life	About 50 Hours (Alkaline battery)
AC Adapter (option)	Voltage 9VDC (8~ 15 V DC Max) ; Supply current : > 30mADC
Operation Temperature	0 to 40 ºC (32 to 104 ºF)
Operation Humidity	10 to 90% RH
Storage Humidity	10 to 75% RH
Weight:	10 oz(285g)
Accessories:	9V battery, Carrying case, calibration screwdriver , 3.5Ø plug, windscreen and owners manual, RS-232 cable (USB Cable Optional) .
Tripod Connection Hole	Able to connect Camera Tripot Stand

Software operation illustration of

Digital sound level data logger TECPEL DSL-331

Q & A:

We own one of your Tecpel 331 sound data loggers which we used to measure the noise levels in patients rooms. The recording range was set 30-130 dBa, in fast recording mode. We had measurements of 28 dB despite the range of 30-130 dB. Could you please explain how this happen? Our findings will be published in a scientific journal hence we may need to explain this to reviewers.
Your help is much appreciated

Answer: Our design can measure starting from 25 db but 30 dB is the

limit of our published specification. Therefore, it is possible to have 25 ~ 29 dB, if your environment

is quite calm in a closed room.

Video for operatiing sound level logger of TECPEL DSL-331