MEWOI-TW408B Class 1,1/1OCT,1/3OCT,Sound Level Meter,SONÔMETRO,Decibelímetro Digital

  • Name:
    MEWOI-TW408B Class 1 Sound level meter
  • Model No.:
  • Main Features:
    MEWOI-TW408B Class 1,1/1OCT,1/3OCT Sound Level Meter,SONÔMETRO,Decibelímetro Digital
  • Price
OEM/ODM Testing Instruments Manufacturer

Contact Us for QuotationEmail:mewoi@mewoi.comWhatsapp: +8618620373879

MEWOI-TW408B Class 1,1/1OCT,1/3OCT,Sound Level Meter,SONÔMETRO,Decibelímetro Digital


MEWOI-TW408A,TW408B,TW409A,TW409B are new generation octave sound level meter,they update the dual core (DSP+ARM) architecture to single chip ARM with float point unit, and update all fix--point calculation to floatpoint calculation which significantlignificantlyy improves the accuracy and and stability. Re-design analog front end circuit also lower the noise floor and linear range of product.

MEWOI-TW408A,TW408B are Class 1 , and TW409A,TW409B are Class 2. Both instruments have ccertificated by the China CPA (Certification of of Pattern Approval)  and CMC (China Metrology Certification)


1,Class 1 MEWOI-TW408A,TW408B ) and Class 2 (MEWOI-TW409A,TW409B) sound level meter
2,Comply with IEC 61672 1:2013, ANS I S1.4 1983 and ANSI S1.43 1997
3,Real time 1/1 and 1/3 Octave in accord ance with IEC 61260 1:2014 and ANSI S1.11 2004
4,Linearity r ange: 22dBA~136 dBA ( MEWOI-TW408A,TW408B ), 25 dBA~136dBA (MEWOI-TW409A,TW409B)
5,Single ran ge to cover 123dB ( MEWOI-TW408A,TW408B ) / 122dB (MEWOI-TW409A,TW409B) dynamic range
6,Frequency weighting : A/B/C/Z. Time weighting Fast/Slow/Impulse
7, 3 profile and 14 custom define measurement are calculate in parallel with different frequency/time weighting
8,Calculate SPL, LEQ, Max, Min, Peak, SD, SEL, E
9,LN statistic al and time history curve display
10,User define integral period measurement , integral period up to 24h
11,High speed ARM core with FPU (Float Point Unit) to achieve wide frequency response large dynamic range and low noise floor
12,4G MicroSD card (TF card) mass storage
13,RS 232 remote control port
14,Mini thermal printer for measurem ent data print
15,Internal GPS module ( optional), support GPS timing


1,Basic noise measurement
2,Environmental noise assessment
3,Product quality check
4,Evaluation of noise reduction engineering

The improvement of MEWOI-TW408A,TW408B,TW409A,TW409B

1,Single chip high speed ARM with FPU2,USB port function implement ed
3,White backlight LCD4,U pdate firmware via USB (also power supply)
5,Integral period from 1s~ 24h6,Timer feature support auto measurement
7,0.1s, 0.2s, 0.5s logger step added8,Internal GPS (optional) with GPS timing
9,5 templates to save user setting10,Single range to cover 123 dB dynamic range
11,B weighting added to meet ANSI standard12,Reduce the noise floor (only for Class 1)
13,Automatic power on with external supply ,ease of integration

14,Upper limit of measurement:136 dBrms /139 dBpeak (4 0mV/Pa)


MEWOI-TW408A(Class 1+1/1OCT)MEWOI-TW408B(Class 1+1/1OCT+1/3OCT)MEWOI-TW409A(Class 2+1/1OCT)MEWOI-TW409B(Class 2+1/1OCT+1/3OCT)
AccuracyClass 1Class 1Class 2Class 2

Real time 1/1 Octave: 8Hz-16kHz

Real time 1/3 Octave(Optional)6.3Hz 20 kHz

GBT3241-2010 , IEC 61260-1:2014

ANSI S1.11-2004 . Base 10 system

Real time 1/1 Octave: 20Hz-8kHz

Real time 1/3 Octave(Optional) 20Hz-12.5kHz

GBT3241-2010 , IEC 61260-1:2014

ANSI S1.11-2004 . Base 10 system



MPA231T: 1/2 pre polarized measurement microphone, Class 1. Sensitivity: 4 0mV/Pa.

Frequency Range: 3 Hz~ 20kHz.

MPA309 T : 1/2 ” pre polarized measurement microphone, Class 2 . Sensitivity: 4 0mV/Pa.

Frequency Range: 2 0Hz~ 12.5 kHz.

Mic Interface

TNC connecter with ICCP power supply ( 4mA

Detector / Filter

Fully float point digital signal processing (digital detector and filter

Integral PeriodInfinite or 1s 24h user define integra l period. Repeat time: I nfinite or 1~9999
Logger Step

0.1s , 0.2s , 0.5s , 1s~24h



LXY(SPL) SPL), L Xeq , L XY SD , L X SEL , L X E , L XYmax , L XYmin , L XPeak , L XN . Whe re X is the frequency weighting: A,

B, C, Z; Y is time weighting: F, S, I; N is the statistical percentage 1 99 3 profile and 14 custom

define measurement are calculat e in parallel with different frequency/time weighting

24h Measurement

Automatic measurement based on user define date/time and save the history data

Frequency Weighting

Parallel A , B , C , Z It can also be applied to 1/1 and 1/3 Octave

Time Weighting

Parallel F , S , I and Peak detection

Self Noise

Sound: 19dB(A), 25dB(C),31dB(Z)

Electrical:13dB(A), 17dB(C), 24dB(Z)

Sound:20dB(A), 26dB(C), 31dB(Z)

Electrical:14 dB(A), 19 dB(C), 24dB(Z)

Upper Limit

136dB(A), Increase to 154dB(A) with 5mV/Pa Microphone





Level Linearity


22dB(A)-136dB A,Octave: 30dB-136dB

25dB(A)~136dB(A),Octave: 33dB-136dB

Dynamic Range

123dB(13dB (A)~136dB(A))

122dB (14dB(A)~136dBA)
Peak C Range47dB-139dB50dB~139dB
Electrical I nput

Maximum input voltage: 5Vrms 7.07Vpeak ). Input impedance of preamplifier : >6 G Ω

Range Setting

Single range to cover whole dynamic range



Sampling Rate48kHz
Time HistoryTime domain noise curve display. Duration time: 1min , 2min , 10min
LCD Display

160x160LCD with white backlight, 14 step contrast level , 1s display update rate

Mass Storage

4G MicroSD card ( TF card)

Post Processing

Post processing software VA SLM ca n read , analy ze and generate reports of store data

Export DataDirectly connect to the c omputer to read the memory card (USB disk)

AC Output max 5V RMS , 15mA ), DC Output (10mV/dB , max 15mA, RS232 serial interface and USB (USB disk mode or modem


User define alarm threshold. LED indicate the alarm status

Setup Template

5 templates to save user setup for different application, template can be save in MicroSD card

Auto Power On

Automatic power on and start measurement when power supply available , ease of integration

Power Supply

4x1.5V alkaline batteries (LR6/AA/AM3), sustainable use of approx. 1 0 hours depend s on battery). It also can be supply by external DC power ( 14V 500mA) and USB po wer (5V 1A)


Builtin backup battery has been calibr ated at factory to the error<26s in 30days (<10ppm, (25±16) ºC). It can keep RTC running when replacing the main batteries

GPS timing function,available (optional with GPS)


English, Chinese,Portuguese , Spanish , German, French

Firmware UpdateUpdate firmware via USB port

Temperature: 10º C 5 0º C. Humidity : 20 9 0 %RH

RT Temperature

Realtime tempera ture display on the main screen

Size (mm)W70 x H300 x D36

Approx. 620g , including 4 alkaline batteries


GPSReceiver Type: 50 Channels; Time To First Fix: Cold Start 27s , Warm Start 27s , Hot Start 1s

Sensitivity: Tracking-161dBm , Reacquisition-160dBm , Cold Start-147dBm , Hot Start-156dBm

Horizontal position accuracy: 2.5m , Timing accuracy: 30ns , Velocity accuracy: 0.1m/s

Update Rate: 1Hz , Operation Limits: Dynamic ≤4g , Altitude<50000m , Velocity <500m/s

CalibratorCA111, Class 1, 94dB/114dB, 1kHz

Mini thermal or dot-matrix printer, RS232 port


Note 1:Ignore the result outside 20Hz~ 12.5kHz for type MEWOI-TW409 alone due to microphone frequency response of Class 2.

Note 2: The data was measured with 40mV/Pa microphone for MEWOI-TW408 and TW409 Series.

Note 3: Measurement according to GB/T 3785 and IEC 61672.

Note 4: Measurement according to GB/T 3 241 and IEC 61260.

label:   Sound level meter Medidor de Nível de Pressão Sonora Digital SONÔMETRO Decibelímetro Digital

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