BSWA308 Sound Level Meters

BSWA 308/BSWA 309 are octave sound level meters updating the dual-core (DSP+ARM) architecture to single chip ARM with float point unit, and updating all fix-point calculation to float-point, which signif cantly improves the accuracy and stability. Re-design analog front end circuit also lower the noise floor and linear range of product.

BSWA 308 is Class 1 and BSWA 309 is Class 2. Both instruments have certificated by the China CPA (Certification of Pattern Approval) and CMC (China Metrology Certification).

Single chip high speed ARM with FPU USB port function implemented
White backlight LCD Update firmware via USB (also power supply)
Integral period from 1s~24h Timer feature support auto measurement
0.1s, 0.2s, 0.5s logger step added Internal GPS (option) with GPS timing
5 templates to save user setting Single range to cover 123dB dynamic range
B-weighting added to meet ANSI standard Reduce the noise floor (only for Class 1)
Automatic power on with external supply, ease of integration Upper limit of measurement: 136dBrms/139dBpeak (40mV/Pa)

Product Features:

● Class 1 (BSWA 308) and Class 2 (BSWA 309) sound level meter

● Comply with IEC 61672-1:2013, ANSI S1.4-1983 and ANSI S1.43-1997

● 1/1 Octave in accordance with IEC61260-1:2014 and ANSI S1.11-2004

● Linearity range: 20dBA~134dBA (Class 1), 25dBA~136dBA (Class 2)

● Single range to cover 123dB/122dB dynamic range

● Frequency weighting A/B/C/Z. Time weighting Fast/Slow/Impulse

● 3 profile calculation in parallel with different frequency/time weighting. 14 custom define measurement

● Calculate SPL, LEQ, Max, Min, Peak, SD, SEL, E

● LN statistics and time history curve display

● User def ne integral period measurement, integral period up to 24h

● High speed ARM core with FPU (Float Point Unit) to achieve wide frequency response, large dynamic range and low noise floor

● 4G MicroSD card (TF card) mass storage

● RS-232 remote control port

● Mini thermal printer for measurement data print

● Internal GPS module (option), support GPS timing.

Technical Parameters:



BSWA 308


Class 1 / Group 1


GB/T 3785.1-2010,  IEC 60651:1979, IEC 60804:2000, IEC 61672-1:2013, ANSI S1.4-1983, ANSI S1.43-1997


1/1 Octave, Centre Frequencies: 31.5Hz to 16kHz GB/T 3241-2010 Class 1, IEC 61260-1:2014 Class 1 ANSI S1.11-2004 Class 1

Supplied Microphone

MPA231T: 1/2” prepolarized measurement microphone, Class 1. Sensitivity: 50mV/Pa. Frequency Range: 10Hz~20kHz.

Mic Interface

TNC connecter with ICCP power supply (4mA/24V)

Detector / Filter

Fully float-point digital signal processing (digital detector and filter

Integral Period

1s-24h user define integral period. Repeat time: infinite, 1~9999

Measurement Functions

LXY(SPL), LXeq, LXYSD, LXSEL, LXE, LXYmax, LXYmin, LXPeak, LXN. Where X is the frequency weighting: A, B, C, Z; Y is time weighting: F, S, I; N is the statistical percentage: 1~99.

24h Measurement

Automatic measurement and log the history data

Frequency Weighting

Parallel A, B, C, Z 

Time Weighting

Parallel F, S, I and Peak detection


Sound: 18dB(A), 23dB(C), 31dB(Z)   Electrical: 11dB(A), 16dB(C), 21dB(Z)

Upper Limit

134dB(A) Increase to 154dB(A) with 5mV/Pa Microphone

Frequency Response


Linearity Range


Dynamic Range

123dB (11dB(A)~134dB(A))

Peak C Range


Range Setting

Single range to cover whole dynamic range



Sampling Rate


Noise Curve

Time domain noise curve display. Duration time: 1min, 2min, 10min

LCD Display

160x160 LCD with white backlight, 14 step contrast level

Mass Storage

4G MicroSD card (TF card)


Post-processing software VA-SLM can read, analyze and generate reports of store data

Export Data

Directly connect to the computer to read the memory card (USB disk)


AC (max 5VRMS output), DC (10mV/dB), RS-232 serial interface and USB virtual serial port


User define alarm threshold. LED indicate the alarm status

Power Supply

4x1.5V alkaline batteries (LR6/AA/AM3), sustainable use of more than 10 hours. It also can be supply by external DC power (7V-14V 500mA) and USB power (5V 1A)


Built-in backup battery has been calibrated at factory to the error <26s in 30days (<10ppm, 25±16℃). It can keep RTC running when replacing the main batteries. GPS timing function available (option with GPS module)

Firmware Update

Update firmware via USB port


Temperature: -10℃~ 50℃. Humidity: 20% ~ 90%RH

RT Temperature

Real-time temperature display on the main screen

Size (mm)

W70 x H300 x D36


Approx. 620g, including 4 alkaline batteries


Receiver 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


CA111, Class 1, 94dB/114dB, 1kHz


Mini thermal printer, RS-232 port

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