ScarletSound ST-109 Class 1 Sound Level Meter

ST-109 is a  Class 1 Sound Level Meter that meet the standard requirements of IEC 61672-1:2002 (or the equivalent BS EN 61672-1:2003). ST-109 Sound Level Meters are suitable for a wide range of applications including environmental noise measurements and occupational noise measurements for commercial, residential, industrial and noise sensitive environments deployment.


  • Fast, slow, Impulse response tmes.
  • Wide frequency range: 10Hz~20KHz.
  • Wide measurement range: 30dB~130dB
  • Wide dynamic range: 100 dB
  • A / C / Z frequency weighting
  • Sound Exposure Level SEL, Peak, Reverberation Time (RT60)
  • Data logger function, stored up to 32,000 records,auto-mating
  • Remote control through connected PC


  • Evaluation of environmental noise
  • Measurements of noise at workplaces
  • Design of cost-effective noise control plans
  • Assessment of product noise

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Item Description
USB interface Yes
Micro SD card Up to 32G
Bargraph display Yes
Display 3 1/2 digit backlit LCD display, maximum reading of 2000
Display refresh rate 1 time/ per second
Applicable specifications IEC 61672-1 : 2002 Class1, ANSI S1.4 Type 1, CNS NO.7129 Type 1, JJG-188-2002 Class1
Microphone 1/2″ pre-polarized condenser microphone build in preamplifier: -26 +/- 2dB (50mV/Pa), Fequency range: 10 Hz~20 kHz, heat noise : <28 dN(A)
Measurement items SPL, Leq, SEL,Max, Min
Measurement range 30dB ~ 130dB (A), 35dB ~ 130dB (C), 40dB ~ 130dB (Z)
Dynamic Range 100 dB
Integrate Time Setup randomly,10s, 1m, 5m, 10m, 30m, 1h, 2h, 4h, 8h, 16h, 24h or set in a given range
Max. peak C sound level measurement 70~133 dB
Time weighting Fast, Slow, Impulse, Peak
Frequency weighting A/C/Z
Frequency Range 10Hz~20KHz
DC output 2Vdc/130dB
AC output 2Vrms/130dB
Battery Life ~30 hours
Battery LR6 1.5V*4 Alkaline batteries
Dimensions 285(L) x 90(W) x 39(H) mm
Weight 550g (including Batteries); 2.5Kg (including package)



Weight 2.5 kg
Dimensions 285 × 90 × 39 cm

This instrument is guaranteed for one year against material or production defects, in accordance with Scarlet general sales conditions. During the warranty period the manufacturer reserves the right to decide either to repair or replace the product.

Should you need for any reason to return back the instrument for repair or replacement take prior agreements with the local distributor from whom you bought it. Do not forget to enclose a report describing the reasons for returning (detected fault). Use only original packaging. Any damage occurred in transit due to non-original packaging will be charged anyhow to the customer.

The warranty doesn’t apply to:

a) Accessories and batteries (not covered by warranty)
b) Repairs made necessary by improper use (including adaptation to particular applications not foreseen in the instructions manual) or improper combination with incompatible accessories or equipment.
c) Repairs made necessary by improper shipping material causing damages in transit. Repairs made necessary by previous attempts for repair carried out by non-skilled or unauthorized personnel.
d) Instruments for whatever reason modified by the customer himself without explicit authorization of our Technical Dept.

Shouldn’t the instrument work properly, before contacting your distributor make sure that batteries are correctly installed and working, check the test leads and replace them if necessary.

Scarlet products are patented. The logotypes are registered. The manufacturer reserve the right to modify characteristics and prices as part of technological developments which might require them.


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