G.R.A.S. 40LS 1/4" CCP Precision Surface Microphone

Freq range: 5 Hz to 70 kHz
Dyn range: 46 dB(A) to 167 dB
Sensitivity: 1.8 mV/Pa
  • 40LS 1/4

Typical applications and use

  • Automotive industry
  • Wind-induced noise measurement on vehicles
  • Outdoor measurements on testing grounds
  • Wind-tunnel testing


Just 2.5 mm thick, the 40LS has an integrated CCP preamplifier and is delivered with a built-in TEDS chip, which enables it to be programmed as a complete unit.

The 40LS requires a constant-current power supply, such as the G.R.A.S. 12AL CCP Supply, or any other CCP compatible power supply.

Close manufacturing tolerances together with the advantages of the TEDS chip, provide the 40LS with a high degree of interchangeability; a major advantage which excludes accounting for individual characteristics.

The 40LS is both very stable and robust. It has an integrated 1.5 m co-axial cable with a microdot connector and is delivered with a supple detachable silicon-rubber fairing.

Because of its lightness, the microphone with fairing can readily be mounted on surfaces using double-sided adhesive tape.

All G.R.A.S. microphones are individually checked and calibrated before leaving the factory.

An individual calibration chart is supplied with each microphone.

Frequency range (±1 dB) Hz 10 to 20 k
Frequency range (±3 dB) Hz 5 to 70 k
Dynamic range lower limit (microphone thermal noise) dB(A) < 46
Dynamic range upper limit with G.R.A.S. CCP preamplifier dB 167
Set sensitivity @ 250 Hz (±2 dB) mV/Pa 1.8
Polarization voltage V 0
Power supply (Constant Current Power) mA 2 to 20
Microphone venting Front
Output impedance Ω <50
Temperature range, operation °C / °F –55 to 100 / -67 to 212
Temperature range, storage °C / °F -40 to 85 / -40 to 185
TEDS UTID (IEEE 1451.4) 27 v. 1.0
Connector type Microdot 10/32
CE/RoHS compliant/WEEE registered Yes / Yes / Yes
Weight g / oz 3 / 0.101

Typical frequency response


G.R.A.S. GR0933 Adhesive tape, pre-cut, single-sided
G.R.A.S. GR0934 Adhesive tape, pre-cut, double-sided
G.R.A.S. MI0031 Cleaning tissue
G.R.A.S. AE0046 Adapter, BNC male to Microdot female
G.R.A.S. GR1252 Silicon-rubber fairing


G.R.A.S. 12AQ Power Module (2-ch.)
G.R.A.S. RA0202 Calibration Adapter (required)
G.R.A.S. 42AP Intelligent Pistonphone with built-inprecision barometer (250 Hz or 251.2 Hz,114 dB ±0.05 dB) (recommended)
G.R.A.S. 42AA Pistonphone (250 Hz, 114 dB ±0.08 dB)
G.R.A.S. GR1297 Stainless-steel fairing