The G.R.A.S. RA0018 is a 20 dB attenuator for inserting between a 1/2" prepolarized microphone and preamplifier. It will attenuate the output signal of the microphone by 20 dB in order to avoid overloading the preamplifier. The RA0018 is useful when measuring very high sound pressure levels using a preamplifier with limited dynamic range. The RA0018 will work properly only with prepolarized microphones. For externally polarized microphones, use the RA0016.
For precision measurements, the actual combination of microphone, attenuator and preamplifier should be calibrated with a precision calibrator like G.R.A.S. 42AA Pistonphone. The attenuation of the microphone signal is obtained by a capacitive voltage divider, and depends on both the microphone capacity and the preamplifier input impedance.
Quality & Warranty
G.R.A.S. accessories are made of stainless steel, alloys and high-quality composites. These items are covered by a 2 year warranty respecting their intended use.
On consumables like batteries, cables and windscreens we offer a 6 month warranty.