ETMC Technologies :: G.R.A.S. Sound & Vibration :: Pistonphone Type 42AP is a battery-operated, precision sound source for accurate and reliable calibration of measurement microphones, sound level meters and other sound measuring equipment. It has a built-in precision barometer and a thermometer. Via its display and RS-232 interface, the user can read the actual corrected sound pressure level, as well as the calibration temperature and ambient static pressure.

<H1>No Frames? No Problem!</H1> <p><br>Go to G.R.A.S. Sound & Vibration web site with <A HREF="http://www.gras.dk/00012/00057/00153/00244/">no-frames</A>.</p> <p>The G.R.A.S. Pistonphone Type 42AP is a battery-operated, precision sound source for accurate and reliable calibration of measurement microphones, sound level meters and other sound measuring equipment. <p>It has a built-in precision barometer and a thermometer. Via its display and RS-232 interface, the user can read the actual corrected sound pressure level, as well as the calibration temperature and ambient static pressure. <p>With a microphone placed in the coupler of the pistonphone, the calibration level and frequency is: <p> * nominally 114dB re. 20µPa at either 250Hz or 251.2Hz <p>The actual sound pressure level, corrected for static ambient pressure, is shown on the display of the Pistonphone. The display can also show the A-weighted sound pressure level after correcting it for using an A-weighting filter. <p>An individual calibration chart is delivered with each Pistonphone. <p>The Display can be switched to show any of the following: <p> * Actual corrected sound pressure level in decibels <p> * Actual corrected sound pressure level in decibels if measured with an A-weighting filter <p> * Static air pressure in hPa <p> * Calibration temperature in ºC <p> * Calibration temperature in in ºF <p>The frequency of the pistonphone can be programmed, via its RS-232 interface, to be either 250Hz or 251.2Hz. <p>The Type 42AP is an extremely stable laboratory standard sound source which can also be used for field calibrations - it retains its high accuracy even under hostile environmental conditions. <p>The Type 42AP complies with all the requirements of IEC Standard 60942 (2003) LS. <p>Available accessories: <p> * RA0023 Adapter for 1" microphones <p> * RA0024 Two-port calibration coupler for ½" microphones. Used in comparison calibrations between two ½" microphones; one of which is a reference microphone. It can also be used in measuring the P-I (Pressure-Intensity) Index of intensity probes at 250Hz. <p> * RA0043 Adapter for G.R.A.S. Hydrophone Type 10CT / Reson TC4013 <p> * RA0046 (to be used with Adapter RA0055) Adapter for G.R.A.S. Hydrophone Type 10CC / Reson TC4032 <p> * RA0078 Adapter for G.R.A.S. Hydrophone Type 10CD / Reson 4033 <p> * RA0072 Octopus couplers for calibrating up to eight ½" microphones simultaneously. The main coupler of an octopus coupler, which replaces the pistonphone’s normal coupler, is connected to eight separate couplers via narrow-bore flexible tubes 50 cm long. Each of these separate couplers can accept a microphone or a plug substitute. <p><p>Specifications Type 42AP <p>Sound pressure level: 114 dB (re. 20 µPa) ± 0.05 dB <p>Frequency: 250 Hz and 251.2 Hz <p>Temperature range: - 10 °C to + 55 °C <p>Batteries: 4 × AA alkaline (IEC LR 6) <p>External power: 6V DC 125mA <p>Accuracy: IEC 60942 (ed.3/DIS) LS <p>Weight: 437 g