{"product_id":"gras-40bd","title":"40BD 1\/4\" Prepolarized Pressure Microphone","description":"\u003ch1 class=\"h3\"\u003e40BD 1\/4\" Prepolarized Pressure Microphone\u003c\/h1\u003e\n\u003cdiv class=\"p\"\u003e\n\u003cp\u003eThe 40BD is an IEC 61094 WS3P ¼″ prepolarized pressure microphone with rear-venting. It is a high-precision condenser microphone made according to IEC 61094-4 requirements. Its low sensitivity makes it ideal for sound measurements at high sound pressure levels of up to 174 dB. Its small size reduces the effects of diffraction and reflections around the microphone, resulting in a frequency range that extends up to 70 kHz.\nNOTE: Optimized for use without protection grid—remove grid before measuring.\u003c\/p\u003e\n\u003cp\u003e40BD is individually factory calibrated and delivered with a calibration chart stating its specific open-circuit sensitivity and pressure frequency response.\u003c\/p\u003e\n\u003cp\u003eNOTE: At low frequencies, protection grids are acoustically transparent; however, around 20 kHz and above, protection grids can act as resonators and influence the frequency response. So for higher frequency measurements, ¼ ″ and ⅛ ″ microphones have been optimized for use without the protection grid. Please remove the protection grid when measuring.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch2 class=\"h4\"\u003eKey Specifications\u003c\/h2\u003e\n\u003cdiv style=\"overflow-x:auto;\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003ePolarization\/Connection\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e0 V \/ CCP\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eFrequency range (±1 dB)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e10 Hz to 25 kHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eFrequency range (±2 dB)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e5 Hz to 70 kHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eDynamic range lower limit (microphone thermal noise)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e34 dB(A)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eDynamic range lower limit with GRAS preamplifier\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e44 dB(A)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eDynamic range upper limit with GRAS preamplifier @ +28 V \/ ±14 V power supply\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e166 dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eDynamic range upper limit with GRAS preamplifier @ +120 V \/ ±60 V power supply\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e174 dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eDynamic range upper limit with GRAS preamplifier\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e166 dB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eOpen-circuit sensitivity @ 250 Hz (±3 dB)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e1.6 mV\/Pa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eOpen-circuit sensitivity @ 250 Hz (±3 dB)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e-56 dB re 1V\/Pa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eResonance frequency\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e50 kHz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eMicrophone cartridge capacitance, typ.\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e7 pF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eMicrophone venting\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003eRear\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eTemperature range, operation\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e-40 to 120 °C \/ -40 to 248 °F\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eIEC 61094-4 Designation\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003eWS3P\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eTemperature range, storage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e-40 to 85 °C \/ -40 to 185 °F\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eTemperature coefficient @250 Hz\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e-0.01 dB\/°C \/ -0.006 dB\/°F\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eHumidity range  non condensing\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e0 to 100 % RH\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eStatic pressure coefficient @250 Hz\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e-0.008 dB\/kPa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eHumidity coefficient @250 Hz\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e-0.001 dB\/% RH\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eInfluence of axial vibration @1 m\/s²\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e55 dB re 20 µPa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e\u003cstrong\u003eWeight\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"border:1px solid #ddd;padding:6px;\"\u003e1.5 g \/ 0.053 oz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cem\u003eSpecifications from the official GRAS product sheet. Please refer to the attached datasheet for full details.\u003c\/em\u003e\u003c\/p\u003e","brand":"GRAS","offers":[{"title":"Default Title","offer_id":54036769472806,"sku":"40BD","price":0.0,"currency_code":"HKD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0953\/9797\/0214\/files\/40bd_web-1095x555.jpg?v=1791344425","url":"https:\/\/nplab.shop\/products\/gras-40bd","provider":"NP LAB","version":"1.0","type":"link"}