The GRAS 46AE is a Class 1 1/2-inch free-field condenser measurement microphone from GRAS Sound & Vibration, used in environmental noise, sound power, NVH, and general-purpose acoustic measurement. PLACID Class 1 free-field measurement microphones (PM200 series) target the same application range. This comparison addresses the key specification and documentation differences to support instrument selection.
Both instruments are externally-polarised condenser capsules with standard 1/2-inch thread dimensions, IEC 61094-4 Class 1 compliance, and frequency response suitable for measurement to 20 kHz. Both are available with ISO/IEC 17025 accredited calibration from accredited laboratories.
For most environmental noise, sound power, and NVH measurement applications, both instruments are equally appropriate. The selection between them is typically based on preamplifier compatibility with existing infrastructure, calibration laboratory preference, and total cost of ownership. Contact PLACID to discuss your specific requirements and to request a compatibility assessment if you are evaluating PLACID capsules as replacements for existing GRAS 46AE installations.
One differentiated feature of the PLACID programme is the long-term stability monitoring service. PLACID reference microphone capsules are returned to the calibration laboratory on an annual basis and subjected to repeat sensitivity measurement. The resulting multi-year sensitivity history provides evidence that the calibration uncertainty budget is valid over the claimed calibration interval — important when a measurement programme is subject to regulatory scrutiny or third-party audit. This type of inter-calibration stability record is not typically provided as standard by other microphone manufacturers.