High Temperature Surface Mount Pressure Mic for Accurate Placement in Confined Spaces
Microphone developed to withstand the harsh wheelhouse environment during brake testing
The GRAS 147EB-1 is an extra-rugged free-field CCLD microphone set, optimised for wheelhouse automotive brake noise testing. The rugged design and extra protection of the diaphragm make the GRAS 147EB-1 ideal for prolonged driving tests at proving grounds and on public roads. It provides accurate data under the most challenging conditions and can resist shock, vibration, water, dust and extreme temperatures. It has a watertight BNC connector.
The microphone-preamplifier assembly is effectively sealed against moisture and is IP67 rated. Special protective water and oil repellent coating adds further protection and makes it easy to clean. The microphone diaphragm is protected by two grids, a 1/2″ grid inside a 1″ grid. Each grid has a comprehensive multi-layer filtering system that ensures good protection against high-velocity particles and prevents dirt and dust from polluting the microphone. The filter in the 1/2″ grid is acoustically transparent. The filter in the 1″ grid is the same filter as that in the 1/2″ grid supplemented by a layer of foam. A correction curve is supplied for the influence of the 1″ grid enabling accurate measurements across the full audible range.
can be compensated for with the transfer function that is included with the factory calibration. The calibration data and transfer function can be accessed online. Provided the filters are replaced at appropriate intervals this system ensures that the microphone will function properly even in very dirty conditions. The filter also protects the diaphragm against water splashes and oil mists.
The protective grids and protective layers are replaceable and should be replaced periodically. If diaphragm damage does occur, the diaphragm can be replaced at a fraction of the cost of a replacement microphone set.
