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Anleitung Zusammenfassung
Another primary application is as a table mounted microphone for picking up conversations from all directions, with none of the reflections, and consequent comb filtering, that plague microphones mounted on desk stands. In its role as a “half space” mounted microphone, its sensitivity is 6 dB greater than if it were placed in free space. Its balance between mid-frequency and low-frequency response is directly related to the boundary perimeter. If it is used on a temporary boundary, that boundary should have a perimeter of 20 feet (6 meters) if smooth response is to be ensured down to the lowest frequencies. The extremely small diameter of the entrance to the electret transducer ensures that the difference between on-axis and off-axis frequency balance will be virtually zero. That is, sounds arriving from all angles will maintain their spectral integrity. Since the microphone normally operates in the transition region between direct and reverberant fields, a random incidence “correction” has been incorporated into the microphone's response. This consists of a smoothly rising response above 3 kHz that reaches an average level of +6 dB over the range from 5 to 15 kHz. This provides a subjective improvement in overall musical balance. In the recording studio, boundary layer microphones provide a handy solution to problems of micing the piano. They may be positioned in pairs on the underside of the cover, with the cover up or down, for surprisingly good stereo pickup. Specifications Transducer Principle: Pre-polarized condenser Frequency Range: 20–20,000 Hz Polar Pattern: Hemispherically omnidirectional Sensitivity at 1,00 Hz: 20 mV/Pa -34 dBV measured on a boundary at least 1.5 m by 1.5 m Equivalent Noise Level: 16 dB-A Sound Pressure Level for 1% THD: 130 dB S/N Ratio (A-weighted): 78 dB Electr. Impedance: < 600 ohms Load Impedance: > 2,000 ohms Power Requirement: Phantom powering, 9–52 volts Connector: 3-pin XLR type Cable Length: 10 ft. (3 m) Finish: Dark gray Size: 6.3 in. (160 mm) diameter; thickness of plate 0.35 in. (9 mm) Net/Shipping Weight: 2.1 lbs. (0.95 kg)/4.2 lbs. (1.9 kg) Included Accessories: Foam-type windscreen Features • Flat profile for accurate boundary mounting • Extended low and high frequency response • Uniform hemispherical response • High sensitivity (20 mV/Pa) • High acoustic level capability (130 dB-SPL for 1.0% THD) Architects and Engineers Specifications The microphone shall be of the boundary layer type suitable for temporary or permanent mounting on flat surfaces. The microphone shall have a flat circular profile, with the condenser element mounted in the middle. The transducing element shall communicate directly to the outside through small openings. The sensitivity of the microphone shall be at least 20 mV/Pa when mounted on a boundary 4.95 feet (1.5 meters) on a side, and the frequency range shall extend from 20 Hz to 20 kHz. The response shall exhibit an average rise of 6 dB in the range from 5 kHz to 15 kHz to compensate for losses normally encountered in the operation of boundary layer microphones in the transition region between direct and reverberant fields. The self noise level of the microphone shall be no greater than 16 dB, as measured w...