Low-noise microphone

Abstract

Low-noise measuring microphone. Small measuring microphones have the disadvantage that their best equivalent noise levels still reach 24 dBA. In contrast, the solution according to the invention offers a ¼ inch measuring microphone with a substitute noise level of only 21dBA, even when using the smallest possible current of the standardized constant current supply, while maintaining this state throughout the entire modulation range, i.e. up to the maximum modulation.

Description

[0001] It is known that each microphone influences the sound field to be recorded more or less depending on its dimensions.

[0002] To minimize this influence, small microphones, for example with a diameter of ¼ inch or even less, are preferred, especially for measurement purposes.

[0003] To date, the best equivalent noise levels of approximately 24 dBA have been achieved using constant current powered ¼ inch measurement microphones.

[0004] Every condenser microphone requires a supply current for the internal circuitry, the level of which determines the microphone's controllability.

[0005] The object of the invention is to achieve an equivalent noise level significantly below 24 dBA, especially for ¼ inch measurement microphones, even with the smallest possible supply current of the standardized constant current supply and to ensure full functionality, in particular also the maximum control.

[0006] According to the invention, the solution consists in operating the microphone with a dual-diaphragm system from micromechanical manufacturing for sound recording, because each dual-diaphragm system improves the ratio of useful sound to background noise. The invention enables the construction of measurement microphones with a small diameter and low noise. This allows for an equivalent noise level of only 21 dBA using the smallest possible current of the standardized constant current supply, while maintaining this level across the entire control range, i.e., up to the maximum level.

[0007] The circuit structure of the measuring microphone is shown in the block diagram:

Claims

[1] Measuring microphone with constant current supply, characterized in that a double diaphragm system is used as the sound pickup. [2] Measuring microphone according to claim 1, characterized in that the double diaphragm system used is one made of micromechanical manufacture [3] Measuring microphone according to claim 2, characterized in that it is operated as a ¼ inch microphone with the smallest possible supply current of the standardized constant current supply. [4] Measuring microphone according to claim 2, characterized by an equivalent noise level of 21 dBA over the entire control range up to 130 dBA.

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