Electret condenser microphone with low noise figure and method for producing the same

An electret condenser microphone, comprising a housing, an electret variable condenser, and an ASIC (application-specific integrated circuit) amplifier;

• the electret variable condenser and the ASIC amplifier being installed in the housing, the ASIC amplifier being mounted on a printed circuit board, an output terminal being disposed on the printed circuit board;
• the electret variable condenser being electrically connected to the ASIC amplifier, the ASIC amplifier being electrically connected to the output terminal on the printed circuit board;
• wherein the electret variable condenser includes a back plate, an annular insulating spacer, and a diaphragm assembly that can vibrate up and down, the back plate has an electret layer thereon;
• the housing has a mounting chamber with an opening at one end thereof, the diaphragm assembly, the annular insulating spacer and the back plate are all mounted in the mounting chamber from the opening, the printed circuit board is mounted in the mounting chamber and covers the opening;
• the annular insulating spacer is disposed between the diaphragm assembly and the back plate so that the diaphragm assembly and the back plate are separated to form a sound chamber for collecting sound;
• wherein the electret variable condenser further includes a holder mounted in the mounting chamber, the holder is disposed between the printed circuit board and the annular insulating spacer, the holder has a back plate mounting portion, the back plate is mounted to the back plate mounting portion, and the annular insulating spacer is press-fitted between the holder and the diaphragm assembly;
• and, wherein the back plate is provided with a first sound hole, the holder is provided with a second sound hole, the first sound hole is in communication with the second sound hole, and at least one of the first sound hole and the second sound hole is provided with a damping plate.