The AMT M40 is Applied Microphone Technologys legendary piano microphone system. Designed, manufactured by hand, and distributed by AMT in the USA. The system is intended to set inside the piano normally between the 2nd and 3rd sound holes on the cast iron plate of a grand and fastened to the front bottom door of an upright piano.The M40 achieves the most natural sound possible out of a microphone. Mono in design, the system can be used with a flat EQ setting allowing plenty of gain before feedback all while maintaining the pure and natural sound that each different piano has. Applied Microphone Technology designs microphone specific for each instrument and does not adapt one microphone for many instruments.The M40 is a bold new direction for microphones incorporating integrated circuit technology. The M40 has been designed for piano but works equally well in other applications such as boundary layer micing (conference, stage).The system allows the microphone to be used with the piano lid closed. Cumbersome microphone stands not needed, as the system is very compact with many possible placements. The M40 is the only system on the market that will allow a close-lid application successfully. It is capable of picking up subtle passages as well as sound pressure levels up to 141dB.The M40s rugged construction of anodized aviation aluminum allows it to withstand high impact while being lightweight and non-corrosive. The signal from the AP40 or AP41 preamp can be split with frequencies rolled off in a specific way to create a stereo image.The M40 terminates to the AP40 (Studio) aluminum pre-amp with chip technology, which can be powered by phantom power or 9 volt battery. Comes with hard shell case.The M40P terminates to the AP41 aluminum pre-amp which includes a transformer and a external power supply. (110 Power supply included)"