Magnet Boot - A rubber or plastic cover for the speaker magnet for protection or appearance, mostly the latter.

Magnetic Flux - The magnetic lines of force produced in the area around an electric current or magnet.

Magnetic Flux Density - Measured in units of Gauss. The measurement of magnetic flux inside the air gap in which the voice coil of a speaker operates.

Magnetic Structure - Refers to to magnet assembly of a loudspeaker. Comprised of the magnet, pole piece, back plate and top plate.

MECP - Mobile Electronics Certification Program.

Memory - The word most commonly used to refer to a system's ability to retain specific information (time, stations etc.)..

Micro (µ) - A prefix that means one millionth. For example, 1 µV equals 1/1,000,000 of a volt.

Microprocessor - A multiple semiconductor IC device programmed or dedicated to perform a variety of tasks.

Midbass - Refers to frequencies roughly between 100 and 300 Hertz .

Midrange - A speaker usually between three and eight inches in diameter designated to reproduce only the mid frequency range from approximately 300 to 5000 Hertz.

Milli (m) - A prefix that means one thousandth. For example, 1 mA equals 1/1,000 of an amp.

Mixer - An audio processing device used to add (combine or sum) multiple inputs into one or two outputs, complete with level controls on all inputs.

Mms (a Theile Small parameter ) - The total moving mass of the speaker including the small amount of air in front of and behind the cone.

Mono (sound) - Also called monaural. A sound recorded or reproduced in only one single channel.

Mono (amplifiers) - Also called monaural. An amplifier producing only one channel of output. Can refer to an amplifier with only one channel or a two channel amp operating in bridged mode. For low frequency amplification applications, it eliminates phase cancellation that can occur in stereo operation.

MOSFET - (Metal Oxide Semiconductor Field Effect Transistor) These transistors are controlled by voltage rather than current, like a bipolar transistor only with much higher switching speeds. They exert little heat generation, improving response time, linearity and efficiency in the power supply. Mosfet transistors are typically used in high power output amplifiers.

MOSFET Power Supply - A power supply that uses MOSFET transistors to convert DC to AC, offering better thermal stability and more accurate switching.

Motor Structure - The part of a speaker that converts the incoming electrical signals to mechanical/acoustic energy or sound. This includes the magnet, pole pieces and the voice coil that interacts with them.

Mounting Depth - The amount of physical space required to mount a Driver without having any of its parts touch objects below.

Mounting Ring - A separate ring placed between a Driver and the surface on which it is mounted, for the effect of raising the speaker, reducing it's mounting depth.

Ms - The total moving mass of the loudspeaker cone.

MP3 (mp3) - The file extension for MPEG, audio layer 3. Layer 3 is a coding scheme for the compression of audio signals. It removes all superfluous information that the human ear doesn't hear. The result shrinks the original sound data from a CD by a factor of 12 without sacrificing sound quality. MP3 files can be encoded in varying amounts of compression. Lower compression rates will make the individual files smaller, so more can be stored in a given amount of drive space, but the sound quality will decrease. 128 kbps (kilobits per second) is considered OK sound quality, 192 kbps is high quality and 72 kbps is low fidelity.

Multimeter - A common term used to describe a VOM (voltage ohm meter). This device usually has the ability to measure volts, ohms, and amperes or milliamperes.

Mute - A control found on audio devices that drops the volume level dramatically or silences (mutes) an output.

Multi-tracking - The process of recording a multi-part performance on separate tracks at different times which allows the engineer to subsequently combine, balance and process those tracks during mixdown.