Technical information

space savings. It preserves the original signal perfectly, even through multiple
encoding/decoding cycles.
MMC Multimedia Card. A small, removable flash memory (i.e. non-volatile)
cartridge.
MM cartridge Moving Magnet cartridge. See Moving magnet cartridge.
Mono or Monophonic. Where just a single channel carries all the sound. Even if
played back on a system with two or more speakers, the sound remains mono
because the left and right front speakers are delivering identical signals. Contrast
with stereo and surround sound.
Moving coil cartridge A magnetic cartridge in which the stylus moves a coil via
the cantilever, while the magnet is fixed in position. Moving coil cartridges tend to
have lower moving mass than moving magnet cartridges, but also tend to be
lower in output by an order of magnitude. There are, however, high output MC
cartridges available that produce comparable levels to MM cartridges. Because
the coil must be wired to the outputs, they also tend to be somewhat lower in
compliance than MM cartridges, so are not normally amenable to very low
tracking weights (they typically operate best at around two grams). The sound
qualities are generally thought to be better than any other cartridge type.
Moving magnet cartridge A magnetic cartridge in which the stylus moves a
magnet via the cantilever, while the coil is fixed in position. Moving magnet
cartridges tend to have a higher output than moving coil cartridges, but also tend
to have a higher moving mass (possibly reducing their ability to deliver fine detail
from record). Because the magnet is able to freely move, MM cartridges
generally offer a higher compliance than MC cartridges, so the cartridges with the
very lowest tracking weights (0.75 to 1 gram) come from the MM camp.
MP3 MPEG 1 Layer 3. This is a digital audio compression standard that achieves
high levels of compression of mono or stereo sound through perceptual encoding
techniques. MP3 encoded music listened to through a decent Hi-Fi system will
quickly show that, whilst claims are made as to ‘close to CD quality sound at the
highest encoding rate’ the removal of music data does reduce the quality. Good
for Internet music transportation and small portable solid-state players. MP3
supports bit rates of 8 to 320 kb/s.
MPEG Motion Picture Experts Group. In practice, this stands for a number of
audio and video compression standards. The video on DVDs is compressed
according to the MPEG-2 standard, which permits not only compression of each
single frame of the picture, but higher levels of compression by comparing frames
with each other and only encoding their differences. MPEG audio also appears on