Kenwood DM-9090 instruction manual MD system

MD system

The Mini Disc system has the features as summarized in the following.

1Like CD (Compact Disc), playback can be started from any position. (Random access)

2 It uses a disc with a diameter of 64 mm that is accommodated in a cartridge.

3 Two types of discs can be used. (playback only discs, recordable / playable discs).

4 Up to 74 minutes of recording or playback is possible using high-efficiency coding technology. 5 Countermeasure against vibration is taken using semiconductor memory chip.

DM-9090 (En)

9

Playback-only Mini Disc

This type of MD can be used only for playback, and is used by the commercially-available mu- sic MD software packages. The playback-only MD is an optical disc like the Compact Disc (CD). The signals are recorded as the presence or absence of small pits and read out by an optical, non-contact pickup.

Recordable Mini Disc

This MD is a magneto-optical disc which can be recorded by magnetic field modulation. To record signals, laser light is irradiated from the bottom side of the magneto-optical disc and magnetic field is applied from the upper side of it.

Sound-skip prevention memory

During playback, this unit always stores signals in memory temporarily to prevent sound from being skipped in case of vibration. As a result, even when the data from the optical pickup is interrupted due to vibration, etc., the music will not be interrupted because the memory holds the data for several seconds.

During normal	Mini Disc
playback
	Several sec. of data
	Digital memory

The sound data for several	In case of vibration
seconds is always stored
during playback.

Reproduced sound

When the readout from disc is interrupted momentarily due to vibration or shock, the reproduced sound from the memory will not be interrupted.

Reproduced sound

High-efficiency coding technology “ATRAC” (Adaptive TRansform Acoustic Coding)

The Mini Disc has only a half the size of the Compact Disc but provides the same recording time. This is made possible by ATRAC*, a newly developed high-efficiency coding technology.

The ATRAC compresses the music data to about 1/5 the amount of data which would be obtained with conventional technology, by cutting off the sound components which do not pose problem in audition even when they are not present. This has made it possible to record or play up to 74 minutes.

Sound does not af- fect the sensitivity of ears

Sensitivity of ears

Lowest and highest frequencies are not audible unless the sound has a certain level of volume.

Lowest frequencies Highest frequencies

Small sound near large sound

A small sound is not audible to human ears if it is produced at the same time as a large sound. (Masking effect)

12

9 3 6

Monaural recording

This unit can record a longer period of sound in monaural (monaural long-play mode). In this mode, the recording time of the disc is about double that

in the stereo mode.
The Mini Disc recorded in the monaural mode cannot be played with equipment which is not compatible with monaural playback.	^

D.R.I.V.E. (Dynamic Resolution Intensive Vector Enhancement) system

This unit incorporates the KENWOOD-original “20-bit REC D.R.I.V.E.” system so that, not to mention the CD, analog sources such as the tuner and analog disk turntable can also be recorded with high-quality 20-bit recording.

The digital inputs include both optical and coaxial input jacks so that high-quality recording is possible from any digital equipment.

1The reproducibility of small signals is improved drastically for an excellent reproduction of fine reverberations of music. The excellence is also remarkable in the feeling of stability, presence, attack sound and bass reproduction.

2The D.R.I.V.E. system maintains the correlation between the musical components of the input and output signals and does not cause any sound degradation from the principle.

MONITOR function

This unit can be used as a 24-bit D/A converter by setting the MONITOR key. Refer to “MONITOR key”. £