DOLBY B AND C NOISE REDUCTION SYSTEM
• The Dolby noise reduction system substantially reduces the tape background noise (hiss)
inherent in the cassette medium. Dolby B NR is most widely in use. However Dolby C NR
is a much more recent development and represents significant improvements over Dolby
B NR.
• Tape background noise consists primarily of high frequency information, which is
particularly annoying during soft passages. The Dolby NR system increases the level of
low volume mid- and high-frequency signals during recording and reduces the level of
these signals by an identical amount during playback. As a result, the playback signal is
identical to the original source, but the level of background noise generated by the tape is
greatly reduced.
DOLBY HX-PRO HEADROOM EXTENSION SYSTEM
This deck is equipped with the Dolby HX-PRO headroom extension system. Since the system
functions automatically during recording, no switching operation or adjustment is required.
The system is effective with any type of Normal, Cr02 and Metal tape.
The Dolby HX-PRO headroom extension system functions during recording to raise the
saturation level in the treble range. Therefore, most of the treble range components distorted
or lost during recording on conventional cassette decks are more faithfully recorded on the
new DENON cassette deck.
MAINTENANCE
•
Head Cleaning
After long usage, tape coating or dust may adhere to the heads, causing deterioration
of sound. Therefore, the parts depicted in the illustration should be cleaned regularly.
Use a cotton swab moistened with a tape head cleaning solution (such as alcohol).
Note:
1. Some cleaning cassettes on the market have strong abrasive effects and may scratch
the heads. Always use cotton swabs instead of cleaning cassettes.
2. Since the use of metal tape is apt to collect more dust on the heads, the heads should
be cleaned more often to enjoy the best possible sound.
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• The operating principle of Dolby C NR is similar to that of Dolby B NR except for the
encoding /decoding response curves. The noise reduction effect obtained with Dolby C
NR is up to 20 dB, compared to 10 dB with Dolby B NR. In addition, Dolby C NR uses an
anti-saturation network and spectral skewing circuitry for a significant improvement in
the dynamic range of the mid- to high-frequencies.
Features of the Dolby HX-PRO Headroom Extension System
(1) Performance of Normal and Cr02 tapes can be improved to very close of that offered by
Metal tape.
(2) The dynamics in the treble range are improved significantly.
(3) Since no decoding is necessary during playback, the improved sound can be enjoyed on
any type of tape deck, including portable players and car audio systems.
(4) The system functions whether the Dolby B/C NR system is engaged or not.
•
Cleaning the Pinch Rollers and Capstans
If the pinch rollers or capstans accumulate dust, tape transport may become unstable,
as a result from slippage, during recording or playback. The tape can also be damaged
if it gets entangled in the capstan.
Clean these parts with a cotton swab or a soft cloth moistened with a tape head
cleaning solution (such as alcohol).
•
Demagnetizing the Heads
The heads will become magnetized after long usage or if strongly magnetized objects
are brought near them. The result is a generation of noise, loss of the high frequency
range, and in extreme cases erasure of treble components on pre-recorded tapes in
combination with added noise.
Thus, the heads should be demagnetized at regular intervals. (Head demagnetizers are
separately available from your dealer.)
•
How to Demagnetize the Tape Heads
1. Turn
off
the power.
2. Turn on the demagnetizer while it is at least 30 cm away from the heads. Bring the
demagnetizer near the heads and slowly move it in small circles four or five times in
front of each head, making sure you do not touch them.
3. Slowly move the demagnetizer away and turn it off when it is at
least 30 cm away from the heads.
