Owner's Manual
Table Of Contents
1&21 Discrete 1&21 Sum
Tuning
Hint:
If
you are using the M4300
to drive a subwoofer system ("LP" mode), a
component satellite speaker system
("HP"
mode)
or both, 80 Hz
is
a good baseline "Filter Freq.
(Hz)" setting. After properly adjusting the
"Input
Sens.",
as
outlined in Appendix A (page
14),
you
can fine tune the "Filter Freq. (Hz)" control to
achieve the desired system frequency response.
2)
"Filter
Freq. (Hz)" The filter frequency
markings
surrounding
this rotary control
are for reference purposes
and
are generally
accurate to within 1/3 octave or better.
If
you
would like to select the filter cutofffrequency
with a higher level
of
precision, consult the
chart
in Appendix B (page
15).
1)
"Filter
Mode"
Control:
The M4300 employs a
12dB per octave filter for each pair
of
channels
(one filter for channels
1&2
and another filter
for channels 3&4). Each
of
these filters can
be configured independently into one
of
two
filter types or defeated completely by way
of
the
three-position "Filter Mode" switches:
"Off":
Defeats the filter completely, allowing
the full range
of
frequencies present at the
inputs to feed the amplifier. This
is
useful
for systems utilizing outboard crossovers
or
requiring full-range reproduction from one or
both
of
the M4300's channel pairs.
"LP"
(Low-Pass): Configures the filter to
attenuate frequencies above the selected filter
frequency at a rate
of
12dB per octave. This
is
useful for connection
of
subwoofer(s) to one
or
both
of
the M4300's channel pairs in a
bi-amplified system.
"HP"
(High-Pass): Configures the filter to
attenuate frequencies below the selected filter
frequency at a rate
of
12dB per octave. This
is
useful for connection
of
component speakers to
one or
both
of
the M4300's channel pairs in a
hi-amplified system.
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11
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2 Controls Filter Freq. (Hz)
Channel
3 & 4 Controls Filter Freq. (Hz)
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FILTER
CONTROLS
Most speakers are not designed to reproduce
the full range
of
frequencies audible by the
human
ear. For this reason, most speaker
systems are comprised
of
multiple speakers, each
dedicated to reproducing a specific frequency
range. Filters are used to select which frequency
range
is
sent to each section
of
a speaker system.
The division
of
frequency ranges to different
speakers can be done with passive filters (coils
and/or
capacitors between the amplifier outputs
and
the speakers), which are acceptable
and
commonly used for filtering between mid-
range speakers and tweeters. Filtering between
subwoofer systems
and
satellite speaker systems
is
best done with active filters, which cut off
frequency content at the input to the amplifier.
Active filters are more stable
than
passive filters
and do not introduce extraneous resistance,
which can degrade subwoofer performance.
The active filter built into each channel section
of
the M4300 can be used to eliminate potentially
harmful
and/or
undesired frequencies from
making their way through the amplifier sections
to
the speaker(s). This serves to improve tonal
balance and to avoid distortion and possible
speaker failure. Correct use
of
these filters can
substantially increase the longevity and fidelity
of
your audio system.
Do
not
increase
any
"Input
Sens."
setting
for
any channel(s)
of
any
amplifier
in
the
system
beyond
the
maximum
level established
during
the
procedure
outlined
in
Appendix
A (page
14).
Doing
so will result
in
audible
distortion
and
possible
speaker
damage.
..JL
AUDIO
M4300
7