Using The Pushbuttons - McIntosh C34V Owner's Manual

expander or as a compressor. Expansion can restore
the dynamic range limited by the process of record-
ing both records and tape or broadcasting of music.
Compression decreases dynamic range. It can be
used for making tape recordings or for listening to
background music. The Compandor can be
switched to either the RECORD or LISTEN lines, by
means of the COMPANDOR pushbutton.
The Compandor System has four controls. The
concentric three-position COMPANDOR switch and
RATIO control are located on the front panel. The
LEVEL MATCH control and SPEED selector are lo-
cated on the C 34V top panel.
COMPANDOR SELECTOR
The outer COMPANDOR knob can be set to EX-
PAND, OFF, or COMPRESS. When the COMPAN-
DOR switch is in EXPAND or COMPRESS, a red
light will appear above the LISten-or RECord COM-
PANDOR pushbutton. In the center OFF position,
the Compandor System is switched out of the circuit
and the lights will be out. When the Compandor is
not used, the selector should be placed in the OFF
position.
RATIO CONTROL
The inner RATIO knob is used to control the
amount of expansion or compression.
LEVEL MATCH
The LEVEL MATCH control on the top panel is
used to adjust the listening level when the expander
or compressor is switched in or out of the circuit.
SPEED
The SPEED selector on the top panel is used to
control the rate at which the Compandor System re-
sponds to signals. By switching from FAST to NOR-
MAL to SLOW, a more gradual rate of change in ex-
pansion or compression occurs. For music with per-
cussive instruments, such as piano, drums, guitar,
etc., use NORMAL or FAST. In the FAST mode, the
Compandor System follows changes quickly but will
track low frequencies less accurately. Non-
percussive music and voice require slower speed.
At SLOW speed the low frequency tracking is ac-
curate, but the rate of response is slower. The NOR-
MAL position is best suited for most program
material.
USING THE COMPANDOR AS AN EXPANDER
When the COMPANDOR selector switch is in the
EXPAND position, the RATIO control is used to
select the amount of expansion. Full counterclock-
wise rotation corresponds to a ratio of 1.0. This
12 FRONT PANEL CONTROLS
means that the dynamic range of the expander out-
put is the same as the dynamic range of its input.
With the VOLUME control at a normal listening
level, the RATIO control is turned clockwise, the
output dynamic range becomes greater than the in-
put. Set the RATIO control to the desired expansion
(usually between 1.2 and 1.5). Now switch the
COMPANDOR selector knob between EXPAND and
OFF. A change in the average listening level will
usually be heard. Adjust the LEVEL MATCH (on the
top panel) control until the average listening levels
match as closely as possible when in EXPAND and
OFF. After this adjustment, you will notice that with
the expander on, loud passages will be louder and
soft passages will be softer tending to make any
background noise quieter.
When the RATIO control is at the fully clockwise
position, it corresponds to a ratio of 2.0. The output
dynamic range is then twice the input dynamic
range. This setting is extreme for most program
material.
USING THE COMPANDOR AS A COMPRESSOR
When the COMPANDOR selector switch is in the
COMPRESS position, the RATIO control is used to
select the reduction in dynamic range desired. Full
counterclockwise rotation corresponds to a ratio of
1.0. The compressor output and input dynamic
range will be the same. Set the VOLUME control to
a normal listening level. As the RATIO control is
turned clockwise, the output dynamic range be-
comes less than the input range. Set the RATIO
control to the desired amount of compression.
Switch the COMPANDOR selector knob between
COMPRESS and OFF. A change in the average lis-
tening level will usually be heard. Adjust the LEVEL
MATCH control until the average listening levels
match as closely as possible when switching be-
tween COMPRESS and OFF. After this adjustment,
you will notice that with COMPRESS on, loud
passages will be softer and soft passages will be
louder.
When the RATIO control is at the fully clockwise
position it corresponds to a ratio of 2.0. The output
dynamic range is then one half of the input range.
This setting can be useful to create highly compress-
ed tape recordings particularly useful in noisy loca-
tions such as automobiles, etc.
Two examples for using the expander are:
1. To reduce background noise (hum, hiss or
scratch):
a. Select the desired program source with the