To Adjust The Balance Control After The System Has Been Balanced; Adjusting For Special Effects; Using The C20 With A Stereo Tuner; Using The C20 With A Stereo Tape Machine - McIntosh C20 Owner's Manual

3. Set the HF CUTOFF FILTER to FLAT.
4. Set the LOUDNESS control to FLAT.
5. Rotate the INPUT SELECTOR to PHONO 1S or
PHONO 2S whichever is connected
you wish to hear.
6. Set the RECORD COMPENSATOR controls to
RIAA.
7. Set the BASS and TREBLE controls to 0.
8. Place the RUMBLE FILTER pushbutton in the
out position.
9. Place the TAPE COMPARE pushbutton in the out
position.
10. Rotate the VOLUME (OFF-on) control to on and
adjust to the desired volume.
TO ADJUST THE BALANCE CONTROL AFTER
THE SYSTEM HAS BEEN BALANCED
The balance setting of some records will differ
from others. If the sound is louder on the left than on
the right, adjust the BALANCE control to.the right to
bring the sound into "left-to-right" balance.
sound is louder on the right, adjust the BALANCE
control to the left.
If after balancing your stereo system, you find that
nearly all records require an adjustment of the BAL-
ANCE control, an unbalanced stereo cartridge is
probably the source of this condition. This is no great
disadvantage as it can be corrected by offsetting one of
the power amplifier input gain settings. When switching
from STEREO to REV, you will hear a change in volume
as a result of this correction.

ADJUSTING FOR SPECIAL EFFECTS

HF CUTOFF FILTER. If you wish to reproduce old,
badly worn records, you can minimize the surface noise
by switching the HF CUTOFF FILTER to 9KC or 5KC.
(See section entitled "Front Panel Facilities.")
RUMBLE FILTER. If you are using a turntable or
changer which has low-frequency rumble noise, you
may reduce it by pushing the RUMBLE FILTER push-
button to the IN position.
coupling in the very low-frequency bass range may also
be reduced in this manner.
BASS AND TREBLE. The tone balance which you
hear when listening to an orchestra is affected by the
conductor's instructions to his musicians, the acousti-
cal environment in which you are listening, and your
own subjective hearing interpretation. Even tone bal-
ance will vary within the room or hall where you listen
to the music. Considering these conditions, it is easy to
see why tone balance controls play a major role in
correcting the following factors:
1. Each person's subjective idea of tone balance.
2. Loudspeaker frequency response characteristics.
3. Loudspeaker placement in the listening room.
4. The conductor's idea of tone balance at the time
the recording was made.
to the cartridge
If the
Undesirable acoustic
5. The microphone frequency response character-
istics.
6. The recording process influences.
These factors can be considered as environmental
influences. The BASS and TREBLE controls are de-
signed to provide a degree of compensation for the
effects of environment. Listen to your system with each
control set at zero. If you wish to reduce treble in
relation to bass, rotate the TREBLE control counter-
clockwise until the tone balance sounds correct to you.
Do not be surprised if you find your preference in tone
changing from time to time. These controls will modify
tone balance without introducing any
effects.
Tone balance may be accented in the treble range
by rotating the TREBLE control clockwise. Similarly
tone balance in the bass range may be modified up or
down by use of the BASS control.
RECORD COMPENSATOR. The RECORD COM-
PENSATOR controls are used to correct for the neces-
sary program equalization which the recording process
introduces. Recording requires a change in the dis-
tribution of intensity with frequency. Without com-
pensation a magnetic cartridge would sound deficient
in the bass range and overly bright or shrill in the treble
range. Recommended settings of the RECORD COM-
PENSATOR controls of the C20 for monophonic records
are given in Table 3, page 12 .
LOUDNESS CONTROL. Due to a selective shift in
sensitivity of the human hearing, music reproduced
at very low volume loses its bass and treble. The family
of curves showing this effect are known as Fletcher-
Munson curves. (See Figure 13.) The LOUDNESS con-
trol on the C20 corrects for this effect. When you wish
to listen to music at a greatly reduced loudness level
and yet hear base and treble, turn the LOUDNESS
control to reduce intensity. Some users of the C20
leave the LOUDNESS control at positions 1 or 2 to
correct for environmental conditions such as loud-
speaker characteristics, room placement, etc.

USING THE C20 WITH A STEREO TUNER

A stereo tuner may be used with the C20 by plug-
ging the left and right channels into TUNER INPUT
1 or 2. When the INPUT SELECTOR switch is turned to
the TUNER positions, the record compensator pre-
amplifier is disconnected and the RECORD COMPEN-
SATOR controls will not require adjustment. The MODE
SELECTOR switch, BALANCE control, PHASE switch,
LOUDNESS control, BASS and TREBLE controls, the
RUMBLE FILTER, TAPE JACK switch, and VOLUME
(OFF-on) control all operate under this condition and
should be used in the same way as with any other
program.

USING THE C20 WITH A STEREO TAPE MACHINE

A stereo tape machine with its own playback pre-
amplifiers should be plugged into the TAPE INPUTS—
not the TAPE HEAD inputs. The information on adjust-
ing the C20 for listening to a stereo tuner will also
apply when listening to a tape machine.
undesirable
11