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energy envelope occurs.
This results
in the full
gain applied
to the sibilants and reduced
gain
to the vowels,
creating an
exaggerated sibilant sound.
Again,
experimentation
is
the
best
tool.
3.5.4
PRIOR TO OUTPUT AMPLIFIER
Here the limiter fulfills mainly the function of protection.
Most equipment which
is fed
from the low level signal pathos output
terminal
is
sensitive
to
amplitude overload; the power amp's peak-
to-peak headroom, the saturation point of recording
tape, the
modu-
lation allowed
in
a
transmitter, the amplitude handling capability
of film recording devices, etc.
If
one were
to
summarize the
ideal
operation
of a
well adjusted
limiter, one could say:
"It
should afford infallible protection against overload, while
maintaining the highest
level,
contribute
no apparent
degrada-
tion
to the
dynamic range which might subjectively affect
the
artistic value of the program,
and, at the
same time, maintain
the individual
quality of
all sounds, regardless of their
starting transients."^
3.6
STEREO OPERATION
When stereo
signals are
processed the balance
of the two audio
channels
is
important.
To
maintain
a
good balance between channel A
and
channel
B,
the Model 1178
is
simply switched into
the STEREO
mode.
Then
the audio signal
with the
larger peak-to-peak amplitude
will cause the same amount of gain reduction
in
both channels.
The tracking of the GR circuitry
is
factory calibrated
and does
not need further adjustment.
However,
it
is
important
to
balance
the signal levels
with the Input controls since these determine how
much signal
is
within
the threshold of limiting.
The Output level
controls are used for make-up gain setting.
IT,
Ref. M.T. Putnam,
Audio Engineering Society
paper. Spring, 1967.
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