crobars of pressure). This reference can be found
segments.
'
on our sound chart. It
is
94dB spl, 10 microbars,
10
dynes per cm2 or
1
Newton per square meter.
For mics, the reference
"0"
is
1
volt (dB). So, if
the sound
is
94dB spl, the electrical output of
the rnic
is
given
as
-60dB, meaning so many dB
less than the reference 0=1 volt. In practice, you
will see
levels of -60dB for low level dynamics,
up to about
-40dB
or slightly higher for the
better grade of condenser mics available today.
TASCAM recorders and mixers work
at
a
level
of
-10dB referenced to 1 volt (0.3 volt) so, for
94dB spl,
a
rnic with
a
reference output of
-
60dB
will
need 50dB of amplification from your M-35
or recorder in order to see "OVU"
(-
l
OdB) on
your meter. Now, if the sound you want to re-
cord
is
louder than 94dB spl, the output from
/
the rnic will be more powerful and you will need
less amplification from your IVI-35 to make the
needles on your recorder
read "OVU".
THE
BLOCK
DIAGRAM AND GAIN
BLOCK
DI AG RAM
'
Before you begin reading the next section of this
manual, flip out the extra fold on page 42. On
this page, we
have printed the block diagram. It
shows the signal flow through the M-35 and
it
represents in simple form, the actual electron
arrangement of
al1
the jacks, controls and gain
stages from
mic-in to line-out.
The diagram on page 43 indicates the gain of
a
"
reference signal, the noise level, and the available
reserve gain or headroom
at
any point in the
signal chain. An experienced audio engineer
would be able to operate the M -35 successfully
with just these two diagrams and
a
list
of input
and output specifications.
Any question about function or gain
can be an-
swered by studying the drawings. Will the acces-
sory send signal change in level if the input fader
is
moved? No, the signal
is
shown leaving the
main line before the input fader. You read both
diqgrams from left to right, input to output.
1. As laid out for
convenience.
2. As wired, but knobs and jacks
as
they appear
on the outside.
3. The block diagram, with the controls
num-
bered
to correspond to numbers on the first
two drawings.
Even with this "translation system" to help, mul-
tiple sources and outputs
can complicate things,
so when necessary; we will
also include other
types of drawings to help get the point of
a
sub-
system across when we first encounter
a
source
"point" that will be used in
a
specific way. This
may
require re-reading if you are not familiar
with subsystems, but we think
it
best to advise
you
as
early
as
possible.
When printed in
its
entirety,
a
block diagram can
look formidable, and tracing
a
signal path
is
not
/
easy, so to aid you in your initial understanding,
we'll continue to use our 3 drawing system first
shown in the introduction, but in slightly smaller
d
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