— 25 —
Demodulated
FM Audio
This metering area displays the demodulated FM program au-
dio.
Left
and
Right
channel levels have quasi-peak response and
a quick fallback for better visualization of instantaneous vs. av-
erage program energy. Keep in mind that these meters in no
way approximate “VU” ballistics. A floating peak-hold ‘ghost’
hovers briefly above these meters showing the highest peak
value recently indicated. This held value is shown numerically
at the right of the meters as well.
Sep
is a measure of stereo separation, based entirely on the lev-
el difference between the
Left
and
Right
meter readings. This
measurement is valid for steady-state-tone separation tests
with only one channel driven. It is
not
an indication of separa-
tion with dynamic (speech and music) program audio.
The
L+R
stereo sum and
L–R
stereo difference levels have the
same ballistic characteristics and scaling as the
Left
and
Right
meters above them. This dynamic sum-and-difference metering
gives a better visual representation of stereo separation with
program audio. Note that in the example above,
Left
and
Righ
t
levels are less than a dB apart, yet the
L+R
and
L-R
meters indi-
cate reasonable stereo activity. The fact that
Left
and
Right
me-
ters do not factor-in phase differences between the two chan-
nels explains this.
XTalk
(stereo crosstalk) is similar to the
Sep
(stereo separation)
measurement, but in this case it indicates the level difference
between the
L+R
and
L-R
program audio components. Like the
Sep
readout, it is useful only with tone tests and
not
an indica-
tion of crosstalk issues in the program audio.
FM Program
Loudness
The next subheading deals with the applicable Standard for
loudness measurement by the 551 Monitor. The bargraph
shown above is for FM loudness measurement, but typical of all
‘LU’ (Loudness Unit) readings.
Summary of Contents for Dante 551
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