Genelec 7070A - Manual (Page 6)

The LFE channel on the 7060A, 7070A
and 7071A can be set to two frequency
ranges: 19 to 85 Hz or 19 to 120 Hz by
using the "LFE BANDWIDTH" switch. If the
LFE signal includes higher frequencies than
120 Hz, they can be monitored by using the
"Redirect" function: Set "LFE BANDWIDTH"
switch to "85" and the "REDIRECT" switch
to "ON". Now the subwoofer reproduces
LFE frequencies up to 85 Hz and reroutes
all higher LFE content to the front center
channel. This is the most fl exible setting
for LFE signal management, as it ensures
that all LFE content can be monitored in all
situations and encoding formats. Note that
the "Redirect" function is not enabled when
the "LFE BANDWIDTH" switch is set to 120
Hz.
Typical applications of different
LFE bandwidth settings
As stated above, using the 85 Hz LFE band-
width setting with "Redirect" function is the
most universal confi guration for LFE moni-
toring. However, there are situations when
the band-limited LFE settings serve a defi nite
purpose.
Limiting the LFE bandwidth to 85 Hz with-
out using the "Redirect" function can be
used to simulate the effect of some con-
sumer decoders that do not replay informa-
tion above 80 Hz on the LFE channel when
the bass management is used. Checking the
multichannel mix with this setting on lets you
know how it translates in systems with this
limitation.
The 120 Hz LFE bandwidth setting com-
plies with the replay systems of movie theat-
ers and cinemas. 35 mm movie soundtracks
use the LFE channel to reproduce a band-
width of 20 - 120 Hz through dedicated sub-
woofers. In this case the LFE and main chan-
nel bandwidths overlap between 85 and 120
Hz, which may create unwanted acoustical
summing if the same signal is present in
both channels. To avoid this, the LFE con-
tent should be kept completely different (de-
correlated) from the low frequency content of
the main channels when mixing music and
sound effects for fi lm release.
Using the LFE +10 dB function
In Dolby Digital and DTS encoding formats
the LFE channel has to be monitored with
+10 dB gain in relation to the main channels.
The object is to increase the recording head-
room of the LFE channel. Consumer and the-
atrical decoders automatically add +10 dB of
LFE gain to restore the level balance.
The "LFE +10 dB" function on the 7060A,
7070A and 7071A subwoofers is designed to
add the +10 dB gain to the LFE channel in
the production stage, if it is not already done
in the output matrix of the mixing console.
The function is activated by switching the
"LFE +10 dB" dip switch on the subwoofer's
fi rst switch group to "ON" or by using the
remote control. A yellow LED indicates that
the function has been activated.
The "LFE +10 dB" function should not be
used in following cases:
•
If the +10 dB LFE gain is already
implemented by another device.
•
When producing an audio format that
does not require the use of +10 dB
gain on the LFE channel, such as
DVD-Audio (MLP), SACD (DSD) etc.
•
When monitoring a decoded Dolby
Digital or DTS soundtrack. The decoder
will automatically provide +10 dB
LFE gain.
Using multiple subwoofers
Genelec 7060A, 7070A and 7071A subwoof-
ers are equipped with a "SUM OUT" connec-
tor to provide an easy way of coupling two or
more subwoofers together in high SPL appli-
cations. Table 2 shows the recommended
confi gurations with different Genelec moni-
tors. Connect an XLR cable from the "SUM
OUT" connector of the "master" subwoofer
to which the main monitor channels are con-
nected, to the "LFE IN / SUM IN" connector
of the other, "slave" subwoofer and turn the
"SUM IN MODE" dip switch on the "slave"
subwoofer to "ON".
When two subwoofers connected in this
way are positioned close to one another, bass
level increases by 6 dB. Three subwoofers
give an SPL increase of 9,5 dB and four
subwoofers 12 dB compared to a single
subwoofer. Adjust the sensitivity control of all
subwoofers in the group to match the SPL
level of the main monitor system.
Phase and Bass Roll-Off adjustments
should be done individually for each
subwoofer in the chain, especially if they
are not placed close together. To check the
phase alignment for the "master" subwoofer
switch off the "slave" subwoofer and follow the
instructions given in the previous sections.
To adjust the phase alignment of the
"slave" subwoofer, you need to switch off
the "master" subwoofer, connect a signal
cable from the "slave" subwoofer's "FRONT
CENTER OUT" connector to the center
channel monitor and switch the "SUM IN
MODE" switch to "OFF". This effectively
changes the "slave" to "master" mode and the
phase adjustment can be carried out. Return
the connections and "SUM IN MODE" setting
on the "slave" subwoofer back to the "SUM
IN" mode after completing the adjustment.
Safety considerations
The LSE series subwoofers have been
designed in accordance with international
safety standards. However, to ensure safe
operation and maintain the unit in safe oper-
ating condition, the following warnings and
cautions must be observed:
•
Do not expose the subwoofer to water
or moisture. Do not place any objects
fi lled with liquid, such as vases on
the subwoofer or near it.
•
Servicing and adjustment must only
be performed by qualifi ed
service personnel.
•
Opening the amplifi er panel is
strictly prohibited except by
qualifi ed service personnel.
•
Always use a mains power connection
with protective earth. Failing to do
this may lead to personal injury.
Warning!
This equipment is capable of delivering sound
pressure levels in excess of 85 dB, which
may cause permanent hearing damage.
Gen 7060A+7070A+7071A 22.5.2002, 11:04 6
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