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 flexible 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 configuration for LFE moni- toring. However, there are situations when the
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 film 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 first 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
•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 configurations 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
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 filled with liquid, such as vases on the subwoofer or near it.
•Servicing and adjustment must only be performed by qualified service personnel.
•Opening the amplifier panel is strictly prohibited except by qualified 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.
