15
AES/EBU Channel
An AES/EBU signal normally carries two audio channels in what are called subframes A and B. The “AES/
EBU CHANNEL” switch selects if the LFE signal is designated to subframe A or B.
LFE Bandwidth
The LFE input can be set to two frequency ranges: 19 to 85 Hz or 19 to 10 Hz using the “LFE BANDWIDTH”
switch. Signal content in the LFE signal above the frequency value selected on the “LFE BANDWIDTH”
switch is either not reproduced or is redirected (see below). See also “Typical applications of different LFE
bandwidth settings” below.
Redirect
Using redirection allows the LFE channel to be monitored as a full-bandwidth audio channel. If the LFE
signal includes content higher than 10 Hz, it can be monitored using the “Redirect” function. This function
allows rerouting of LFE signal above 85 Hz to the front center loudspeaker. This rerouted LFE content is
known as the redirected LFE signal.
Setting the “REDIRECT” switch to the “ON” position activates the redirect function and it can only be
activated if the “LFE BANDWIDTH” switch is set to “85”.
The redirected LFE signal is added to the audio signal contained in the other subframe of the AES/EBU
audio cable connected to INPUT 4. Typically the LFE channel is paired with the Front Center channel, so
one of the subframes of OUTPUT 4 carries the sum of the redirected LFE signal and the center channel
signal. OUTPUT 4 should then be connected to the Front Center loudspeaker.
Subwoofer input 4
Subwoofer output 4
Subframe A
Subframe B
Subframe A
Subframe B
Center signal
LFE signal
redirected LFE
signal
LFE signal
Center signal
redirected LFE
signal
LFE +10 dB
In Dolby Digital and DTS encoding formats the LFE channel is monitored with +10 dB gain relative to the
main channels. The object is to increase the headroom in the recorded signals. Surround sound decoders
may automatically add +10 dB of LFE gain to restore the level balance.
The “LFE +10 dB” function of the DSP subwoofers is designed to add the +10 dB of gain to the LFE
channel in the production stage if it is not already done by the source connected to the monitoring system,
