Mark Levinson N40 - Manual (Page 78)

5-12
Menu System Mark Levinson
settings, indicated by “sub #1” and “sub #2” in the menu system
when this option is selected.
Surround back and left subwoofer
Some installations require separate left and right subwoofers, rather
than two mono subwoofers. This is partly a matter of preference,
and sometimes a matter of speaker design philosophy. If your
system requires this approach as well as a surround back (Sb), select
“surround back & left sub” from the menu.
In this case, the aux 1 output becomes the surround back output to
be used with the amplifier that drives the surround back speaker.
The resulting room layout looks the same as in Figure 5-2 on page
5-9.
In this case, the aux 2 output becomes the left subwoofer output,
and contains all redirected bass from any speakers on the left side of
the room that are bass-limited; in addition, it contains one-half of
the redirected center channel bass (if any), and one-half of the low
frequency effects (LFE) channel (if any) in discrete multichannel
soundtracks.
To summarize, in this setting:
• The subwoofer channel becomes the right sub channel
• The aux 1 channel becomes the surround back channel
• The aux 2 channel becomes the left sub channel.
Crossovers Once you have defined what speakers are going to be used in the
main zone, you can further specify the nature of the crossovers
used with those speakers. Note that your options in this section of
the menu will vary somewhat, depending on how you elect to use
the aux channels. The menus update dynamically, to reflect how
you elect to use the available hardware.
If you are using THX-certified speakers…
If you are using THX-certified loudspeakers, you should use the
THX crossover frequency of 80 Hz and a low pass crossover slope of
24 dB/octave. These options are listed as 80 Hz, THX and 24dB/oct,
THX in the menu system as a reminder. Please make sure that if
your THX subwoofer has switches or controls to give you different
options, make sure that those switches/controls are in the “THX”
position. This will ensure the correct alignment to the main
speakers.
Frequency
For each logical group of loudspeakers other than subwoofers, you
are given a choice as to both the crossover frequency and the cross-