MartinLogan Depth subwoofer - Manual (Page 10)

10 Connections and Control Settings
This setup is recommended if your Depth will be used in a
2-channel only system and you intend to use the Depth’s
High Pass Filter Out.
Signal Connection (see figure 10):
1 Connect the left and right outputs of your preamplifier to
the left and right inputs of the Depth using quality RCA
interconnects.
2 Connect the left and right outputs of your Depth to the
left and right inputs of your amplifier using quality RCA
interconnects.
Recommended Control Settings (see figure 3):
1 Set the controls as recommended on page 6.
2 The High Pass Filter: Out switch should be set, at the user’s
discretion, to the option with the best sounding result.
As a general rule, if your main loudspeakers are bookshelf
speakers, set the High Pass Filter: Out to 70Hz. Likewise,
40Hz for floorstanding loudspeakers. Use ‘None’, if you
want to pass an unaltered signal out of the Depth.
3 At this time the Depth’s Low Pass Filter should be set to
approximately 70% of your main loudspeakers lowest
frequency response—make note of this number, as you
will use it below to determine the correct setting for
your low pass filter.
If the High Pass Filter: Out is set to ‘None’, the Low Pass
Filter should remain at approximately 70% of your loud-
speakers lowest frequency response.
If the High Pass Filter: Out is set to 40Hz, the Low Pass
Filter should be set to 35Hz or 70%, whichever is greater.
If the High Pass Filter: Out is set to ‘70Hz’, the Low Pass
Filter should be set to 55Hz or 70%, whichever is greater.
Why the Filters Are Not Equal
You may have noticed the recommended setting procedure
above does not advise setting the Low Pass Filter and High
Pass Filter: Out to the same frequency. This is because you
are setting the filter points, not the crossover point. Between
20Hz and 100Hz, as the subwoofers output decreases, the
loudspeakers output increases. For a seamless crossover of
these two slopes, the summation of their two values, at any
given frequency, should add to maintain a level output. By
correctly setting your High Pass Out and Low Pass filters,
this result can easily be achieved (see figure 11).
Figure 10. Signal connection for 2-channel mode with 2-channel output.
Figure 11. Filters settings for a loudspeaker with a Low End of 56Hz.
2-Channel Mode With 2-Channel Output