A typical main speakers + subwoofer configuration would either use:
• A dedicated crossover frequency splitting that sends the bass to the sub and the remain to the main speakers - with the disadvantage that the filter artifacts spoil the sound quality.
• Or no filtering for the main speakers at all, just adding the sub on top.
The main speakers would still need to deliver the full bass energy, trying to produce frequencies that they are not capable of.
This minimizes the possible advantage a sub can give in extension and clarity.
The basic idea for a solution is simple:
• Connect both mains AND sub to the same stereo output, e.g. by using both the XLR and RCA out.
• To reduce the load on the main speakers/amp, use ADI-2’s EQ’s shelving filter to bring down the low frequencies.
• Now fill the missing bass with the sub.
This way only one stereo output is needed, opposed to when a real 2-way crossover is emulated, which would only be possible with ADI-2 Pro’s dual outputs anyway, and is quite uncomfortable in multiple ways.
The other advantages:
• The main speakers still partly contribute to the bass, improving the bass quality and give a smooth transition to the sub.
• The still multiple sources for the bass (instead of a single sub) give a better room coupling, reducing unwanted room resonances / modes.
• A soft shelving filter does not, like a high/low pass filter of a normal x-over with steep cuts, introduce a bad impuls- and phase response.
And, even a moderate bass reduction of only 6 dB reduces main speakers driver excursion and power amp load to 1/4, this can be a night and day difference in clarity.
Here is a setup guide.
It reads a bit lengthy, but in fact is straight forward, go for “case1”:
https://forum.rme-audio.de/viewtopic.ph … 12#p155312
The guide even explains the use of an easy to obtain and inexpensive measurement tool, which by itself improves the sound quality by a significant margin.