It has taken me quite a bit to get my sub integrated. Not as easy as I thought originally. The absolute biggest reason to get a sub I can't do... Cut off LF to mains and send to sub. I have an integrated with sub out and there is no way to cut off LF passing thru. I can put a Crossover to speakers, but that leaves amp wasting power. I can cut off LF using streaming programs, but that cuts off to sub.
It made integration much harder. I finally found the right position, sub Crossover matched to speaker, and proper phase. Speakers are 1st order and until I figured out I had to match sub it was terrible. Even offsetting phase to match didn't help. It basically renders both without a LF cutoff. Mains naturally roll off and sub rolls off at -6db. Changing Crossover point does hardly anything. But it is the only way to not have nulls and to not localize my sub. It sounds fantastic. All bass is coming from mains... Who knows if it can be better... And my mains are ported, but sub is sealed. The only way to properly do would be a some DSP/Crossover between DAC and amp with a sub out or bypass out to send to sub. Sub has cutoff so who cares if it receives full range signal. But I just can't imagine adding a box would be a good thing. It is quite maddening actually.