Is Parasound on to something? Or, How important is crossover management in preamps?


How important is crossover management in mid-fi receiver?

I auditioned Parasound separates yesterday — P6 and A23+ and the dealer emphasized how useful it would be to be able to control the crossover *both* for the subwoofer (I have a Rel 328) and the bookshelves (TBD, but I'm looking at Dynaudios and Salk WOW1's). Not many preamps have this, and I'm wondering how important it is. I'm also quite interested in PS Audio's separates (Stellar Gaincell + S300) but they do not have these, nor do they have tone controls.

So how valuable is Parasound's controls? What is the significance (positive or negative) control over the crossover — especially of the *main* speakers themselves? The positive, I read, is that it (a) allows mains to do a more precise job by relieving them of the burden of the bottom end, and (b) it increase the efficacy of the power amp in driving the mains. Is there a negative? Is there something "improper" about limiting the demands on mains, especially given their designed frequency range?

As you can see, the answer to this question helps determine whether Parasound has a major value-adding feature in these crossover controls.

Obviously, at the end of the day, auditioning pre's and poweramps (or integrateds) is crucial, as is match to speakers, etc. But if this feature is very important for fitting sub and mains together — and fitting speakers to room environments — then it will help me weigh the Parasound or any other preamp with this feature.

P.S. To those who keep seeing my newbie questions, I hope they're not irksome. I'm posting so often because I'm researching purchases for a whole system, of some cost, and so I'm really digging into these questions about all aspects. And I'm having a blast.
128x128hilde45
I love how some people here will answer questions by COMPLETELY disregarding the question and offer their own completely unrelated set of rules that pertain exactly ZERO to alleviate the op’s confusion. Funny thing is their advice is shockingly unhelpful and wrong. Really getting tired of these self proclaimed "experts" and unfortunately they seem to be the most active members on this forum. Their goal being not to help but to confuse and muddle. My only advice, is that you really have to do your own research outside of the realms of this forum because the people that answer first, are usually the ones that i have just mentioned and as I have said, they are not helpful for the most part and until they choose to go away this site is almost useless.
Thanks Doug for weighing in. I may write to Salk. I appreciate the various views, and may just have to remain agnostic because I cannot sort out what's best. I'll go listen and consider my day to day needs. 
@hilde45 & @lukaszwk  Agreed that people with an axe to grind hurt the forums... disagreed that this makes the place worthless.  I've learned so much here.  If you hang out enough you can get a sense of who to trust... and learn a lot in the process.  

As a shortcut judgment...  always believe @almarg .  And if you click on a username you can go look at their last X posts and see what you think about their recent contributions.  
I do enjoy reading certain individual’s posts, people with actual engineering decree and knowledge surpassing 99.99% of people here, like Atmasphere’s posts but people like that are few and far in between. This places has slowly been losing its luster and usefulness, for me at least. But to each his own. If you can truly be selective as to who you listen to, it can still be a useful place at times. But I think I’ve had it. At least for awhile.