DIRAC is free - well the trial is .. all you require is a Umik1 mic ($70 from miniDSP) and that in itself is a bargain purchase as you can measure the room with a calibrated mic..
Just try it , the cost is pennies compared to what some of us spend on a cable...
Lowbass DSP is almost a given for any system and room , unless you happen to luck on a speaker/sitting position that is serendipity and often the best place for bass is not the best place to listen to the rest.
Get the bottom end under 200hz right , you can passively treat for the rest.. passive treatment for a +10db hump at , lets say , 60hz is almost impossible to do.
If you have taken the time and money to spend on a megabuck system , get it right...
I actually redid my whole listening room with extensive treatments and what motivated me to do so was my speakers (g1's)
If you have a dedicated room , your attack is multipronged.. passive treatment , active treatment , bass distribution , DSP , eq etc... you will be amazed at the difference.
with a dual purpose room , you are somewhat limited and if you cannot get treatments or optimal positioning in there.. go DSP
Ignore arguments based on wide area listening position (HT) premises , for most of us with 2 chan audio , only the sweet spot counts.
there is no universal truth or reference for ANY recorded work .. no one barring the guy at the mastering desk knows what the thing actually sounded like .. reproduced music is nowhere near to anything live.. all it has to do is give you the illusion of "being there" and using eq/tone control in the chain is perfectly ok if it makes that illusion seem more real .. crossovers are equalisers , RIAA stages are equalisers ... speakers are equalisers ..mastering used equalisers .
At the end of it all , DSP makes a much bigger change than any box swapping does.. just try it.
As to target curves , well they are all taste based .. no one corrects for flat at listening position (unless you like no bass and really hot treble)