I live in an 1100 sq ft two story co-op apartment. I'm on the top floor and the walls are reasonably thick, but the floor is crappy and the woman below me would complain if too loud. Of course, I still will decouple the mains and the subs from the floor as best I can, for better sound quality, not just for her sake. But as I said, I rather doubt I'd be doing SPLs much above ~ 65db @ 1kHz from 10 ft away.
What worries me is that given how hearing sensitivity changes vs frequency, wouldn't I still need some kind of Fletcher-Munson based Windows plug-in (all music via pc; no CDs, vinyl or tape), even if the only time that I likely change listening levels is to lower it?
I find a fletcher-munson (or equivalent) loudness/late night listening mode invaluable...
However - the level of "adjustment" needs to either be based on calibrated reference levels (as provided by movies under normal circumstances) - or, primarily for music - needs to be manually adjustable for material where there is no reference level (like old style integrated amps of the 1980's that had a "loudness" dial)
If you have an AVR/AVP with Audyssey, it will also include DynamicEQ and DynamicVol... which do the job (EQ does the Loudness, DynVol does compression, which can be usefull late at night).
Other AVR/AVP's with Dolby Surround will have Dolby's Late Night and Loudness modes, if they have THX processing, then THX also has a fletcher munson "loudness" mode.
All the above are of variable value for music, due to the lack of a valid reference level... (unless you can vary the level at the source - but that is done digitally, and risks potentially degrading the dynamic range.... still... )
So options are available depending on how you design & setup your rig...
Although the core of my setup is a Windows10 HTPC, I do not do any processing/filtering on the source, as I leave that to the AVR/AVP.... they key thing being, there is no way (without massive amounts of messing about, and expense) - to get a proper decoded, mixer applied output from a Win PC into 5.1.4 channels (my setup)... for a base/basic 5.1 or 7.1 setup it is much more viable - but even then, the cost of the DAC to output those channels, is pretty much the same as the cost of an AVR/AVP.
So although everything I play comes from the PC.... I simply feed the raw output in its original format, straight out to the AVR/AVP, and let it do all the decoding, mixing, and EQ.
Last time I checked what it would take to do everything the AVR does on my PC, it ended up costing substantially more than the AVR.... in addition to which integrating the software, and then keeping it stable, every time any of the various bits of software involved get an update, is a headache I didn't want... every few months there will be a glitch when some driver or software is updated... and I still need to do troubleshooting several times a year, but its an order of magnitude less than if I tried to do everything on the PC... as a PC guy since the 80's that's a bit sad... but it is also pragmatic, and ensures that other members of the household can reliably enjoy the setup too.