Full detailed sound at 30 - 40 - 50 dB

Lowering ambient noise as much as possible is indeed a first requisite. In a new house you can specify sound proofing glass for the windows, muffled ventilation, a quieter heating system, but in an existing house these are all hard/expensive to do. Even, so there may well be possibilities.

The headphone suggestion is a good one, it cures a lot of woes and can give you some great listening sessions, also keep in mind that the speakers are like an open window to your upstream components and are not going to cure any of their short comings. I myself have my system set up, in near field, such as to render all the dynamics and presence I need at low volumes. Most my listening sessions are late at night into early morning, while grandson is asleep and can honestly say that I don’t miss the higher volume but do crank it up when I can but absolutely don't miss the higher volumes when I can't.

Thanks for the suggestions guys. Ordering a Loki now, I’ll let you know how it goes. I think that’s the ticket.

I use only two sources: Airplay streaming through a DAC and a Rega Planet CD Player. I can EQ the streaming on my computer and the Loki will go in line with the CD player.

Cheers!

Also sitting closer to the speakers is definitely a helpful tip I’ve been using already - sometimes I just want to sit on the couch though :)

Note that creating an unusually quiet environment for a baby can condition the baby to not be able to sleep without utter quiet, sometimes not a good thing. I don't imply anyone should expect a baby to sleep through excessive loudness, but I've seen this happen with one of our grandkids…in a largish house everyone having to whisper if the baby's sleeping…actually a first in my wife's and my experience (raised 3 kids between us), and because we're "all knowing" grandparents, our expertise is, of course, unquestionable, although we could be wrong about everything as all kids are different.