Full detailed sound at 30 - 40 - 50 dB


I love the nuance you can hear when listening to music at loud volumes, but unless no one is home, it’s not considerate or feasible to listen at such high volumes. Plus I just had a baby so everyone is always home and volume levels are limited to 40ish dBs. 

Any recommendations for getting the most detail at these volumes? Additional gear or recommended integrated amps?

My NAD 7175PE has a loudness button which boosts the treble and bass a little, and that certainly helps things in the Kitchen. 

My living room amp is a Rega Brio-R which doesn’t have any tone controls. 

Any thoughts? Thanks!
leemaze
I recommend you move the baby into the audio room and acclimate the kid to your hobby now. I learned to fall asleep to a bunch of dudes wailing on guitars in the next room...and look where it got me...posting bad advice on Audiogon. :-)
Congratulations on having a baby. One of life's great blessings.
Which First Watt would you recommend to the owner of high efficiency speakers (101db, 16 Ohm) ? Currently using push-pull tube amp designed (OEM) by Trafomatic Audio for WLM Acoustic back in the days.
A lot depends on your preamp as the single gain stage units need more drive.  I'd be looking at one of the 20 or 25W units since they will be making less power than that into 16 ohms.

FWIW a speaker like that is ideal for tubes. We make a 30-watt/ch OTL that would work great on that.
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A subwoofer will do the trick . You will most likely feel bass is missing at those low volumes . You can listen at low background levels with a sub and get the full frequency range .