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
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 . 
@atmasphere maybe off topic but do you have a suggestion for a preamp to use with a passlab xa30.5 that will be used with 96db sensitive speakers?
Sure- one of our preamps will do that nicely :) (they're balanced).
The Pass amps are pretty easy to drive though- I would expect it to work with many different preamps.
I have Ascend Acoustics Sierra 2 speakers, and they sound great at lower volumes. I'm powering them with a Rega Elex-R, and live in a condo, so rarely listen at loud levels. I've had about eight pairs of good quality speakers over the years and these sound the best of any of them at lower volumes. Good luck.