I had a similar need in my workshop. I am very happy with:
- Speakers: 1st Generation B&W 686’s (Pushed close to the wall)
- Amp: 1979 Yamaha CA-410 II
- Volume: Set straight up to 5
- Loudness: Set straight up to 5
- Tone Controls: FLAT
I can listen to Steely Dan on this for 8hrs straight and be totally happy...
There is NO need for "Audiophile / Expensive" gear to accomplish 60-65db listening levels for all the Fletcher/Loudness/"V" shape information already listed above.
Any Yamaha w/"Loudness" solution will do, and some B&W's... :-)