For each 6dB you are losing a bit of resolution, so, if you play Redbook 16 bit stuff do attenuate AFTER the DAC.
I monitored my playing of Mahler 2 this afternoon. At my seat the range was from 44 dB to 94. Most passages were at about 60 to 65, moderate crescendos at 75 to 80 dB, the 95 was a hard transient. Classical symphonies live can be as much as a 60 dB range.
On a CD a 50 dB range is 8+ bits so you are left with an 8 bit recording for the quiet parts. This is why the 24 bit recordings of wide range music is such an improvement, the quiet, slow, passages can have an ethereal quality that CDs cannot match.
I also listened to the Op. 132 quartet, that was mainly in the 55 to 65 range, some pp passages down in the 50s. Parts of the Heileger gesaang even down in the 40s.