Just wanted to share my experience with Rega DAC (non R version, used on USB port) filters. There are 5 of them, differences are subtle and somewhat speaker/system dependent. YMMV.
1) the most extended from top to bottom, the most transparent and neutral. Midrange is a bit recessed for my tastes (very neutral), and can sound a touch bright. Tone overall is a touch brighter. I can easily understand why it is the default/preferred filter.
2) truncated on both top and bottom ends. Treble is rolled off. Midrange is forward and sounds darker. Non aggressive sound, can tame a bright system at the expense of frequency extremes. Sounds a bit lofi comparatively, but with a forward, lusher midrange
3) sounds just odd to me, I do not use
4) slight upper midrange lift and stronger bass
5) somewhat V shaped
1) the most extended from top to bottom, the most transparent and neutral. Midrange is a bit recessed for my tastes (very neutral), and can sound a touch bright. Tone overall is a touch brighter. I can easily understand why it is the default/preferred filter.
2) truncated on both top and bottom ends. Treble is rolled off. Midrange is forward and sounds darker. Non aggressive sound, can tame a bright system at the expense of frequency extremes. Sounds a bit lofi comparatively, but with a forward, lusher midrange
3) sounds just odd to me, I do not use
4) slight upper midrange lift and stronger bass
5) somewhat V shaped