The real comparison would be the D1 vs the new Tablette Anniversary. The Anniversary is a big improvement over the older Sig 50's.
As to which one is better, it will all depend on what amp, what size room, other equipment, and room setup. Never underestimate the importance of System Synergy. One may be a "better" model in the line up but that doesn't mean it will sound better to your ears.
As to which one is better, it will all depend on what amp, what size room, other equipment, and room setup. Never underestimate the importance of System Synergy. One may be a "better" model in the line up but that doesn't mean it will sound better to your ears.