I have not heard the D-48, but I own the D-40r.
I have heard the Proac dome speakers and they are good but the ribbon tweeter IMO is a better sound, It integrates very well with the mid/bass driver and there is no discontinuity
I have heard the Proac dome speakers and they are good but the ribbon tweeter IMO is a better sound, It integrates very well with the mid/bass driver and there is no discontinuity