I do my mixing & mastering most of the time in avid protools hd using a variety of decent outboard gear connected via mytek converters clocked by an apogee big ben; benefiting from the
advantages of protools hd while at the same time implementing any other desired daw.
over the years I have checked out many different converters and quite a few system clocks- and concluded: both are crucial for good results. sometimes it is very impressive how switching from
e.g. a mytek clock to an apogee clock will slightly alter the overall character of a mix.