There’s been a lot said about Pro Tools 11 being a 64 bit application but not a lot about the implications on the audio path.
Our buddy Colin over at McDSP has an excellent article about it on his site - here’s a snippet…
In professional audio production, signal quality is paramount. Naturally then, McDSP AAX plug-ins (DSP and Native) make the most of what is possible in Pro Tools 10 (and 11). Although the Pro Tools 10 audio path is only 32 bits, within a McDSP plug-in, we’re adding another 32 bits of precision to give the discerning user a more accurate, dynamic processing experience. Using this approach, McDSP plug-ins are able to provide greater control flexibility and increased fidelity for the best sound possible. For example, the AAX version of the FilterBank E606 plug-in has increased frequency control ranges – more than the original E6! This was only possible with the capability of the new HDX hardware and the flexibility of the AAX plug-in format.
This design is similar to what was done for our TDM and RTAS plug-in line. Both formats leveraged the double precision capabilities available (48-bit for TDM, 64-bit for host CPU processing). McDSP AAX plug-ins (DSP and Native) use similar double precision techniques, but can now do so at the 64-bit level for both DSP-based and Native-based processing.