A significant reason for maintaining a 32-bit release right now is compatibility with existing plug-ins. The short answer is that the bulk of third-party effects are still 32-bit, and there is no simple compatibility layer between 32-bit and 64-bit effects. We absolutely understand the desire for 64-bit support in order to handle larger sessions, but to be completely honest, there HASN'T been a significant demand for 64-bit support from our customer surveys or requests. In addition, the testing necessary to validate both 32-bit and 64-bit builds would have pushed this release further ahead. Finally, for the initial release of Audition on the Mac, we wanted to ensure compatibility with ALL Intel-based Macs.
I don't want there to be any misunderstanding - 64-bit IS important going forward and will be a focus as we continue development for all platforms.
More of a question...
I understand the benefits of a 64-bit app, especially on osx and primarily for larger multitrack sessions including synths and the like. Is there a huge benefit of utilizing that much more memory for mastering applications (which AA is primarily aimed at) while dealing with only a limited number of tracks?
A drawback to a 64-bit only application is that no 32-bit VST plug-ins will work in a 64-bit application. For example, see Premiere Pro which is 64-bit only.