Yes, thanks Dave (and Frank!) for the informative posts - nice job
I'll chime in on a couple of these from mr. daly and rockridge:
1)
So I always assumed the signal was dithered from 48bits to 24 bits at the output of every plugin.... It is up to the TDM plug-ins themselves, and not all do this (many do internal processing at 48-bit, but don't necessarily add dither to go down to 24-bits). As this dither would be at roughly -144 dB it is often a better choice to avoid the extra processor cycles required. The "dithered" mixer will add dither at its final output stage on any given output path, but this only happens once at the 48->24 bit truncation.
As far as the native mix engine, it is not significantly different (in terms of signal path) with native PT10 systems. However, as Dave mentioned the new HDX system is different from legacy HD/TDM systems, one advantage being that audio is kept at 32-bit between the host CPU and the HDX cards, so you don't lose anything (as opposed to needing to convert to 24-bit fixed point when sending the audio signals to the HD/TDM cards).
Re: coding in different languages -- fortunately we are able to keep the PT10 system mostly to high level languages (C/C++) for both the host system and HDX/DSP plug-ins, although the processors are different for the new plug-ins so a bit of tweaking at a lower level is sometimes needed to get the very best performance. And of course FPGA coding is a different ballgame as well (!)
-Toby Dunn
Avid Engineering