This is a very brief overview of some of the differences in Pro Tools systems, there are many.
There are currently three versions of the Pro Tools software, each running on different hardware systems.
Pro Tools HD – For Digidesign TDM systems (HD Accel, 192 i/o, ICON)
Pro Tools LE – For Digidesign USB/Firewire Audio Interfaces (digi 003, MBox 2)
Pro Tools M-Powered – For M-Audio Audio Interfaces (Projectmix i/o, delta 1010)
Most functions are available on all versions and are mostly cross-compatable, some features change or are unavailable depending on the interface connected. Pro Tools M-Powered requires an iLock dongle as well as compatable M-Audio hardware. Pro Tools LE requires a Digidesign audio interface such as an Mbox to run. Pro Tools HD requires both a USB iLock key and Digidesign DSP cards to run.
The main difference between Pro Tools LE, M-Powered, and HD is that Pro Tools HD uses TDM (Time Division Multiplexing) to process the audio streams with DSP PCI cards, rather than Host-based processing. Another difference is the amount of audio tracks you can have in a session, PT LE is limited to only 32 voices (32 mono audio/16 stereo tracks) and in HD you can have hundreds (if you can afford to). There is also a difference in price, a huge difference in price.
PT LE and M-P both use RTAS (real-time audio suite) plugins, PT HD uses TDM plugins as well as RTAS if needed.
There are two upgrades for Pro Tools systems: Music Production Toolkit, and DV Toolkit.
