I know TDM is for their HD system and LE is for the other hardware (at least I think), but that's about all I know (or think). What is the difference? What does TDM and LE stand for or mean.
Thank you

Protools TDM are their Professional variant of DAW, where a lot of the actual work i.e. d.s.p signal processing takes place outside the computer and inside varoius external boxes/interfaces you must buy.

This means you must buy both software and special hardware from Digidesign. This is very expensive gear.

Prootols LE DONT need any external gear to work ( in principle ) using mainly the CPU on your computer to do most of the processing.

However you will still need some kind of audiointerface with Prootools LE - you can use DIGI:s own
-001 002 or MBox.

Cheers: Dixiechicken

Also PT LE is not expandable, the TDM systems are modular.

LE=light edition 32 tracks max,
PTHD|3 system 96 tracks, higher quality effects and bussing, integration with Avid film/video systems.

PTHD|1 systems start at $7000.

this is partially true... actually the processing is done in the computer with TDM but with very expensive DSP PCI cards sometimes called Farm cards etc. The external boxes usually are just for the audio I/O's.

And actually LE does need special external gear to work.... it needs the audio interface such as Mbox or Digi001 or Digi002 for sound management and I/O but yes it uses CPU for audio processing mostly.

ProTools Free is the software that doesn't require any special hardware to work but its very limited.

Is it true that you have to use Digidesign hardware to be able to use ProTools?

YES unless you download the free version called ProTools Free as noted above

Yeah, but that doesn't work with OS X!

i don't recall OSX being a part of the equation as it was never mentioned

I know, that was just a statement from me because I use OSX.

i see