TDB - "true dynamic bevavior" takes care of the natural and intuitive way how XPression responds to incoming dynamic information.
By breaking down samples into seperate components like "soft / loud", "attack / sustain", "legato / non legato", "pitch / noise", "original pitch / deviation from original pitch", and so on it becomes possible to manipulate complex changes in sound selectively in individual cells. TDB automatically recognizes the relevant parameters to be modulated while doing musical phrasing. It's not just simply opening a filter or crossfading between samples as most other synths do.
TDB is even capable of creating sound components that were not even existing in the original sample if the musical context is asking for it.
To be able to handle such extensive manipulations in sound the samples have to be recorded and edited very carefully. Conventional samples do usually not meet these high standards.
Now, what's the difference between a good musician and a machine?
If you input the same parameters into a machine it will always reproduce the exact same result. But even the best musician will not be able to reproduce the same note 100% identically without any small variations. Some of these happen accidentally and some of them are well intended. These slight deviations make the music become alive and "human".
XPression varies - in a controlled way - certain parameters so that no note sounds exactly like the last one - even when repeating the same note. It's not simply rotating between two or three samples that keep repeating again as others do. It's varying single components of the sound. This way you'll end up with a huge but subtle variety of sound elements. On top of this XPression always follows the intuition of the musician.
Of course XPression can not and does not want to replace the expressiveness of a good musician. However XPression provides a tool for the creative musician to realize his musical intentions according to his choices - without beeing held back by the limitations of his sound generator.
TDB has an immense potential and is just at it's beginning. For this reason TDB will constantly be developed further. Free software updates will always keep you up with the current enhancements.