How are you handling the seek table data? That will need to be recalculated for each partial submit.

Check to see if any other app or service is using port 80. (Current versions of XACT use this port exclusivly for auditioning.) If so, try shutting down the app or temporarily stopping the service so port 80 is free. 

How being enabled is handled is done by the effect itself. ''BOOL IsEnabled'' is a parameter of the IXAPO::Process() call (the base interface defined in XAPO.h). In other words it's totally up to the custom effect's implementation what to do whatever it needs to do for the given state. The InitialState is just that, with EnableEffect and ...

XAudio2 is an API aimed at games, so it needs to be able to handle multiple voices better, as in hundreds of voices at a time. Windows Media Player plays one voice, so it can use a much higher quality, but much more CPU intensive, samplerate converter without worrying about CPU issues. That's a possible reason the quality seems different. It's a ...

GetPosition and XAUDIO2_POSITION have been removed. They are obviously still referenced in the docs. (not good, but we'll get that fixed ASAP)   So, yes, the docs are out of date. GetState does return the number of samples played on the voice, so that would be your best bet as a replacement. There are a lot of reason it's better to not ...