IDT audio driver on ENVY 17 2xxx conundrum

I am confused as to what is problem here with my IDT audio drivers or maybe hardware - can anyone help please??

I've installed the IDT audio drivers onto my ENVY 17 2280NR laptop and when I select IDT Speakers / HP as default from the Sound Playback devices menu (see attached image below where I have some music playing in background on XBMC) nothing comes out of the speakers but the green volume bar shows values. I can not hear anything, unless I plug in a set of headphones and listen through the headphones.

** Then if I simply select the IDT Communications Headphones below this and choose test the test noise plays briefly, through the headphones AND whatever background music I have playing plays though the laptop speakers as I wanted to begin with - but it only lasts as long as the test sound plays for! I.e. the only way I can get sound out of the laptop speakers is when I mouse click a request such as test the IDT communications headphones playback device or if I mouse click the volume mixer and change settings there for the IDT communications headphones. When the mouse actions are complete the sound stops coming through the laptop speakers although the green volume gauge shows volume is there, I just cannot hear it. Any clues please?

 

This guy on YouTube Fix sound on Dell Studio XPS 1640. - YouTube has an exact same problem as me with his Dell IDT audio. If I follow his tip to record with the microphone settings and playback thro headphone then the sound comes out the speakers again! Why is this and what is the fix I wonder?

 

Well that's disappointing - was hoping for a lead on this annoying silence on my HP ENVY 17 2280NR