This is my sound card:

That's an ISA turtle beach Tropez plus.

It was working just fine until yesterday, but now I'm having this weird issue with speech/digital audio in games.
The speech sounds in games like Sam & Max Hit the Road Classic and Wolfenstein 3D became high pitched. It's like the tempo is twice as fast as the normally should be.

All the music plays fine, it's only the speech that becomes weird and barely understandable.

I tested with another sound blaster compatible card and the speech is ok, so I guess the problem is in the card? What should I do?

**EDIT
This is happening with every game that uses digitalized sounds, not only digitalized speech.

Thanks in advance.