audio drivers and sound cards for speech processing

HI !
I use Audacity for the enhancement of the speech signal. In particular, Audacity help me in the noise reduction and to reach a better words articulation rate using the ChangeTempo effect. However, it sometimes seems to me that changing player (for example Windows Media Player or VLC) some words begin more clear.
This happens using the integrated audio card of my PC.

My question is: why ? Is maybe a wrong sensation of my brain ? I know that we hear with brain.
Or it could be maybe due to a different way the programs set up the sound card ?
Please, I apologize with you for the probably stupid last question.

However, can you tell me if ALSA drivers are a good choice ?
Maybe are there sound card with proprietary drivers that work better than ALSA ?
Can you tip professional audio cards for the speech signal enhancement ?

Many thanks in advance.


Excuse me again.
I would like be more clear about the questions posed in my post.
I take as example the ChangeTime effect.
When a user apply the analogous effect using Windows Media Player or VLC maybe do these programs do a sort of pre- o post- processing (some kind of filtering) so that the sound appears more beautifull ?
I don’t know this.

Windows Media Player & VLC both have real-time equalizers built-in.
Changing the equalization can make voices easier to understand.