Speaker Problem

[Mobius]

Hey, I've got a weird problem. Basically some parts of my mp3's I'm unable to hear, when they used to be fine. The song plays fine, then it will get to a certain bit (e.g. when lots of drums begin playing) and it will go very quiet so I can only hear it when I hold the speaker up to my ear. Also some of my mp3's sound different now as though its all been made a lower tone or something.
Is this a speaker problem, or have I fiddled with the volume controls?

Thanks

 

[Clown]

Is this all of your MP3s or just the ones you got from KaZaA?

 

[old.user4556]

Ah Clown, genius reply, brought a smile to my face

 

[Mobius]

Hehe, I thought it was corrupt mp3's but it isn't. They work fine on another system.

 

[WPKenny]

You haven't somehow managed to install a plug-in that controls the volume dynamically have you? Like when the music gets louder, the pc turns the volume down?