hiss + popping (light crackling) when volume turned up with no sound

[Johnny B]

Hello all,

When I turn up the volume on my computer speakers pretty close to
full, i hear the hiss sound (which i've read is normal ground
noise)...however, i also hear some crackling or popping like sound
going on if i put my ear close the speaker. i'm not quite sure if
this existed before...because i never tried this prior to playing my
speakers pretty loud over the weekend. i might add that they sound
fine when playing at regular level, or even cranked up a bit. i just
want to know if this is normal or if it sounds like some damage was
done somewhere. please advise...thanks!