Is it normal that i should get more hissing out of my central speakers than others?

[BoomAM]

Hi,
Ive just noticed that i`m getting more hissing out of my Central speakers than my others.Is that normal?

My Sound card, Creative Labs SoundBlaster Audigy 1 OEM
My Speakers, Creative Labs Inspire 5.1 5300

To be honest, ive never noticed it in the past, could it be caused by the new Audigy drivers, cos several people have noticed that the sound has less bass in it. Could more hissing be another "problem" with them?

Thanks in advance.