Yeah, it should hopefully be your speakers creating the hiss.
Though cbheck these options first. Find the sound volume logo in the task bar and open it up.
First check that the sound volume isn't set all the way up, and instead higher the volume using the speakers, does this help?
Next, check that you don't have a microphone plugged in and it is recieving stuff and sending it out through speakers. So mute the microphone if so.
If it isn't listed, go to Options, Properties and select Microphone from the list and press okay.
If all this isn't causing it, a good Creative set is never bad
You are looking for ones with good wattage on each speaker, one that has the highest sound to noise ratio, and one that has the lowest bass response (50 and lower is good, since 20hz is the lowest we can hear).
Hope these suggestions help