Audio device testing software?

 I have just bought some new earphones, they say the frequency range is 20 - 20kHz (fairly standard).
I want to be able to test them so that I can ACTUALLY hear what 20 / 20kHz sounds like.
While I'm there I'd like to test my (beloved) Sony sound system.

Could I hook it up to a PC sound card and run some software or would the card drop the quality? *it is an el cheapo one.

I've already played loads o' Pink Floyd before anyone asks....

Re-design8 years ago
If you've been listening to Pink Floyd then you probably can't hear above about 10 k.  THat's what ruined my hearing.

But in anycase, Look for audio generator software.  There are lots that are free and will let you dial in the frequency that you want.  I don't see why an average computer running an average sound card won't be able to out put the low and high you are looking for.  But if you don't hear it the either you shoulda turned down the volume a long time ago (that's me) or your system won't output the freq's.

Good luck and "I'm sorry but you're just too darn loud".