Any self-noise being present, even without anything playing is totally unacceptable and reveals the compromises being made during developement. Few companies like HEDD uses actual quality amps (ICEPower), and that's only on their TOTL. Even Genelec rates the self-noise on the 80x0 line to be 10dB@1m.
Age related hearing loss and a listening room with a bad noise floor also certainly affect the opinions on these speakers (some people claim that the JBL 305s don't hiss?)
Anyways, what speakers does OP have? The worst case of audiable hiss I've heard was some Presonus speakers, being audiable from 3m away.