All of this conversation assumes low frequency sounds are coded for surround channels. In a DD usage, why would any sound engineer code such LF sound for surround channels when they KNOW that surround speakers do not have the capability (for consumers at home or speakers in the theatre) and when they know that subwoofers included in these systems are used for this very purpose?
The LF sound is coded to the .1 channel according to the design idea of a 5.1 system.
The hiss you hear is likely b/c there is no sound there at all.
The surrounds should play the higher audible frequencies during a LF noise to trick the ear into thinking the LF noise is actually coming from the rear or the sides, but that's about it.
Surround speakers in HT are not designed as full range channels and neither is the centre.
