The surround speakers get whatever frequencies are part of those channels on the disc, but modified according to your bass management settings.
If you set them to Small and use an 80 Hz xover in your receiver's bass management settings, they will get roughly 80 Hz and above only. That is the purpose of bass management - to direct the frequencies which are not handled well by other speakers to the subwoofer which is purposefully designed to handle just the low frequencies.
