NM_RREAR
chancfg_t ch_rsurr_4 = { (1 << 3), NM_RREAR, 0 };
chancfg_t ch_rsurr_5 = { CH_RSURR, NM_RREAR, 0 };
chancfg_t ch_rrear_7 = { CH_RREAR, NM_RREAR, 0 };