First make sure all speakers are set to small. Don' t use the sub plus feature. Second, if the sub level in the avr is over + 6, then the sub gain is to low. Don't use standby on the sub, keep it on. Four, consider using a Y connector for the sub.
Klipsch RF 7 based HT 7.4, Pioneer SC 35, Acurus 200 Five, Dayton 18 Ultimxa Dual Sub Cab(2), Dayton 18 Ultimax Large Vented Sub Cab (2), on Berhinger I Nuke DPS amps, Samsung BDP F 7500, Asus/My Book Live HPC 4 TB
Yaquin VK 2100 amp, McIntosh XR 5 speakers, Samsung BDP F 7500