no 4-8 ohm ga bor. just 4 ohm, 6 ohm and 8 ohm only. it's written at the back said 4-8 ohm? If using all 4 ohm speaker, may be the amp unable to push in such high volume (-10dB) and overloaded.
one more thing is if using -10dB, I think the volume should be too high, for marantz, I'm using -20dB max, how come ching use -10dB? That why the machine overload.
That film were so dynamic, let's turn down the volume. most AV amp were not able to handle 4 ohm speaker, the problem can be solve if you add power amp or change speaker other than 4 ohm.