Encoding 6ch AAC

[rtjnyoface]

What could we describe as an acceptable br for encoding 6ch aac for different types of movies such as mainly dialogue movies and action movies?

Thus far I have been encoding my action movies at ~240 and dialogue at ~200. Anyone else have any ideas? I know this is highly subjective due to hearing differences amongst us all but I'm hoping we could come up with some suggestions.

From the AAC FAQ the suggested br is 320 for 6ch (for LC AAC) but I assume this might be overkill. Anyone have any comments or suggestions?

[Inspector.Gadget]

Run the original ac3 or DTS against the encoded AAC using foobar2000's ABX comparator. Use the lowest bitrate at which you cannot distinguish the two.

[tebasuna51]

Use variable bitrate quality based with -q between 0.32 and 0.35
Less than 0.32 is AAC-HE maybe not compatible with some player, more than 0.35 I think is excesive for lossy sources.

[Midzuki]

320kbps for 5.1 LC-AAC seems quite fair, actually. Overkill would be to give 256kbps for each channel (maximum value allowed by the specs).

[MatLz]

Downsampling the samplerate to 44.1khz or 32khz is also possible for lowbitrates usage.