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[syndromeofadown]

Maybe this makes sense, but it seems strange to me so i thought I would ask if this is normal behavior.

I have switched a PC with surround speakers to Linux. DAC is MiniDSP Flex HTx. It is 8 channel DAC but my speakers are 5.1.

Here is how MC is assigning the channels in different scenarios:
(The numbers are the numbered outputs on the DAC)

MC set to 7.1 output, playing 8 channels
1 Left
2 Right
3 Left Rear
4 Right Rear
5 Center
6 LFE
7 Left Surround (Side)
8 Right Surround (Side)

MC set to 7.1 output, playing 6 channels
1 Left
2 Right
3 Left Surround (Side)
4 Right Surround (Side)
5 Center
6 LFE
7 empty
8 empty

MC set to 5.1 output, playing 6 channels
1 Left
2 Right
3 Left Surround (Side)
4 Right Surround (Side)
5 Center
6 LFE

MC set to 5.1 output, playing 8 channels
1 Left
2 Right
3 Left Surround (Side) + Left Rear
4 Right Surround (Side) + Right Rear
5 Center
6 LFE

and none of these match the output when testing channels in linux audio settings.

Does it make sense that when MC output is set to 7.1, the outputs for 'Left Surround' and 'Right Surround' change depending on if 6 channels or 8 channels are playing? Is MC outputting incorrectly or is MC intentionally moving the side surrounds to the rear speakers when there is only 6 channels playing with 7.1 output?

I understand that channel order for outputs can change depending on if are using 6 channel output or 8 channel output, but it does not make sense to me that the channel order changes depending on if you are playing a 6 channel or 8 channel file.

If i make a zone with 7.1 channels and play MC 7.1 calibration audio I get this:
(The numbers are the numbered outputs on the DAC)
3 Rear Left (used in 7.1) (channel 5)
4 Rear right (used in 7.1) (channel 6)

If i make a zone with 7.1 channels and play MC 5.1 calibration audio I get this:
(The numbers are the numbered outputs on the DAC)
3 Surround Left (channel 5)
4 surround Right (channel 6)

Again, is it intentional that when playing 5.1 sound with MC set to 7.1 output that the Left Surround (Side), and Right Surround (Side) come out the rear channels?

Thanks

[Hendrik]

This is just how 7.1 channel layouts are defined, they have rears in front of the sides. If you enable JRSS upmixing, I'm pretty sure it'll handle the 5.1 -> 7.1 case properly as well (the "no upmixing" mode is specifically designed to not touch channels at all, for better or worse). Usually if you use a HDMI audio receiver, it would ordinarily map the channel to the right speakers automatically, hence why we stick to the standardized channel ordering.

But considering you only have 5.1 speakers anyway, the second two sets should be how output is setup for your speakers, and that seems to have no trouble?

(Note that your orders are somewhat peculiar to begin with, usually its L R C LFE Lrear Rrear Lside Rside)

[mwillems]

Maybe this makes sense, but it seems strange to me so i thought I would ask if this is normal behavior.

I have switched a PC with surround speakers to Linux. DAC is MiniDSP Flex HTx. It is 8 channel DAC but my speakers are 5.1.

Here is how MC is assigning the channels in different scenarios:
(The numbers are the numbered outputs on the DAC)

MC set to 7.1 output, playing 8 channels
1 Left
2 Right
3 Left Rear
4 Right Rear
5 Center
6 LFE
7 Left Surround (Side)
8 Right Surround (Side)

MC set to 7.1 output, playing 6 channels
1 Left
2 Right
3 Left Surround (Side)
4 Right Surround (Side)
5 Center
6 LFE
7 empty
8 empty

MC set to 5.1 output, playing 6 channels
1 Left
2 Right
3 Left Surround (Side)
4 Right Surround (Side)
5 Center
6 LFE

MC set to 5.1 output, playing 8 channels
1 Left
2 Right
3 Left Surround (Side) + Left Rear
4 Right Surround (Side) + Right Rear
5 Center
6 LFE

and none of these match the output when testing channels in linux audio settings.

Does it make sense that when MC output is set to 7.1, the outputs for 'Left Surround' and 'Right Surround' change depending on if 6 channels or 8 channels are playing? Is MC outputting incorrectly or is MC intentionally moving the side surrounds to the rear speakers when there is only 6 channels playing with 7.1 output?

I understand that channel order for outputs can change depending on if are using 6 channel output or 8 channel output, but it does not make sense to me that the channel order changes depending on if you are playing a 6 channel or 8 channel file.

If i make a zone with 7.1 channels and play MC 7.1 calibration audio I get this:
(The numbers are the numbered outputs on the DAC)
3 Rear Left (used in 7.1) (channel 5)
4 Rear right (used in 7.1) (channel 6)

If i make a zone with 7.1 channels and play MC 5.1 calibration audio I get this:
(The numbers are the numbered outputs on the DAC)
3 Surround Left (channel 5)
4 surround Right (channel 6)

Again, is it intentional that when playing 5.1 sound with MC set to 7.1 output that the Left Surround (Side), and Right Surround (Side) come out the rear channels?

Thanks

Just to second Hendrik's point your orders are all very unusual.  When I set MC to 7.1 I see L R C LFE LR RR SL SR, and when I set MC to 5.1 I see L R C LFE SL SR.  I haven't found a configuration that puts center at 5 or LFE at 6, but it's that way in all of your setups?  Make double sure that you aren't reordering your channels in DSP studio (i.e. one of the parametric equalizer options lets you reorder the channels)?

In either case, it's expected that with 5.1 playback the SL and SR are in the 5 and 6 position, but in 7.1 playback they're in the 7 and 8 position for the reasons Hendrik outlined.  If you're only using 6 channels, you should probably just set 5.1 as your mixing target and be done with it (i.e. I'm not sure why you'd set the output to 7.1 at all if you only have six speakers unless you're doing active crossovers or something?)

[syndromeofadown]

Thanks for the replies. I understand more now.

I'm not sure why you'd set the output to 7.1 at all if you only have six speakers unless you're doing active crossovers or something?)

Another 5.1 setup I have, I use 6 speakers plus sub. I use 8 channels, combine the rear and sides, then use one of the rear outputs for a second center channel speaker. I was thinking of keeping 8 channels to have those ports available for other tasks. I will do a separate post later, as things will get a little fancy with this setup as the dac allows for 8 channels of analog input too. This is actually easy to deal with though because the numbered input simply passes through to the same numbered output. The dac outputs single ended and balanced simultaneously so I can use my balanced amps with unbalanced sub.

Regardless of how the channels are ordered in different scenarios, there is consistency to it and it looks like I can simple set output to 5.1 or keep at 7.1 and do some channel mixing in parametric equalizer.

More info about my setup:
I did have JRSS mixing on. I see now there are options for No Upmixing, and Clone Side Channels to Rear. The latter may apply to my situation.

I am connecting to DAC via USB. For linux there is no DAC software or dsp applied in the DAC. I agree the channel order is weird. This is what led me down the path of confusion. Testing one channel at a time to see what output is what. If I had to guess, the channels are weird because the DAC is designed to be used with minidsp software on Windows and Mac. They probably reroute it in their software to make more sense. From what I have seen, their software has some similar functionality to MC DSP, which would make it redundant for someone who only uses MC. I have not used their software other than for firmware updates.

The DAC does accept earc hdmi, but only LPCM. I plan on giving this a go soon, when time permits. It will be the first time I will try using hdmi for audio. This is dangerously close to using a receiver, heaven help me. I am antireceiver, or a receiverphobe, however you want to label me, I am fine with either. minidsp documentation says there is different channel order when using hdmi, so I will see how this goes.

I will do some more tests, and hopefully be less confused. I will post again if something truly doesn't make sense, but either way I will have working audio because my setup does currently work in 5.1.