In Windows surround speaker setting, never use 5.1

[xrqp]

If you use Windows to play media, NEVER choose "5.1 Surround". If your speaker system is 5.1, or 5.x, or 3.x, instead use "7.1 Surround".

Windows’ 5.1 channel mask setting is ambiguous and can sometimes result in channel mapping errors.
In Windows 10 and later, it was superseded by the 7.1 setting to fix the issues, and the 7.1 setting works well with 3.x and 5.x systems. Unused channels stay silent.

Ai told me this, but I grilled it for hours on its sources to be sure. Microsoft does not state this directly, the way I did. But they say 5.1 has channel ambiguity issues. And they do not say it about 7.1. If you have experience for our against this statement, please share.

 

[phoenixdogfan]

I have been using 5.1 all along in conjunction with JRiver and everything maps as it should. You have a test capability. Just click on each speaker and listen to which speaker plays. I don't use 7.1 because I have no true native 7,1 sources and I do not want either Windows or JRiver creating the extra two channels and sending the surround information to two channels have no speakers for. I am not sure what specific ambiguity issues, the 5.1 setting creates.

 

[kyuu]

Ai told me this, but I grilled it for hours on its sources to be sure.

It doesn't matter how long you "grill" a chatbot, that still doesn't make its output trustworthy. Please share if you have an actual source for this, otherwise I feel comfortable classing this as a nothingburger. I've used the 5.1 output in Windows and have never noticed any channel mapping errors.

 

[xrqp]

Yes, I should have given the source. Here is one source:
Mapping Stream Formats to Speaker Configurations - Windows drivers | Microsoft Learn
It is long. One example paragraph is
"In earlier versions of Windows (Windows Server 2003, Windows XP with SP1, Windows 2000, and Windows Me/98), the interpretation of the channel mask 0x3F is that it assigns the six channels in the 5.1 format to the following speaker positions: FL, FR, FC, LFE, BL, and BR. (This is the back-speaker 5.1 configuration.) However, the interpretation in Windows Vista, Windows Server 2003 with SP1, and Windows XP with SP2 is different: by convention, the 5.1 format with the channel mask 0x3F is interpreted to mean the side-speaker 5.1 configuration instead of the back-speaker 5.1 configuration."

 

[kyuu]

I read the article. I do not see anything that suggests there is an issue with channel mapping in the 5.1 configuration.

 

[xrqp]

Quotes from the source link:
“In fact, the channel mask for the 5.1 stream is 0x3F rather than 0x60F…”
So the Windows system mixer always sets the stream’s channel mask to 0x3F (side)… even if it receives a 5.1-channel input stream with a channel mask of 0x60F (rear).
“…it does require hardware vendors to remember to interpret the 0x3F channel mask to mean that channels 5 and 6 are assigned to the SL and SR speaker positions”. It is not enforced.

If driver vendor does remember, the driver will work right, but the driver is not the only thing in the audio chain. The ambiguity still exists system wide, and in the media. So apps, other drivers, and the media, can handle the channels incorrectly. With 7.1 this is all solved.

 

[xrqp]

It took hours of wrangling, but I got the Ai to admit this:
"For people who play 5.1 audio on a Windows PC, the ambiguity in Windows’ 5.1 channel mask can cause problems — but in the overwhelming majority of real‑world cases, very likely 99% or more, users never notice an issue because nearly all modern media, apps, and drivers treat 5.1 as side surrounds (SL/SR)."

It said 5.1 media since about 2000 uses side (not rear) channels, so less problems.

F me. This Ai is so defensive. It took me two days to get to a practical nothing burger. My apologies. Thank you kyuu.

But I will still use 7.1 and not worry about 2 rear channels of silence that are not connected to anything.

 

[flexy123]

I have two (2) "5.1 settings" in Windows, one with "RL" and "RR" (rear speakers) and one with "SL" and "SR", confusingly referred to as Side Left, Side Right. The image in the Windows settings also shows the SL and SR speakers "on the side". Since everywhere else surrounds are referred to as "SLA" and "SRA" (Surround Left, Surround Right), my hunch was right this is the correct one to select.

 

[xrqp]

Yes. Use the 5.1 side. Or you can use the 7.1 which works with 7.1, and 5.1 side, and 5.1 rear.

The 5.1 rear is only for legacy and special cases. The main article referenced was written before the 5.1 side was was offered, so it made 5.1 sound ambiguous. But with the 5.1 side option it is no longer ambiguous. I should have titled this as "Don't use 5.1 rear".

 

[somebodyelse]

It took hours of wrangling, but I got the Ai to admit this:
"For people who play 5.1 audio on a Windows PC, the ambiguity in Windows’ 5.1 channel mask can cause problems — but in the overwhelming majority of real‑world cases, very likely 99% or more, users never notice an issue because nearly all modern media, apps, and drivers treat 5.1 as side surrounds (SL/SR)."

It said 5.1 media since about 2000 uses side (not rear) channels, so less problems.

F me. This Ai is so defensive. It took me two days to get to a practical nothing burger. My apologies. Thank you kyuu.

But I will still use 7.1 and not worry about 2 rear channels of silence that are not connected to anything.

I refer you back to post #3 - this answer is no more or less trustworthy than the previous ones. If the answer is important you still need to fact check it - it could just be telling you what it 'thinks' you want to hear. If you ask for sources then check that they are real, and actually say what it claims. Plenty of lawyers using AI to help write briefs have been sanctioned when the judge or opposition checked the precedents they cited and found they don't exist, or say something completely different.

 

[xrqp]

Yes. I wish I could delete this whole thread. The last AI quote was to show that Ai completely back tracked on what it said, so it cannot be trusted. Also the microsoft.learn link (the main source) cannot be trusted because it is outdated by the "5.1 side" option that came after that was written.