Unable to get 7.1 audio - just 5.1

[HumbleIdiot]

Running VLC 3.0.21 Vetinari on a Windows 10 Pro laptop with update 22H2 on board.
I have an AV controller connected to 7+1 speakers plugged into my HDMI port and when I right click the audio icon in the system tray I see that 7.1 speaker setup is a ticked (i.e. selected) option. If I go to the Windows Settings > Manage Sound devices page I see my "AV Preamp" and clicking the 'Test' button causes the appropriate bings to come out of all 8 speakers one by one just as it should.

I have downloaded Dolby Digital Plus 7.1 Surround Sound Test from https://youtu.be/opdkNl-cSCY?si=CI4k4WzEEdYH0uQl and that produces the anticipated sound from the left, centre, right and LFE speakers. However Surround Left as well as Surround Rear Left both come out of the rear left speaker. dido the right.

I used 4K Video Downloader (Professional License) to download the video. If I right click on the downloaded file and select Properties, Details tab, I see that the audio contains 6 channels.

Do I need a different method of downloading the video from YouTube ? Am I barking up the wrong tree ?

[Lotesdelere]

If I right click on the downloaded file and select Properties, Details tab, I see that the audio contains 6 channels.

Exactly, all of the multichannel streams on Youtube are 5.1 and not higher.

Some 7.1 test files:

WAV:
https://upload.disroot.org/r/jefZTk3G#l ... Cq+4V1BZk=

Dolby Digital Plus with Dolby Atmos from Dolby:
http://download.dolby.com/us/en/test-to ... _7_1_2.mp4
http://download.dolby.com/us/en/test-to ... _7_1_4.mp4

Various codecs and containers:
https://kodi.wiki/view/Samples
https://drive.google.com/drive/folders/ ... OS2vEX7N4b

[HumbleIdiot]

Many thanks Lotesdelere, the first link provided downloadables that proved a working 7.1 system.