I know that you can't get the functions that require a HDMI 1.4a cable with a HDMI 1.3 cable, but that's not what I'm saying... What I'm saying is that Dolby Digital 5.1 and DTS 5.1 has been supported since the introduction of HDMI 1.0, and therefore doesn't require HDMI 1.4a cables or ports to transfer the bitstream.
I've copy/pasted the functions included in the different HDMI versions from Wikipedia so you can see what I mean:
| HDMI version | 1.0 | 1.1 | 1.2 1.2a | 1.3 1.3a 1.3b 1.3b1 1.3c | 1.4 1.4a 1.4b | 2.0 |
|---|---|---|---|---|---|---|
| sRGB | Yes | Yes | Yes | Yes | Yes | Yes |
| YCbCr 4:2:2/4:4:4 | Yes | Yes | Yes | Yes | Yes | Yes |
| 8 channel LPCM, 192 kHz, 24-bit audio capability | Yes | Yes | Yes | Yes | Yes | Yes |
| Blu-ray Disc and HD DVD video and audio at full resolution[a] | Yes | Yes | Yes | Yes | Yes | Yes |
| Consumer Electronic Control (CEC)[b] | Yes | Yes | Yes | Yes | Yes | Yes |
| DVD-Audio support | No | Yes | Yes | Yes | Yes | Yes |
| Super Audio CD (DSD) support[c] | No | No | Yes | Yes | Yes | Yes |
| Deep color | No | No | No | Yes | Yes | Yes |
| xvYCC | No | No | No | Yes | Yes | Yes |
| Auto lip-sync | No | No | No | Yes | Yes | Yes |
| Dolby TrueHD bitstream capable | No | No | No | Yes | Yes | Yes |
| DTS-HD Master Audio bitstream capable | No | No | No | Yes | Yes | Yes |
| Updated list of CEC commands[d] | No | No | No | Yes | Yes | Yes |
| 3D over HDMI[147] | No | No | No | No | Yes | Yes |
| Ethernet channel | No | No | No | No | Yes | Yes |
| Audio return channel (ARC) | No | No | No | No | Yes | Yes |
| 4K resolution support at 30 fps[148] | No | No | No | No | Yes | Yes |
| 4K resolution support at 60 fps[162] | No | No | No | No | No | Yes |
| Rec. 2020 color space support[161] | No | No | No | No | No | Yes |
| YCbCr 4:2:0 support[163] | No | No | No | No | No | Yes |
| 32 channel audio support[162] | No | No | No | No | No | Yes |
| 1536 kHz audio support[162] | No | No | No | No | No | Yes |
| 4 audio streams support[162] | No | No | No | No | No | Yes |
| 2 video streams support (Dual View)[162] | No | No | No | No | No | Yes |
| 21:9 aspect ratio support[162] | No | No | No | No | No | Yes |
So why do you insist that 5.1 audio is a HDMI 1.4a and above exclusive feature, when it's simply not the case?
If the user WANTS to use the features exclusive to HDMI 1.4a, then a HDMI 1.4a cable is of course required, but that's not the case here... "x t" who started this thread asks about simple 5.1 audio, which again is supported from HDMI 1.0 and up, so therefore any HDMI cable should work... Why is that not the case with a Intel NUC?