Enough other people have asked that Google offered "does HDMI have audio" for it to be a ready-to-go alternative search selection, which gave me this
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"Many new HD-DVD and Blu-ray players have built-in decoders that will output the new multi-channel audio formats over HDMI as 8 channels of linear PCM 192 kHz/24-bit uncompressed digital audio, so if your AV receiver or AV preamp will handle a multi-channel PCM signal and is HDMI-compliant, then you'll be fine.
10.1 Things You Should Know About HDMI - Axiom Audio
http://www.axiomaudio.com › hdmi
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Immediately before this, a search result snippet informed me that HDMI carries as much as 8-tracks of audio but it is PCM encoded, hence the products describing themselves as able to 'split out' the audio.
I know nothing about this Maiz box and will read up about them separately.