What is an upmix?

Upmixing audio allows you to recreate a more immersive audio experience from legacy audio tracks. An upmixer creates additional channels from the original content to try and fill as many of your theater silent speakers possible.

The ISP is able to upmix legacy tracks (stereo/5.1/7.1) sources with:

Dolby Surround
DTS Neural:X
Auro-Matic

An upmixer cannot be applied on top of another immersive format.

i.e: A Dolby Atmos content cannot be upmixed by Neural:X, a DTS:X content cannot be upmixed by Auro-Matic…

An upmixer is the inverse of the stereo downmixer, which mixes all of the content down to 2 channels Left an Right, from 5.1/7.1 or even immersive content.

StormXT is not an upmixer but StormAudio own “ambiancer”. It can be added on top of an upmixer to fill in the unsupported speakers by that upmixer using the adjacent speakers.