This New Plugin Makes Dolby Atmos Upmixing Ridiculously Easy

In this video, I take a close look at UpM1xer, a brand-new multi-channel upmixing plugin from Max1mus Audio. Using a simple session in Reaper, I walk you through the full interface — from the clever profile-based workflow and multiple engine options to the per-channel gain controls, EQ, diffusion settings, and the general immersion knob. UpM1xer makes it remarkably easy to take a stereo signal and upmix it to 7.1.4, and it includes a few features I genuinely haven't seen anywhere else, like the immersive transient shaper, the LFE subharmonic generator, and an Easy mode that strips the plugin down to just three controls.

Overall, I think this is a very strong first release from Max1mus Audio. The Exact mode for ITU-compliant downmix compatibility is a standout, and it'll be interesting to see how it compares to Sam Hocking's Immersive Nulling Upmixer going forward. That said, there are a couple of things I'd like to see improved — most notably the lack of 9.1.6 support and the fact that the plugin is currently limited to Apple Silicon Macs. If you're curious, I'd highly recommend downloading the trial and hearing it for yourself in a proper immersive monitoring setup.