UM225 / UM226: Stereo-to-Surround Upmixer by Waves

Upmixing is mostly a question of how much of the signal moves into the surround speakers and how wide the result feels. The UM225 and UM226 handle this with eight modes that spread different kinds of program material to the L/R and L/R surround speakers, so you can match the mode to the source.

Ambience controls make the surround stage smaller or larger, which helps when a mix needs to stay close to the front or open up around the listener. Punch controls place transients between the left, right and center channels, which keeps percussive hits focused where you want them.

A global upmix control balances the stereo and surround versions of the mix against each other.

UM226 adds an LFE path for 5.1 work. It includes a 4th-order low frequency filter for the LFE speaker and a LoAir function that adds an octave-lower harmonic, which can be used to add rumble or sub-heavy effects.

Output trims for the L/R, center, L/R surround and, on UM226, LFE stages let you set the level of each speaker group. An energy display shows how sound is spread across the surround field, so you can see the balance as you adjust the settings.

For stereo-only remixing, the plugin can widen the image and control lows and punch without moving to a full surround layout.