I must add a review to point out that this plug-in has more uses than at first meets the eye.
You may use it to construct a Dolby ProLogic (r) encoder so that your stereo material is compatible with all the Hi-Fi amps, televisions, game consoles that provide surround sound from a two channel delivery format.
The specifications for all modern surround formats have this in common; that they extract the surround channels from the out-of-phase "S" component of the stereo stream.
The surround L and surround R signals.
The encoding process is the same for all Dolby 2 channel systems, whereas the decoders built into Dolby certified equipment varies in complexity and channel count.
To encode Dolby compatible material, you need to set up a stereo AUX bus with the Voxengo Phase plugin, apply a short delay to both channels and a +90 degrees phase shift to the L channel and a -90 degree phase shift to the R channel.
All channels you want to have appear in your rear speakers will have to have in addition to going to the main stereo bus, a send to the AUX channel. The send should have a pan pot so you can send the signal to either channel of the Aux bus.
When you increase the level of the send, you'll hear that the sound moves from front to back in accordance with your send level. The panning of the send will determine if the sound emirates from the left or right surround speakers. The mix between the send and the main stereo content will determine the fromt/back placement.
For a description of the levels and specifications, see this link: https://en.wikipedia.org/wiki/Matrix_decoder#Dolby_Stereo_and_Dolby_Surround_.28matrix_4:2:4.29
This plug-in is the only one (and I've tested a lot!) that actually offers a true 90 degrees phase shift across the frequency range and that works as a surround encoder. The quality of the sound is pristine, and I'm happy to have found this gem!
In a market bloated with 'emulations' of classic gear, it's rare to find juicy sounding plugins that capture the best qualities of 'classic', offer some flexibility and don't break the bank. In the universe of more tweakable plugins, here too only a few offerings stand out.
After years of working with hundreds of plugins from numerous companies, I've found only a handful of offerings that keep me coming back. One of those companies that still hold a top spot is Voxengo. Their plugins are 'analog' without being slavishly limited to a given hardware model; flexible but not overloaded with 'feature bloat'; affordable without sacrificing sound quality; and have excellent & consistent GUIs to work with. A winning combination.
There is definitely a place for well designed emulations of classic gear, but when you require some flexibility and/or modernity, Voxengo is great choice. Their uniform GUIs also promote actually listening to the music!
Voxengo also has an easy robust activation system (no dongles), exceptional reliability (I've never had a Voxengo plugin crash my DAW in 14 years) and full 64 bit floating point processing*.
It's pretty simple why Voxengo plugins are so good - Alexsey has a better ear compared to other developers.
His plugins sound so 'musical'. I've used many other plugins that technically perform their designed function, yet somehow just don't sound good.
I now have a whole set of expensive plugins that are just taking up drive space. They simply don't sound as good as thier Voxengo counterparts.