Tom Wells said:
The stereomaxx works by cancelling common-mode ( in both channels ) audio.
It can be a fine but subtle improvement.
It can be useful to remove crosstalk from previous dubbing.
It can "open up" a dead soundstage.
Use a light hand with all common-mode cancelling processors.
It may be more useful in production and dubbing work than broadcast, as source material varies considerably.
Tom:
According to the Stereomaxx manual, the device does not affect common mode (mono) material at all, but rather, adds a user-defined amount of delayed L-R back into the mix. They claim the L+R is passed with no change whatsoever and their schematic backs this up.
I'm not sure how one might use this to reduce the crosstalk from previous dubbing... And I would not say that "it can open up a dead soundstage," but rather that it creates one where it did not exist before. In other words, it's simply a form of program-controlled artificial reverb on the L-R signal.
As for using it, you have control over the length of the delay ("Depth") and the amount added ("Width"). The delay time will adjust the sense of size of space, and 'depth' is a good name for that. The amount of injection will indeed increase the apparent 'width' of the stereo stage.
Varying the 'Depth' control will have a relatively small amount of effect on the level of multipath interference created; this can be adjusted to taste... overuse of the'Width' control, however, is where you can get into serious trouble!
Again, I stress that by creating and adding a new, artificial signal by delaying and re-injecting the L-R, you are cluttering up the subcarrier region unnecessarily. If there were no multipath issues with FM, I might say go ahead and use it if you must, but since that is rarely the case...
BTW, the manual says the Stereomaxx uses Jensen transformers. Cool. If you throw it away, be sure to save the transformers.
David P. Reaves, III
TransLanTech Sound, LLC
Home of the Award-Winning "Ariane" Audio Levelers.