Do such a vst exist? I have used them in music software and they are great, but would love to widen the stereo audio in some clips. Anyone suggest such a plugin for PP or Vegas?

If the original is purely intensity stereo (i.e. recorded with one coincident pair, or mixed from multiple mono mics), the image can be widened with the following procedure.

1.) Convert from L / R to M / S (L+R / L-R).

2.) Reduce the gain on the M (L+R) channel.

3.) Convert back to L / R.

There are problems with this.

1.) If a given signal is already near the edge of the sound stage, then an out-of-phase version of that signal will appear in the opposite channel. This, of course, is bad for mono compatibility, and can easily sound bad depending on the listening situation.

2.) This technique will reduce the level of anything in the center, relative to the sides. For example if you have a typical studio music recording, where the solo vocal is dead center, this technique will reduce the level of the vocal, relative to the backing musicians.

3.) If the original recording was time (phase) related stereo (i.e. recorded with a non-coincident stereo pair) then this technique will not change the phase relationship of the final tracks, although it will change the relative levels. This could end up creating undesired phasing effects.

.Either way.. expanding an already 'stereo' recording or simulating stereo from a mono recording, I'm sure there are many VST plug-in available, both paid and freeware. But I don't have time to search for one right now though. In addition, most DAWs and audio editing software (like Sound Forge) have those kind of effects patches built in.
As Greg stated, using to excess, would do much more harm than good.

I use this one for my pro tools post rig: Brainworx | bx_solo (http://www.brainworx-music.de/en/plugins/bx_solo)

If the original is purely intensity stereo (i.e. recorded with one coincident pair, or mixed from multiple mono mics), the image can be widened with the following procedure.

1.) Convert from L / R to M / S (L+R / L-R).

2.) Reduce the gain on the M (L+R) channel.

3.) Convert back to L / R.

There are problems with this.

1.) If a given signal is already near the edge of the sound stage, then an out-of-phase version of that signal will appear in the opposite channel. This, of course, is bad for mono compatibility, and can easily sound bad depending on the listening situation.

2.) This technique will reduce the level of anything in the center, relative to the sides. For example if you have a typical studio music recording, where the solo vocal is dead center, this technique will reduce the level of the vocal, relative to the backing musicians.

3.) If the original recording was time (phase) related stereo (i.e. recorded with a non-coincident stereo pair) then this technique will not change the phase relationship of the final tracks, although it will change the relative levels. This could end up creating undesired phasing effects.

How do I proceed in Prem Pro CS5.5??

Found this on the web, have not used it: KVR: Mildon Studios releases SLVR Spreader - VST Stereo Expander Plugin for Windows (http://www.kvraudio.com/news/mildon-studios-releases-slvr-spreader---vst-stereo-expander-plugin-for-windows-19028)

Do such a vst exist? I have used them in music software and they are great, but would love to widen the stereo audio in some clips. Anyone suggest such a plugin for PP or Vegas?

Yes. Do a Google search for Nick Whitehurst's "C-Plugs". Its a samall suite of VST plugs. They all work well in Vegas. His C_Super Stereo plug is very useful. Input width and rotation, DC filter, L, R and C 3 way balance. Bass adjust, freq, boost and width. Output rotation and width.. Mono and bypass switches. Full stereo correlation meter with phase difference scale. Also has output gain controls.

Old but very good, fixed numerous out of phase audio and stereo issues for me. Never found anything quitle like them. Also a good little freq analyzer is included in the set. Llet us know how you go.