I'm not sure if this is already a feature or not, but I would like to have temporary partial mute when giving commands.  I recently ordered the mxl USB conference mic, and I anticipate some issues with too much audio input from the speakers when playing music.  I consider music selection and browsing to be one of the many great uses for VC, and want the experience to work well.  I already have mine set to partially disable the mic when at idle for 10 seconds.  I'd like the volume to be partially muted after I turn back on the mic (using my listen phrase) for that ~5-10 seconds. 
     Of course, this would be an issue when selecting a song to play.  So, in addition, also having the ability for VC to automatically partially unmute once a 'play' action is taken would be nice.   This all may be possible with parameters, but I don't know how to define time settings, for example, partially mute for 10 seconds.

This work in version Voxcommando 0.871, import this file for your Active command tree.

A partial mute function exists for system volume, xbmc, mediamonkey and itunes.

There isn't currently a timer function that would suit your needs (unless you use eventGhost).  There is a vc.pause action that you can put into your macros but it is only to be used for short pauses since it essentially freezes the program.

I'm working on a event system of sorts that would allow this, since switching to standby would generate an event and this could be used to unmute.

If you are switching to standby with a voice command (e.g. saying  "stop listening")  then you can add unmute to the macro for the standby command.

I have been able to get this to work by using event ghost.  However, with the commands I need to send with my listen phrase (enable and disable groups with an eg broadcast) it doesn't set the idle timer.  I am forced to send back a standby broadcast from EG.  That can be a problem if I am giving multiple commands, it will only listen for 7 seconds from the initial listen phrase regardless of the true idle time. 

I think you will find this possible and pretty easy to do when I release the next version.  It is taking me a bit longer to release this than I would like because I am trying to figure out how to use validation so that I can create a demo version that only performs a limited number of commands (done) but have paid users be able to "unlock" it.  But I am having great success so far with events so you can expect to see them in the next version for sure.