Streaming media rippers don't really need a voice activation system. If you have a good internet connection to the media server there is a very little chance that you won't be able to record stream from Windows Media Player.

Many stream rippers can even use multiple threads when downloading an on-demand stream to fully use your bandwidth (so you may download media streams faster than in real time). Obviously one can't use multiple threads when downloading a live stream.

IMHO it is always better to try stream ripper before using direct sound recording software like ScanRec. WM Recorder is the best software to download streaming content from Windows Media Player. No other Streaming media ripper can compete with it. And it is not only very powerful, but also very easy to use.

Besides it can record not only Windows Media streams, but also Real Audio/Real Video, QuickTime and Flash streaming video.

And stream rippers don't record silence. They whether record a stream or not. It could be a problem due to a network congestion especially for live streams. And with WM Recorder can even record live streams in case of a bad connection and remove silence gaps after recording.