Any sound engineers out there?

[Elgin Clock]

As far as a good converter from MPEG-4 to mp3 I use dBpoweramp Music Converter (dMC) for all my audio converting needs nowadays. It's great, but may require some additional codecs depending on what type of format you want to convert from. Not a big deal usually, just a few seconds to DL a new codec into it when it needs it.

http://www.dbpoweramp.com/dmc.htm

As far as canceling the lyrical portion of a song out for karaoke purposes, I'm actually spoiled as my stereo does that with the touch of a button (although I've never used that feature), so I'm not sure how to do that part.

Hope this helps!