I am wondering how people turn a Quad lp into 5.1 mix? Where do the subwoofer and center channel come from....I have just learned how to get the DTS layer off my DVD-A to create a disc that will play in my car when I get that sony car player....
Creating a centre channel is easy enough in itself, there are several ways to do this.
1 - Gerzon LRC VST Plugin
2 - Farina MLRC VST Plugin
3 - Multisonic LRC VST Plugin
4 - Ambisonic tools
5 - MS type tools
The question really is "should you do this?" Only you can decide. The Quad mixes were created for 4 channels, using a Phantom Centre, and adding a dedicated centre channel will sometimes work, but more often than not it will not. It is worth a try though.
LFE.
Unless you really know what you are doing this for - Don't.
The LFE channel is a Low Frequency Effects channel, hence the name. It is *not* the same thing as a subwoofer, and (Knowing full well this will start a heated debate) generally creation of these is for movies only - not music.
This is a generalization though, and the problem you are going to face is very complicated - it's twofold in nature.
1 - You cannot ever know what the crossover points are in consumer sub/satellite setups.
2 - The Quad mixes are designed as 4 channel, full-range. When you generate your spurious LFE, are you going to subtract from the full range L,R,Ls,Rs channels (In which case you are making a disc that is only any good for you and you alone, and will never play back correctly on a properly set up & calibrated Quad system, or a properly set up & calibrated Surround setup) or are you going to add to the 4 channel full-range, in which case you will be doubling up on the original bass content, and when your system Bass Management kicks in you will almost certainly end up with severe phase issues. These will double or halve the desired levels.
At the end of the day, it is your call.
But be aware you will never be able to trade these discs as the sound will be utterly different to what you hear on your setup.