Silvercn, you'll probably get more responses if you post your question in either the "Software" or "SONAR Producer and Studio" forum, since you're asking about something that's covered more in those forums than in this one. (This one is for the discussion of DirectX, MFX, CAL and Studioware.)
That said, here's a good, concise
article on linear phase EQ from
Electronic Musician magazine. In general, linear phase EQs are used in the mastering process. These EQs preserve the transients in your music as much as possible, so they don't "color" the sound.
Parametric EQ is a bit different. With a parametric EQ, you can choose the frequency, the "Q" and the level independently, and you can do some real "surgery" on bad sounds by zeroing in on specific frequencies, if necessary. JL Audio has a
brief overview of parametric EQs--complete with a few charts that actually help show what's happening.
I'm not sure what the VX64 was referring to for "compander", but a compander can be a device with a
compressor and exp
ander in it. It also can refer to a two-step noise reduction process where audio is compressed when recorded to tape, and expanded when played back. This process allows you to boost signal-to-noise ratio. There are other applications for this, but in general, it's a compression/expansion process.
I hope this helps, but if you need any more info, check out the threads I mentioned above.