Okay one last question only talking sound quality here everyone already knows the Empeg Interface Rocks

What would sound the best. Assuming the amps line levels and speakers are all the same and there all installed in the same car

Empeg Playing 320Bps Mp3's or Waves
P4 XXX with win amp and a Good SB car (zx or zx platinum)
Alpine Deck playing Mp3's or waves from cd or DVD audio ?

Which would sound the best and please explain your answers

The empeg and the alpine deck would most likely sound equally good.

The PC would sound inferior because the output stage of most consumer-level sound cards isn't as good in terms of noise floor and frequency response. Plus, in-car computer installations where you jerry-rig a desktop PC into a DC/car environment are going to be tricky to get right in terms of noise rejection.

Of course, with the alpine deck, you'd have to swap discs, you wouldn't get all the music organization features of the empeg, etc.

I would add that the empeg has 4v outputs instead of 1v typically found in most car audio. This gives a bit more signal range when paired with an amp that expects 4v inputs.

Most current car audio decks are 4v, if I recall correctly based on my skims through the Crutchfield catalog each month.

320kps mp3s will fill up blank CDs pretty quick... Also, CD-Rs are more likely to get scratched. I could go on and on about how great the empeg's menus are compared to any mp3/CD deck out there, but I know you were asking about sound quality, not features.

The empeg has really nice Burr-Brown DA converters and a VERY nice parametric EQ.

Most aftermarket decks, with the exception of high end ones, distort as the volume reaches past 80% maximum volume, even when using RCA outputs. Because of this, an osciliscope is often needed to determine at what point the headunit begins to clip its signal. The empeg (and some very high end decks) do not distort as the volume reaches maximum output. It only clips the signal when you pass 0.0dB, but that is easy to disable. This another area when the empeg shines.

Other empeg sound features (with HiJack):
Automatic Volume Adjustment (Off, Low, Medium, High)
Left/Right Time Alignment (This feature kicks butt.)

And just to clarify, the DSP in question is a commercial one intended for use in car CD players, so the empeg is essentially using the same kind of output circuitry as that alpine deck would use, so it would sound more or less exactly the same.

It depends on whether the Alpine has a newer generation DSP. Although the empeg was designed with top end components, it has been several years now and they must have done some improvements since then. No idea if you'd be able to hear that difference.

What are opamps?

This just ruins the introduction of what I'm working on!

Ah. okay. That makes sense. I did a Google on opamp and it seemed they had a ton of uses.

I don't know why, but "Burr-Brown" has stuck in my head since I was in the Mk1 queue. I think I had a Sony MD player that advertised its BurrBrown DA convertors and I saw a reference to BurrBrown in some of the WAY old empeg advertising. I must have assumed that it was also for the D/A process.

The rio-car used burr-brown op-amps in the 4v line out stage, too.

TI bought them a couple of years ago, and by some accounts they've gone downhill since then. Certainly the great apps guy who used to work for BB in the UK is no longer with them.

Hugo