A digital signal turns analog at some point, even if it stays wholly digital until the amplifier stage. But I don't think that's what you meant by your post. Are you talking about active vs passive crossovers, records versus cds/flacs, etc?

 

A digital signal turns analog at some point, even if it stays wholly digital until the amplifier stage.

This.

My dream system consists of (almost) all digital:
* BMW headunit (MOST optical output)
into
* mObridge DA3 (MOST input / Toslink optical output)
into
* Brax DSP (Toslink input/output)
into
* Brax MX Series amplifiers (Toslink inputs)
into
* Focal Utopia M Series speakers (Analog)

In reality, this amounts to little more than 'coolness factor', because the noise floor of a vehicle will be far higher than the noise floor difference between D/A conversion.

Pure analog is the way to go, if you're wanting thest sound quality. But, totally impractical in a car audio environment.
Phonograph, into tube amp, into speakers.

 

He's got to mean active vs passive crossovers since nothing else makes much sense. He could be talking about tapes vs other digital media, but I seriously doubt it.

 

I am referring to an all optical system vs all analogue system.


Ex1: Media player > headunit via optical > headunit to dac/amp via optical cable.

Ex2: Media player > headunit via aux cable> headunit to amp via RCA cable.

 

It's impossible to say which is better. Too many variables. It's going to come down to the quality of the components used in each example and your own opinion.

 

Keeping the signal chain digital for as long as possible, or rather avoiding unnecessary Digital => Analog => Digital => Analog conversions will increase the quality of your signal, sometimes by a large margin. It just depends on how strong or weak the other components of your signal chain are.

But keep in mind that you really need to think of this in relation to the other parts of your build. Crappy SNR cheap-o amplifiers? You probably don't need to fret as much about your signal chain. Starting off with high-level inputs from your stock head-unit? It's probably already screwed, so being cautious from that point forward won't really do a lot for you.

If, on the other hand, you have something like this:

Quality Digital Player => Coax/I2s/Toslink => DSP (digital) => High-end DAC [Sabre ES9038, Dual AKM4499 chips, etc] (digital input / analog output) => Balanced outputs to Amplification

Then yes, an unnecessary Digital to Analog conversion will affect your system. The ability and accuracy of your setup will also matter of course.

Basically, the point I'm making is that being extra, extra mindful of your signal chain becomes important when the rest of your install is good enough to have that part become the weakest link.

 

An all analogue phonograph has a pretty low noise floor.
And most D2A and A2D conversions are well below the noise floor of the vehichle.

 

It seems like a large waste to go digital, when ironically almost all dscs/dsps output analogue anyway. The only true digital system I've seen is a carrozzera optical headunit to a R-7x/9x, where the dac and amp are in the same unit. Crazy to think the retail price in 2004 was around 8k combined.

 

The JL VX amps have a dac/amp and dsp built in and only do digital.

 

The VXi amps have both digital and analog inputs and outputs. How much conversion goes on depends on how you use it, but it still has to convert to analog for the amplifier section.

I think this is one of those situations where, at some point, you're looking at diminishing returns. You want the best signal to noise ratio possible, but at what point do human beings stop being able to hear a difference?

My own setup consists of a Honda factory HU, a FiX-86 and a VX800/8i. It is dead silent when tested with a zero bit test track. I hear nothing between tracks, and then (on some songs) I can hear when a track begins playing by the sound of the room noise captured in the recording itself. Given the components in my system, I know there are several points where the signal is converted from analog-to-digital and digital-to-analog, but I'm still happy with it.

So I guess the point of my post is that it doesn't have to be perfect, just good enough. How many times it does a DA or AD conversion is not as important as how well it's done.

 

I noticed a big difference by going optical into the processor from a pure i20. I had a head unit feeding the processor before and I think too many conversions were taking place. I could tell especially when the ipod was connected. I did not change any equipment and the difference was pretty drastic. Also the noise floor when running optical is great. I would choose one optical plug over 8 sets of expensive rca's any day.