I have seen a few posts recently about Head units with digital inputs or room/car correction.

To create one of the best sounding installs within a car enviroment I would reccomend the following is evaluated.
Ideally this would be used with the empeg digital output to eliminate any souce based noise pickup and some focal or other high end speakers and amps. At around 450 British pounds (approx 600$ ) its a absolute steal...


Alpine pxa-h700
the PXA-H700 delivers state-of-the-art vehicle sound tuning with 1/3 octave equalization, digital crossover and precise digital time alignment.

Utilizing Alpine’s exclusive MDAC 96KHZ/24 Bit multi-level digital-to-analog conversion technology co-developed with Burr Brown, the PXA-H700 delivers ultra-high quality sonic performance with precision sound tuning directly from the head unit. The PXA-H700 features 8-channel digital time correction to precisely align all speakers for maximum sound imaging; a digital equalizer that offers up to 165 bands of 1/3 octave equalization or 27 bands of parametric equalization; and an 8-channel digital crossover with variable slope adjustment and crossover points to deliver phase-shift free performance for any multiple amplifier system. In addition, the PXA-H700 features Alpine’s own Media Xpander™ sound correction technology for enhanced audio quality from compressed media formats.

http://ecominet2.alpine-usa.com/pls/admn/item_info?p_item_name=PXA-H700&p_category=160&p_subcategory=&p_main=10

Sorry, but that doesn't do it for me.

The empeg already has 4V preouts from Burr-Brown DACs.
The empeg has 20 bands of parametric eq, vs the 17 of the Alpine, with more flexible Q parameterisation.
I don't really care for 31 bands of graphical eq - if you can't do it with the parametric eq, then the speakers/crossover/amp combination just isn't working in the car to begin with.
The empeg already does L/R time alignment.

Ideally this would be used with the empeg digital output to eliminate any souce based noise pickup

How?

empeg ---D---> Alpine ---A---> amp
vs
empeg ---A---> amp

Both have the same number of analogue stages, so your supposition is based upon the Alpines outputs being significantly better than the empegs, which they are not. In addition, since the analog run is then typically long, the potential for noise pick up thus marginalises any differences between the two anyway.

What I would like to see is an amp, (or boot mountable DAC processor) that could eliminate that long run. That would be significant.


This Alpine HU could be useful for anyone adding a DVD player to their system, since it's multichannel features (separate center channel, 8 channel time alignment etc) would then be very useful. But $600 doesn't qualify as a steal otherwise. (IMO)

In reply to:

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The empeg already has 4V preouts from Burr-Brown DACs.

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Actually, that's a common misconception about the Empeg's circuitry. There are no Burr Brown DACs inside. The DAC is part of the highly integrated Philips DSP. If you think that's equivalent or superior to modern dedicated DAC ICs, then you are just plain wrong.

The Burr Brown output stages are 4 volts which is good, but there are headunits with higher voltage. Some of the Eclipse units have 8 volts and even 16 volts, making long cable runs less of an issue. Of course it would be better to put an external DAC right next to the amp and there are mobile DACs available for that purpose- some even with 8 volt outputs.

This is what i would like to do:

Eclipse headunit---D--->External DAC---A--->Amp
^
D
Empeg

Stu

*smacks self around head with large idiot stick.

You'd think that I'd remember that after reading the SAA7705H user manual cover to cover. I wonder where that misconception originated and why it seems to survive, even for people who know better.

In reply to:

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I wonder where that misconception originated and why it seems to survive, even for people who know better.

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My guess is the two Burr Brown opamps on the mainboard. Tinkerers saw them and given Burr Brown's footing in DACS, assumed they were the DACs used in the Empeg.

Stu

Sorry to disagree with you genaxia
but I think as Stu clearly pointed out , you cannot be really familiar with the internal workings of the empeg, over time technology has moved on from the quality possible by the output stage of the integrated on boeard phillips dsp DAC.
( fantastic in its time by the way respect to the Guys )

The Alpine H700 DAC is more or less external anyway ( in a hidaway box ) and the headunit is just a display and controller for the actual audio circuitry that can be mounted right next to the amps. Untill somone impliments "brute fir" and "jack" on a car platform with sufficient processing capability to generate enough digital outputs to feed to independent digital amps the alpine is more or less as close to as good as it gets right now.

Ideally the technology in the new TI class D amps like the tas5015 will make its way to the car audio market and will allow compact extreme quality amps relatively cheaply, remember Ti now own burr-brown and recently bought toccata ( the technology behind the 10k$ Tact millenium, one of the worlds best poweramps )
http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=TAS5015

But this is not with us yet and no one gives us enough digital outs (some of us are always awaiting new technology as much as a beta 3 release ) but a major benefit here is the possibility of improving the weakest links in an audio system, usually the passive filter network in the speakers and the enviromental compexities of a car enviroment, If you hear a real active digital xover enviroment correction system with FIR rather than IIR filters in the time domain i think you would be a little less dismissive of where the alpine going. Check out "RMC" on AVS forums

The item I thought some people might benefit from allows a short run of 4v line level signal cable to your amps that feed each drive unit directly without any x or c in the way this significantly improves the contol the amp can exert over the drive unit and therfore the systems response.

I'm sorry if this doesn't do it for you and you prefer to run direct from the integrated dac in the onboeard DSP chip via some op-amps, analog circuitry, phono cables, amps, speaker cables, passive filters and then finally into your drive units then fine thats your choice but I think that a lot of people on this board have spent a lot of care and attention on their in car HI Fi systems ( not many middle of the roaders have even heard of EMPEG let alone understand it or own one ) not to mention cash ( empeg alone was origionally close to 1000 US ) and therfore may want to optimise their systems as much as possible to benefit from this incredible technology ( also significantly improved capability by Maczrule's Dig out upgrade --Respect where its due ) , to those people ( who may look at focal, phase linear etc drive units and xtant or similar amps ) I dont think $600 is a lot of money.

Especially when you consider that an Alpine H700 ( based on the F1 tech ) and Empeg with .wav or ideally .flac ( beta 3 )output could then compete or better many Extreme High end ODR,EFX,XES pioneer P9 or so called reference "denon z1" & mcintosh systems etc at a fraction of the price.

All I am trying to do is point out an option for people who do care and think about these things, and hopefully help out some users on this board.....