33 replies to this topic

[Sonic Nirvana]

This is related to Mr_Bob's thread on the PXA-H701 and, in a roundabout way, how best to supply a digital signal to it:
I'd like to see a discussion on the relative merits as well as what is actually about to get the job done

The job we have is this:
Head unit with comprehensive eq and active crossover with maximum SQ.

Near as I can tell , there is no such animal as a single-box solution.
HUs such as Alpine 7998 and Clarion HX-D2 come close but as they say in the classics "no cigar"......

In an ideal world we have a high quality transport in a head unit, that feeds digital output to a processor that does third-octave eq etc and crossover management, time alignment in the digital domain and then has a high quality (24 bit Burr-Brown for example) conversion to an analogue signal that goes out the rca's to the power amps.
And we're sweet

First alternative method is a high quality HU with the 24 bit Burr-Brown or similar where the analogue signal goes out the rcas to a digital processor which does the eq in the digital domain by converting first from analogue to digital and then back to analogue. Lots of analogue/digital conversions going on here..... Plenty of these gadgets about, Audio Control, Orion etc etc

Subset of this: this processor also does the active crossover stuff. An example here being the Audio Control DXS and for that matter the Alpine PXA-H701 where it is presented with an analogue signal from a HU.

Second alternative method is to take the analogue signal again and simply process it in analogue stages, first through eq (bucketloads of analogue eq's out there) and then through active analogue crossover (again quite a few, not so many good ones imo).

I guess only the "SQ tragics" and I admit myself to this club here will have persevered this far. So what ya got on the subject guys, let's wring it out!
audioquest, golf_bht, shiny_car etc, you're on notice! LOL

Note: the Pioneer P9 combo looks the nicest all-digital bet I've seen but $5k?
Umm, that'll do for now, I'll go further with it later......

[-DJ-]

cyberpunky has an all-digital setup with an orion deq30 as his eq. it works O.K. :hehe:

its all very well and great to have all digital to the final moment, but really, you must ask yourself if you "NEED" all this processing...

if i was to do it my way, i'd have my transport run digitally into a rane rpm26z and have its versatile i/o port do my volume control duties.... mmmmm

d

[Sonic Nirvana]

I am a great believer in keeping things simple, and given my choice, I would keep it all in the digital domain, rather than D/A-> A/D -> D/A.

Of course there is always the school that says that analogue > digital (since we listen in the analogue "domain") and once it leaves the HU, the signal is best dealt with as an analogue signal.

Of course digital allows storing of presets which is very useful......

[shiny_car]

a processor like the alpine PXA-H701 is very much 'good enough' for incar processing. it's a very powerful tuning tool, and offers more than acceptable SQ. there's no doubt better 'DACs' out there, but few are so readily 'off the shelf' and most that are worthy of consideration are probably DAC-only, without the processing. so the PXA stands out as top value.

then team that with a suitably matching HU, and you have an awesome combination. as tunable as the pioneer P9 combo, but far better value IMO. so you'd want an alpine HU with digital output. these are fairly common enough, either secondhand or new.

i personally don't believe you need an alpine F1 7990 to produce an awesome SQ setup, and that the more affordable (!) garden-variety alpine digital output HUs more than suffice. the likes of the 7998 and older 7969, 7949, 7939, etc, all offer digital outputs and are high quality SQ units, all worth considering as your 'CD transport'. (and money saved can go towards more important things.)

for someone like Mr_Bob, changing HUs for the sake of optimising signal delivery to a PXA is a costly proposal. is it worth it? maybe, maybe not, depending on whether you can hear the results. and i think other factors would have far greater SQ-influence than a digital vs analogue output HU to match with the processor.

so i think an alpine PXA + digital output HU make a top value combo, without the need for a 7990, and a PXA with an alpine analogue hook-up would be more than acceptable.

to go all-analogue is somewhat clumsy and complex in terms of wiring/cabling. so even the practical side of things (fitting it all in!) is a big negative. i'd probably avoid it if you're looking at 31-band EQ and active xover. given the option, the simplicity of an all-in-one (digital) processor is superior, especially with the ability to 'tune from the seat' rather than making adjustment in the boot then returning to the seat.

whilst i personally would love a nice PXA-H701 to do all my processing, i've ended up with a mixture of things in my own car, and it seems to work well-enough. beyond my processor, the signal feeds through an analogue active xover and onto the amps, which also rely on their inbuilt analogue active xovers. yes, it's clumsy and relies on many connections and components, but it doesn't detract from SQ to the point of being noticably poor. so in a way, i don't buy too much into the 'signal degradation' argument if the components are of high enough quality.

[Sonic Nirvana]

Ahhh, the voice of reason

Pity we don't get the opportunity of trying competing systems before we fork out the cash ie you never find out if something actually makes a worthwhile difference IN YOUR SYSTEM until you instal it and tune it, and no-one's lending you a P9 for a couple months LOL.

Even a "modest" *cough* 7998-H701 combo is gonna set you back $3k.
If you compare the sonic performance with say a "lowly" 9827 with a H701 for $1100 less, how much less is it really? Dunno unless you actually try it.......but how?
I mean, a lot of 7998 functions are superceded by the H701, there is really only the digital- out of consequence and finding out if there is actually a difference in the DACs, well......

I expect elsewhere in the system more return can be had for that $1100.
But then, rubbish in, rubbish out, you only reproduce a signal as good as comes out of the HU.

[shiny_car]

Critter said:

Even a "modest" *cough* 7998-H701 combo is gonna set you back $3k.
If you compare the sonic performance with say a "lowly" 9827 with a H701 for $1100 less, how much less is it really? Dunno unless you actually try it.......but how?

yes, the $60 million question; won't know until you try, and even then, probably only an ABX test would demo any difference...and that's hardly a practical/feasible proposition.

Quote

a lot of 7998 functions are superceded by the H701, there is really only the digital- out of consequence and finding out if there is actually a difference in the DACs, well......

hook up a processer, and the likes of the 7998 lose all its tuning functions in favour of the processor. that is, the processor becomes the default tuning device. so indeed it's an expensive outlay for merely a 'CD transport'.

i guess that's why Mr_Bob and golf were discussing the use of a CD stacker with digital output. this could simply hook straight up to the processor, and from a functional point of view, be fully controlled from his existing HU. the outlay is far less (eg: ~$600 for an 'as-new' CHA-624) and worth considering IF digital output is the priority here. the quality of the transport is of course another issue which we won't buy into here (although IMO, they're perfectly fine).

Quote

I expect elsewhere in the system more return can be had for that $1100.
But then, rubbish in, rubbish out, you only reproduce a signal as good as comes out of the HU.

that you can spend the money elsewhere is a vital point being made . unless you can afford it all, then a compromise is likely required. it may be acceptable to do one upgrade step at a time and get a new HU later, but surely accepting an analogue signal transfer from HU to processer (via the Ai-NET cable) and having another $1K to spend elsewhere is a good thing. $1K will buy or go towards new speakers, sub, amp, whatever, which i expect would yield more benefits than an improved signal transfer!

[-DJ-]

Critter said:

rubbish in, rubbish out, you only reproduce a signal as good as comes out of the HU.

lol critter... just about to say that myself. garbage in garbage out. it all starts with your source so you should make it a good one. i feel ANY extra gains you can have here are worthy additions if your pocket can wear it!

d

[Sonic Nirvana]

The trouble we all have in this car audio business, and I feel this very acutely coming from home hi-end hi-fi is the lack of opportunity to compare before you buy.

In the domestic hi-end sphere you have opportunity to take home a new CD player, amp, whatever, and try it in your system, and other products of the same type, and decide if/what does it for you in your system......in advance of shelling out the cash.

We can't do this practically in car audio, we can only go through it systematically from "first principles" eg rubbish in, rubbish out.....or less A/D or D/A conversions = better.......and it is but how significant is it?

Spend big $$ to find out, mostly.

I spend too much time, SQ tragic that I confess to being, pulling things out of the car and substituting things almost any time I can to develop a storehouse of experience with different things. No substitute for it.

Just at the moment I have the JL amp that feeds the front stage out and a Tru T-2.200v2 "visiting" the Morels to "see how they get along"
Short version, early times yet though.......ooh that Tru is clean......

[dazdillinger]

keep in mind many "audiophiles" believe, and that a couple of tests have demonstrated that in fact the transport plays a bigger role in changing the sound than the DAC
just an interesting thought that id read about be4

[Sonic Nirvana]

Oh yeah.
Again from first principles, the transport comes first in the whole chain of events.

And again from our trying to establish other than by paying for it, how do I know whose got the good transports.....?

Putting a fancy name on it doessn't make it a practically better thing, for instance.

Be nice to hook up to that kind of imformation.

[blue_6006]

After experiencing a digital front end in my current Sony ES system, I think I will find it hard to go back.

Using the CDX-C90 as a transport, it is connected to the XDP-4000X via fibre optics, the HU controls the XDP via a unilink cable.
The XDP has either a single or dual 24bit DAC, it then outputs this signal via 8V preouts.
Being fibre optic, no noise can enter the signal on the way to the XDP.
The thing I like the most is that I only have to use 1m interconnects from the XDP to the amp, this once again ensures minimal signal loss.

If you ask any audiophile in home audio, they will tell you that if you are after pure SQ you will use an external DAC with a kick ass transport.
A good example of this is Cyrus, they make a transport and DAC, the DAC itself is as big as the transport. With an external DAC, there is more room to put in better/more components also there is no interferance from the transport.

If I ever have to replace my ES system (I dread the day) it will be with something that has an external DAC. Or if I can another ES or XES system. That is unless something better can be had for the same money, which I am yet to find.

[dazdillinger]

also i know the situation you proposed may have been a hypothetical, keep in mind any changes that may be caused by a better transport and DAC probably wouldnt be noticeable in the car anyways so it comes back to the point of "is it all worth it?"
if ur made of money i guess it is...

[golf_bht]

Hey Shiny I think the DA in H701 will dramatically improve your system dramatically due to S/N charactors of the unit due to components being used compare to your processor. If you can pickup a H 700 for a cheaper price then go for it. H701 only have a revised program so that their new HU can control it directly.

[shiny_car]

nah, i've spent enough $$ on car audio. i'm simply going to continue working with what i already have.

[bodapa]

Ah, at the end of the day, after all tom dick and harry have gone to sleep including their cats and dogs and neighbours and God knows what else, it's the folding stuff that matters... that is why discussions like this spring up on various forums all over the internet 24/7.

So how do you justify whether a processor (or a HU or speaker or whatever) is worth buying? It all comes down to benefits over price, which is the perceived customer value. Do you perceive that the benefits are high enough (in terms of features, built quality, etc.) and differentiated enough that price becomes somewhat irrelevant? Or do you feel that the low sticker price is attractive enough that features come second? To what extend are you willing to spend on audio components? How do you feel about your hobby? Is it something that you take seriously or not? And if you are, to what extend do you want to take it further? What are your priorities in life? And lastly, do you have the financial power to commit to that purchase?

Apologies for going off-track here, but until these questions here are honestly answered, a lot of people would have difficulties justifying if a HU or processor is worth buying. When I bought my HX-D2, I went through all of that, evaluating things that weren't remotely connected to car audio at all...and in the end, to me, it was worth the sticker price. And the process just keeps repeating itself everytime I see something attractive...

Getting back on track, I personally had the opportunity to use the 7998R and the H700 and the CHA-S624 changer with the digital output. Since both the HU and the changer have toslink digi-out, I did an informal test using a 4m Monster cable Interlink optical cable, swapping between the 7998 and the 624. For some reason, it seemed that the 624 changer sonically performed better than the 7998 using digital out, even though the difference was very slight. Maybe because the 624 has MDAC in it, and to support that it needs a great laser and lens mechanism that can read CDs better than the 7998...I dunno...

I also tried using the standard AI-net connection (the audio portion) from 7998 to H700 and used digi out from 624 to H700. Played the same track, using the same volume setting, and the sonic differences were more pronounced (the 624 was cleaner, and "still", for a lack of a better word).

So yes, it was worth it for me to try it out, and I learned something from it. My advice: those of you who have the S624 changer, hold on to it! Get yourself a H700 (or a H701) and feel free to buy the cheapest Alpine AI-Net deck you can buy, new or 2nd hand (a cassette deck is sufficient, as long as its got AI-Net) for you're only going to need its volume button. And throw a good quality toslink optical cable in, and you're set!

Cheers,

Bon

PS: Sorry for the long post...