hey oz, here is what i got for you - maybe ill start a build thread, maybe not :p
this is what i put on my car audio forum, diymobileaudio[dot]com[slash]forum under the car pc subforum. i have been competing in MECA sound quality as part of a small group (11 of us) on Team DIYma. I plan on taking this setup to the MECA north american sound quality finals to compete in Mod Street class. here is a video walkthrough of my system;
Originally Posted by req
Thanks for the post, it's awesome to see you able to do well in SQ using the Alpine H701 with just one set of mids! Very cool. Was good to see how you setup the channels for tweets and 'rears' etc. I guess having optical audio just takes away any concerns about interference or loss of quality which is exactly why I'm using the same brain.
I may have gone a little over the top with the plan for mine, as the H701 has a dedicated tweeter channel, two fronts and a rear, I've gone and bought amps for all of them just so I can use all the channels ;) I have all the gear, just need to get the bits for the carputer - take a look at the schematic:
So yeah, not going for the stock look at all, and up till now I hadn't thought about doing any SQ as I know the guys spend a LOT of $$$'s - this system is just to crank the tunes as clean and hard as possible for myself.....
I'd better get a post of my own going as I'll be starting the build soon - FYI, the target of this install is a 2002 Nissan Cube, hence the name, Project: Xtreme-Fidelity Cubed!
Im also using my TOSLINK of my mainboard to transport the audio to my DSP (bit.one).
Its ok, but I have some issues with it. First there are a lot of very loud cracks and pops when the computer switches on or off (even though it has delayed thump control), or when Windows loads.
It also makes a little noise while not in Windows and has some ground noise, which is quite audible when you run your amps at higher outputs (though my old PXA-H701 wasnt better in that case either, it just shut down output completely, when there was no music running).
This has been the case with 2 different computers already, so I guess it is related to the DSP, because everyone says the bit.one and PXA-h701 are not the best ones noise-wise and theres even an hardware filter for the pops and cracks for the bit.one (which I am going to try soon). Im going to try the new Mosconi 6to8 DSP too. It sounds very promising. The Alpine PXA-H800 sounds very nice too, but its also very expensive. Anyway, I will check both of them, and will take the one thats best.
You should activate 24 bit output on your PC btw, if your DSP accepts it, because that helps reducing noise, too.
Just a little feedback.
the H701 has a noise floor, and its not something i enjoy - but then again - i compete for sound quality as a competition - so maybe im just insane.
i have heard the bit.one and the jbl ms8... nothing crazy to me, the features seem there - but the interface is annoying as far as user control - and im not giving the p-dsp that i have any room because i dont like the interface for this either - specifically the fact that one can not change the size of the control screen - it only works above a certain resolution... its really irritating - thanks audiotec fischer, but the bit.one does this too if im not mistaken.
i do agree with the noise from the 701. its not the greatest, but again - mine is like 10 years old or better? so maybe, who knows :p
i would wait on the mosconi. i have a friend who has no speakers because the mosconi destroyed them all from some crazy failure. keep your eye on it - but give it some time to mature, at this stage i would not trust that piece of hardware in my system due to the stability problems. and the h800 is nothing but a cheaper version of the h700\701. it was tested with an o-scope and what not, it has a higher noise floor than the h700\701 does and does not do anything new, and none of the issues people had with the 700\701 were sorted or changed. im really dissapointed with alpine.
hopefully ill have the connector for the pdsp to install the analog volume pots soon because i cant install my carPC until the volume knob is ready - as SPDIF and TOSlink do not have volume control.
basically at this point - i have centrafuse on the PC - i had to do a windows7 regular install because it does not work with tiny7, and im OK with that. i got 40gb of music on my SSD at this point, and im just hung up on the volume control and one more issue.
basically there is a key sense wire for the picoPSU to trigger power-on. i set the PC to go to hybernate when the power button is pushed (ala- ignition key removed) and it shuts down hybernation style with no problems. but when i trigger 12v on the ignition to boot it back up, it hangs post windows with an error that says the hybernation state may have had an error, do you want to continue loading hybernation data or would you like to boot fresh.
ill figure it out :P
Yeah I heard about the problems with the Mosconi, but I also read that its already being fixed and can be avoided by a few precautions. Im going to try it in a few months, maybe even only next year. Still need new amps and speakers.
Originally Posted by req
Still, people say it has almost no ground noise, and thats very important to me. The ground noise of the bit.one is driving me nuts. If only it would also shut off the output when there is no signal, that would be enough already.
Didnt know the H800 is so bad, but It doesnt really surprise me... I already was pretty disappointed with Alpine.
You cant change volume over your PC via TOSLINK? Thats weird. Worked fine for me with every PC I ever had.
Had a Hibernation error like that too. Turned out to be a USB device that caused it. Might wanna try it without any USB device connected.
from what i have heard from my fellow DIYMA teammate, mic wallace (ala mic10is on diyma) - the pdsp has no noise using rca inputs. so thats good news on my side of the fence. people using the miniDSP have been having good success as well - and thats what the mosconi is based off of.
there is a thread about the h800 impressions buy a guy named erin henderson (ala bikinpunk also on team DIYMA), and he puts the h800 through its paces, and basically its nothing new over the h700, but its basically not as good.
as far as the transports that i have used that have optical - none of them have had any volume control over optical\spdif. if the computer does that - then great, if not then whatever. but i would still rather adjust volume AFTER the DAC. for ever 6 bits of data that is attenuated digitally, the input signal suffers for the DAC, so adjusting volume prior is a bad idea. it is in our best interestes to adjust volume in the analog relm if possible - this will prevent LOTS of funny noises and sounds.
hopefully the PDSP being connected isnt the cause of the error, ill try and unplug everything - i may have to have some kind of toggle for the USB connection of the PDSP... i had planned on having it always connected.
Never had any noises when changing volume. Works perfectly.
Originally Posted by req
Good luck on your problem, let us know.
well with the H701 ive got, there is a volume "zipper noise" that i dont know what the deal is, as the volume changes up or down with the rotary knob for the RUX-C701 - it will make clicking noises.
but as far as digital input to a DSP is concerned - the weaker the digital signal input is, the harder the amplifiers have to work in order to retain the same amplitude, this results in higer THD levels and such things that eventually will become audible to the human ear - so its obviously not good.
but if we retain the same input signal on the digital side, then the output voltage of the DAC is as high as possible and we retain the lowest THD for the amplifiers. all amplifiers do is multiply voltage, so 1v in and 10v out kind of thing. so if we have 5v in and 10v out, the amplifiers have to do less work you know?
thats where im comming from :)
Thanks for the heads up regarding these Toslink/SPDif issues - I'll build the system and confirm what the behaviour is!
So everything is installed, but when windows resumes or boots and it goes from the "resuming windows" loading screen I get a nasty turn on pop. I was thinking if I could get the amps to come on after that point then I could avoid the noise but if I'm going to have the pc boot cold then the wait needs to be longer... I need to find a way to get rid of this noise!