# Please Critique my Car PC system



## JdotP17

Here is a screenshot of my envisaged Car Pc system.








[/URL] Uploaded with ImageShack.us[/IMG]

http://img245.imageshack.us/f/59598966.jpg/

- 1TB Hardrive connected to Laptop for Music Library

- 8" lilliput touchscreen monitor to control laptop from inside glove compartment.

- Audio control four.1 splits DAC 2 Channel Signal to Front and Rear outputs of Audiocontrol, includes overall volume control (No headunit) and fader + rudementary equalisation.

- 4" Midrange will be run off the Compact 4 Bridged

- 6.5" Bass will be run off the Four Channel Bridged

- 3-way Rear setup will be run of the Four Channel Bridged.

Im mainly considering the feasability of the project & the overall SQ vs a contemporary Car Audio system aka Headunit > amps > speakers.

Cheers


Joe


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## MarkZ

I don't see what there is to critique. It's been done a thousand times, so obviously we know it works. Do you have a specific question?


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## JdotP17

I just wanted to see if I had any major problems with my proposed setup i.e 3-way front & 3-way rear passive possible? too difficult?, but as long as theres nothing sticking our in terms of problems that was all I was wondering.

I would like to know however, how people power their laptops i.e to the cars battery instead of using the laptops internal power, routing it directly to the battery or maybe to the cars lighter plug?

Thats all,

Thanks in advanced,

Joe


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## MarkZ

In your app, since you have external processing, you're only using the carPC as a glorified ipod. I don't think you'll run into any difficulties.

Not sure how you plan on powering it. It seems you'll need a power inverter to get 110v. Otherwise, you can buy a carPC power supply with the appropriate voltage output to the laptop.


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## The Baron Groog

Hello fellow Englander

Are you building the passives for the front yourself?

Laptop power is easy enough, plenty of inverters on fleabay.

Not running any subs?


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## Thunderplains

Jdot.. Wow this looks very familiar.. (me)

So I was in the same bucket as you, some things to think about..

Amps & Speakers.. Right on.. can't do much better than that..

Do you REALLY NEED rear speakers?? Going to have people in the back often?
Why not have that other Genesis amp feed a XK13 (I think I got that) in the rear?
Also, I was going down the path of a lap top, too complex for audio
IF that is where you are going, , Why not get a Pio P5200DVD & a audison bit one..
It will give you exactly what you want, less $$, MUCH more SQ control and look better in the dash.. I run a P5200BT and have a 250GB HDD connected to the USB as a music server (until I get the p99 online)

It will lessen your connections and really give you good control. SO unless you NEED a laptop for anything else, might want to simplify it.. It will help with troubleshooting down the road. 

BitOne - GREAT processor and all you do is run the fronts and sub-outs to it form the HU


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## JdotP17

Hi all sorry for not replying, 

The Baron Groog:  Hi there, yes I plan on building the passive fronts and rears myself, i hope its not too much of a challenge as im only 18, first car, first system, but I really dont like the general sound of contemporary car audio (Headunits) so I though id put my knowledge of Hi-Fi and my love of good quality audio to good use. I Plan on installing subs at a latter date, I just really want to get my front end sound good first, im sure the components themselves can produce a decent amount of low-end, ill relieve their strain later, I will probably power the sub (fi 12"/ morel) with a Genesis profile sub ultra amp.

Mark Z: Thanks for the advice on powering the latop, I will look into what youve recommended after Ive sorted out building an external power on button.

Thunderpants:  Thanks for the support, im glad ive chosen good components, as im 18 I can guarentee about 90% of the time ill have a full car blaring some not so high quality music aka Drum and bass, garage, dubstep, in which case for the passengers pleasure mainly ive chosen decent, but not top notch components primarily just to fill the back with a 2 channel signal split to the rear. The reason ive gone down the Laptop route is because I use a specific media player called foobar that produces bit perfect audio via ASIO to my external DAC on my home pc and it sounds on par with my dads hifi consisting of Linn Kan speakers, Naim DAC and EAR valve amps. The laptop to HDMI touch screen will give me the abily to see all my tracks, create playlists in seconds (drag and drop) tweak audio crossovers, time alignment, EQ on Laptop and send the signal to a high quality external DAC. Furthermore the Headunit you recommened (P5200BT) is £570 New whereas my laptop cost (im afraid ive already purchased it) £200. In addition the internal DAC of the P5200BT will no doubt be sub par as it is not mention in any product descriptions, it neither has jitter reduction or dual dacs as my proposed dac has. I have also looked into a processor as ultimately I want to go ACTIVE instead of PASSIVE, if I do i will look into the JBL Ms8 specifically.

Thanks to all for your suggestions and advice.

Joe


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## MarkZ

Joe, I use foobar2000 in my car rig too. I don't see anything particularly wrong with using a laptop. I've been doing laptop installs in cars for about 10 years. But the past couple years we've seen the advent of quality power supplies to power mainboards directly. This would solve your power button issue. Check out something like the Carnetix P1900 or M1-ATX smart power supplies. Not only do they have smart power on and off, but they also have delayed remote (for your amp), 5v accessory outputs (for external DACs/sound card), etc. I know the P1900 has selectable output voltages between 18-20v, so if your laptop operates on that voltage, you're good to go.

Anyway, I'm not sure how you're doing time alignment and crossovers on your laptop with external processing. What am I missing?


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## t3sn4f2

Joe an intelligent power supply like Mark suggested will be a good idea, since you will need a regulated 12 volts DC supply for the DAC. Something from Carnetix with an output for the laptop, monitor, and DAC (an add on piece) would be good.

Also, you might want to contact Cambridge and ask if you can send the DACmagic, a dedicated regulated 12 volt supply from the PS I mention. The back of the dacmagic specifies that you can only connect the supplied AC adapter to it. That might just be a generalized recommendation to protect themselves from idiots who don't know about electrocnics, but check just in case.

Opps the addon thrid voltage supply from carnetix is 5 volts so that wont work for you, You might be able to run it in parralel off the monitor's 12 volt output though.


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## JdotP17

Thanks to both of you for your information, I have just sent cambridge audio an email regarding the power issue.

Just out of curiousity Markz, what sort of method, if any do you use to externally power up/down the laptop from the drivers position if for instance the laptop is situated in the glove compartment. I have seen some redumentary DIY jobs to create little power jumpers from the audio output but nothing solid.

Thanks in advanced,

Joe


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## MarkZ

This is why I switched to using just a regular board, so that I can tap directly on to the power jumper on the motherboard. Laptops are a lot more difficult to work with, IMO.


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## The Baron Groog

Looks like you'll have a formidable system when you're done-however I would definitly go for the sub over the rear speakers in the initial install-DnB and Dubstep will cause you issues with your midbass-even with heavenly fabrication if you're going to blast those types of genres you're going to quickly wish you'd fitted a sub or worse-destroy a driver...

What car is this going in?


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## JdotP17

Cheers MarkZ, Ive found an alternator outboard power button DIY job that ill try and do, should cater for my needs.

Baron Groog: Hi, your probably right, I was just alway under the misconception that a decent sub needed serious TLC i.e to get the right frequency in the box, crossover, build the right box & then getting it to implement well with the rest of the system, although tbh thats why I got into car audio because I cant blast the sorts of music I like in my house (angry neighbours). The car that I 'will' be purchasing will be a vauxhall astra 2001/2002 mk4 G, ive already checked the speaker sizes for the front & rear doors and check the space in the glove compartment and centre unit, all is in order, my friend has the 4 door version, id like the 3 door.

Thanks again,

Joe


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## The Baron Groog

Joe, not to p!ss on your bonfire or put you down/off but I'd probably go for a 2-way plus sub over a 3-way plus sub for the 1st phase-implimenting 2-way plus sub and getting good results is much easier then getting 3-way minus sub or with sub to sound as good. 

The fabrication of a sub enclosure is really easy compared to doing builds for your mids, which you'll have to do in the Astra! I really admire your enthusiasm, but sometimes you need to walk before trying to run. From the mistakes you make in the 2-way set up you'll learn and adapt for the 3-way. It'd also allow you to go active using the amp's built in x-overs, which IMO would be easier for you to execute well then building the passives for your 3-way set up.

Rears in that vehicle will be an expensive option and not really worth it IMO, much better to go for a subwoofer instead.


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## JdotP17

Thanks for your advice Baroon Groog, my dad said exactly the said thing yesterday when I asked him about 3-way. Im thinking about ditching the focal rears all together and buying raw drivers of peerless.

What do you think of these two components for rear fill:

https://www.madisound.com/store/product_info.php?products_id=543

&

830946 - Peerless SLS 6.5 inch coated paper cone AL shorting ring in magnet system - Europe Audio

Focal sets are very expensive for what they are as ive heard some raw drivers are just as capable.

P.s how do I go active using an amps crossover? My genesis amps can either do high pass or low pass, not both i.e bandpass so i was planning on using the amps crossover to filter out some frequencies i dont want and use a crossover board thus giving a little more power to the amp?

Again the only reason I wanted to go 3-way was because I doubt ill be able to build kicks for the astra and so I wanted to have the tweeter and mid in A pillar in a pod and 6.5 in the doors, with a 2-way the tweeter will be seperated by quite a distance from the midbass in the door, will I have any imaging problems? Thanks, furthermore ive just aquired a DRC digital correction Room software to calculate peaks and dips in the interior, all i now need is a microphone to use the software. Do you think this will help with sorting out the cars acoustics? I think its similar to the software in the Bitone and Ms8.


At the end of the day I really want to astound my mates with the sonic bliss of my system  I dont want to spend all this time planning and putting so much money into the project for it to end up sounding like most peoples sony xplod setups, I really appreciate your help as I want to make sure im doing everything right first time (I know ill make mistakes but hopefully no major ones) so i dont have to spend even more money correcting my mistakes.


Joe


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## The Baron Groog

Are you sticking with the Focals for the front?

If you go to 2-way front end and sub and do it right you will blow away your mates.

The cross-over in the amps is HPF or LPF so you use the HPF on the tweeter and LPF on the mid-ideally your source would allow you to do a lower HPF on the mid so you can cut it off 60-100Hz (freq depending on other factors) otherwsie an active crossover between your source and amps will do it with no loss of power to the amps and better control then most source units will offer.

If your laptop only has a stereo output unless you go for point source drivers your mids/tweets being mounted in different positions will screw up any TA that can be done with software on the laptop. An RTA function will be beneficial as well as a good EQ function.

The tweeters I cannot really comment on-except I've never been a fan of metal/plastic/ceramic domed tweeters and ALWAYS go for silk, I've a £600 pair of Utopias gathering dust because I don't like the tweeters (they were a, speculative, swap not a purchase-I've never been a fan of focals and thought I'd give them a go)

The midbass seems to drop off steeply at 700Hz so would be a poor choice as a 2-way unit, if you're going for three way and your mid-hi happily plays down to 400-500Hz then it would be a usable driver, if 3-way and using the tweeter above the mid would have to comfortably play up to 2500Hz minimum (or 2-way the midbass would have to play to 2500Hz)

If you want to call me to chat about this pm me and I'll send my number

G


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## JdotP17

Thanks for the offer Baron Groog, ill take you up on that later, a little busy atm but I do have a revision of my propsed setup for you to have a look at in the mean time.

Both Four Channel & Compact Four are bridge to the speakers.

This Setup will save me a lot of money, plus installation time and setup hopefully.








[/URL]

Joe


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## The Baron Groog

Should be an easier install for you and easier to tune on your 1st, serious, attempt at car audio. Personally I'd still be inclined to forget the rear speakers, and use the cash saved from that elsewhere in the system-for example upgrading from the 4.1 to a 3-way active crossover or even better to something like Audison Bit1/JBL MS8-this would give you the advantages of TA and being able to run each channel actively-hell, you could do it just with an ipod and save all the faffing with laptops etc!

If anything I'd run the rears off the ST100 and use the two 4ch to power the fronts alone...

I've read good things on the Fi subs, but have no direct experience, but in the right box it should put a big grin on your mug Let me know your box requirements and I can design one for you.


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## Thunderplains

The Baron Groog said:


> Should be an easier install for you and easier to tune on your 1st, serious, attempt at car audio. Personally I'd still be inclined to forget the rear speakers, and use the cash saved from that elsewhere in the system-for example upgrading from the 4.1 to a 3-way active crossover or even better to something like Audison Bit1/JBL MS8-this would give you the advantages of TA and being able to run each channel actively-hell, you could do it just with an ipod and save all the faffing with laptops etc!
> 
> If anything I'd run the rears off the ST100 and use the two 4ch to power the fronts alone...
> 
> I've read good things on the Fi subs, but have no direct experience, but in the right box it should put a big grin on your mug Let me know your box requirements and I can design one for you.


I second that.. and if you are not going to run the KRX2 set up front and go to 2 way, I would look into the Scanspeak stuff.
VERY VERY good.


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## JdotP17

Thanks for you suggestions thunder pains, however scanspeak equiptment seems to be a lot of $$$ so I think, as of now ill stick to simple component setups until im a little more experince and further along with my install. 

Baron Groog this is my latest alteration in regards to your 2-way front + sub design, by not purchasing rear component speakers and the nessesary amp that then allows me to allocate the funds towards the JBL ms8 processor in order to go fully active for the front stage. What do you think?








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Im guessing there is no internal DAC in the ms8 as ive seen other after market headunits hooked up to the JBL before.

Joe


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## MarkZ

I don't get the need for the four.1 if you're using an MS8.

Also, have you considered not using any signal processors, and instead using the computer itself to do the signal processing? This is what I do. You can go the conventional route and use a VST host like console or audiomulch with VST plugins to do crossover, time alignment, level controls, etc. Or you can use an assortment of foobar2000 plugins to pull it off. There's a foobar crossover which is pretty good (foo_dsp_xover?). Play with that on your home PC for a while.

Alternatively, read this thread:

http://www.diymobileaudio.com/forum...-carpc-sound-processing-using-foobar2000.html


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## JdotP17

Well in my opinion I need the audiocontrol four.1 as a stand in Headunit for master volume, fader and primitive on the fly EQ'ing, the JBL dosent have a volume knob or fader knob as its all done on a slow, small screen.

The JBL ms8 splits the two channel signal from the DAC to 8 channels to seperate amplifiers, with just the laptop I would only have 2 channle, i.e left and right audio which you cannot apply a crossover for high, mid and low, you would need 2 channel just for the highs, then 2 for mid and 2 for low.

Joe


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## MarkZ

Have you considered using a multichannel sound card? The four.1 is a bit of a waste if you only plan on using it as a volume knob. Why not use the foobar2000 volume knob? What about the volume knob in your diagram?


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## The Baron Groog

JdotP17 said:


> Thanks for you suggestions thunder pains, however scanspeak equiptment seems to be a lot of $$$ so I think, as of now ill stick to simple component setups until im a little more experince and further along with my install.
> 
> Baron Groog this is my latest alteration in regards to your 2-way front + sub design, by not purchasing rear component speakers and the nessesary amp that then allows me to allocate the funds towards the JBL ms8 processor in order to go fully active for the front stage. What do you think?
> 
> Im guessing there is no internal DAC in the ms8 as ive seen other after market headunits hooked up to the JBL before.
> 
> Joe


I'm not overly familiar with the MS8, but know users who rate it highly-speak to Yuri on here-another Brit who's local to me and helped with my install and loves his audio-has a couple of Aliantes in the front doors of one of his cars and 8x 5" Focal subs in the other

The setup now looks a lot more tunable and should give better results then the previous setups-deffinitely a step in the right direction

As said by others you may be better off going for processing in the laptop(seems a shame to waste it) but I type with one finger and generally do everything I can to avoid them-so can't really help there! Though can't see how you're going to get 8 outputs of a laptop-an incar pc may do it.

G


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## MarkZ

The Baron Groog said:


> Though can't see how you're going to get 8 outputs of a laptop-an incar pc may do it.


ESI - GIGAPORT HD


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## JdotP17

Thanks all, just to clarifiy the audiocontrol four.1 is a master volume controling the power of the amps, the volume control connected to the laptop control the volume of the foobar player, track forwards & backwarads and scrolling. Furthermore ive already purchased the laptop, and for the £200 price tag I managed to aquire 4gb of DDR3 ram, dual core 2.2ghz processor, 320gb Hardrive & a really good graphics card (8500m?) Either way Im unsure I would have been able to get the same deal on a car pc desktop computer as I did with this laptop, no cooling issues with a laptop. In additon ive tried many computer soundcards in the past (Latest Asus Xonar Essence) and have been thoroughly disapointed with all which is thus the reason Ive gone with the external DAC as it is the same setup I have on my home PC. In regards to using the laptop as a processor, I do have many Vst plugins for processing and some very intuitive equalisers however I would like to do the bulk of any processing outboard and if I did get an ms8 its superior software and tuning abilities will most likely trump the laptops methods. Im really only using the laptop as a Media hub with an external 1TB hardrive connected, a media player with superior bit-perfect audio playback and as the source for the touchscreen monitor. I like to be able to see the whole picture of what im doing which is thus the reason ive gone with a car pc, I really despise the constrained screens of headunits and fold out screen-headunits.

I hope this clarifies a few things.

Joe


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## The Baron Groog

MarkZ said:


> ESI - GIGAPORT HD


Nice bit of kit-will it allow you to filter the outputs?


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## JdotP17

Regarding the ESI - GIGAPORT HD, I apprecaite the suggestion however I really dont want to rely on such a small box to provide me with the SQ for the rest of the system, this is where music is made i.e 1's and 0's into music - Id much rather it be this with much superior components (http://www.tossaudio.be/images/stories/cambridge-audio/Cambridge Audio DAC Magic front.jpg)

Would you use an mp3 player to form the hub of your SQ system?

Joe


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## MarkZ

Two things. First, if you get the MS8, the quality of the DAC you use is pretty much meaningless. You'll be performing a D->A conversion, and then the MS8 will be converting that back to digital and then again to analog. So I wouldn't worry too much about getting the best DAC you can on the front end, since ultimately the MS8 DAC will be introducing a conversion too.

The only thing about the MS8 tuning that's superior to the laptop is the auto-tune feature and Logic 7. Other than that, VST plugins are far more versatile than the MS8's relatively limited capabilities. Since you're not using a center channel or rear fill, I don't really see the point in choosing the MS8, to be honest.

If you insist on using external processing, you might want to consider something that also serves as a DAC. This will save you a processing step and maybe some money. I don't know if the bit one does this or not. You could always go with the Behringer DCX2496, but the thing is huge (1u rackmount) and has funny digital inputs (AES/EBU).


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## JdotP17

> First, if you get the MS8, the quality of the DAC you use is pretty much meaningless


If this is the case why would anyone ever use this with an aftermarket headunit i.e P99rs as it basically negates the whole point in the HU dosent it?


Well the MS8 isnt entirely nessesary I could just go back to the 2 channel front split to the 2 front amps and do the processing from the laptop via Digital room correction software (similar to MS8).

In my opinion the two most important components in a system is the amps then the DAC which is why I really am reluctant on any less than a similar external hi-fi dac.

Is there any outboard piece of kit that can route my 2 channel signal into 8 output active crossover without adding extra DSP's / DAC's to the mix?

Joe


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## MarkZ

I use the ESI Gigaport HD in my setup. It will give you a cleaner signal than two D->A conversions, like what you're currently proposing. If I'm not mistaken, I believe the DAC in the Gigaport actually has the same noise+distortion performance as the DAC in the Cambridge:

http://www.asahi-kasei.co.jp/akm/en/product/ak4584/ak4584_f00e.pdf
http://www.lampizator.eu/lampizator/LINKS AND DOWNLOADS/DATAMINING/tda 1541A.pdf

I believe those are the two DACs in question.

And yes, I use LAME-encoded V0 mp3s.  If you're trying to improve sound quality, you're looking in the wrong place. Invest in better speakers and VST plugins and it will have a much much bigger impact, especially in a car where you have to spend so much time fighting the environment.


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## MarkZ

JdotP17 said:


> If this is the case why would anyone ever use this with an aftermarket headunit i.e P99rs as it basically negates the whole point in the HU dosent it?


Because lots of people place greater importance on the ability to tune a system to correct for the crappy vehicle environment, than they do on things that happen in the electrical domain.



> Well the MS8 isnt entirely nessesary I could just go back to the 2 channel front split to the 2 front amps and do the processing from the laptop via Digital room correction software (similar to MS8).
> 
> In my opinion the two most important components in a system is the amps then the DAC which is why I really am reluctant on any less than a similar external hi-fi dac.
> 
> Is there any outboard piece of kit that can route my 2 channel signal into 8 outputs without adding another DSP/DAC into the mix?


No, but I have heard of people stacking DACs. I don't know how this would work with software processing though. But it might be possible if you can route the outputs with something like Virtual Audio Cable.


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## JdotP17

Just to let you know this could be my propsed setup

Laptop>DAC>AudioControl Four.1>*AudioControl 6XS(Active)*>Amps>Speakers

AudioControl 6XS could provide me with the 2 channel to 8 ouputs to go active that is all I need.


With the Laptop I can do the processesing required to equalise the peaks and dips in the enviroment by using DRC software whilst maintaining high fidelity sound from the DAC and being able to go active with the 6XS.

Joe


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## JdotP17

> If you're trying to improve sound quality, you're looking in the wrong place. Invest in better speakers and VST plugins and it will have a much much bigger impact, especially in a car where you have to spend so much time fighting the environment.


I totally understand but im the group who believes the less processing the better, too much processing and you degrade the audio signal.

In additon in regards to DAC's most of the time its the internal circitry which determines how good the DAC will perform, this is the reason most HU's sound pretty much the same.

Joe


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## The Baron Groog

I'd bin the 2 audiocontrol units and either go for the USB 8 outputs device or for the MS8...Doesn't your touchscreen allow you to do volume from it?


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## MarkZ

Well, I can't speak for the Cambridge audio device, but I can for the ESI. There's barely any internal circuitry.  It's bus powered, so there's no power supply. The output of a USB decoder goes directly into the DAC (literally). The signal out of the DAC goes through an anti-aliasing filter (simple capacitor/resistor network), an output op amp, and muting circuit. The muting circuit is easy to bypass if you so choose. So, the only place where the signal could potentially be degraded is the op amp. IIRC, the ESI uses an LMV722 (or is that the Transit? I forget...).

http://www.national.com/ds/LM/LMV721.pdf

THD+N for this op amp is 0.001%

I plan on testing this ESI sound card sometime soon. Based on its components (a reasonable DAC, a within-spec op amp, simple output circuitry), I expect it to perform about as well as any other. But I realize without the test results, my argument might not be very compelling.

Anyway, I understand your goals, and I even understand the preference some people have for analog filtering, but I think you might want to rethink your stance on time alignment. Sample-perfect (I just made that term up ) time alignment, by definition, imparts no artifacts into the signal. You're just shifting by a given number of samples. I think you'll find that it's incredibly important in the car, primarily to account for the asymmetries in the vehicle (we sit on the left, not in the center) and the interaction between the sub and mid.

Edit: I should also point out about the ESI, for others reading this, that the output voltage of the DAC is higher than the output voltage of the device itself. Why? Because the op amp circuit attenuates the output. For anybody who wants to use this card at a higher output voltage, you only have to change one resistor per channel. A word of warning though -- these are microresistors which are a ***** to solder. [I like the output voltage where it is, because it allows me to bypass the entire front end of my amplifier, including the gain circuit... ]


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## The Baron Groog

^Agreed-time alignment is a much more important factor then this, that or the other DAC in the car enviroment


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## t3sn4f2

opamps:

I have a cheap emu-0404pci that measures better then the best headunit out there. It has cheap JRC opamps. THD at 2 volts out is .001% and the resolution limit of a CD file is .0003%. When I play something and lower the digital volume to -130db, I hear NOTHING on the headphone, no hiss what so ever and that is without a zero bit mute active since I am playing something.

http://www.diymobileaudio.com/forum/member-product-reviews/77343-iphone-3gs-unloaded-headphone-out-measurements.html#post993753


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## Thunderplains

JdotP17 said:


> I totally understand but im the group who believes the less processing the better, too much processing and you degrade the audio signal.


Agreed. My setup.. P99RS -> Levithan/Kronos Amps (Burrbrown DACs) -> speakers. I run all my music lossless on an iPod.


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## JdotP17

Maybe I should just run the laptop optically to a pioneer rs-d7rii?

Would this work, i.e Laptop with a usb-optical device into the Pioneers optical input (i.e the processor/CD input)? I could then use the pioneer as volume control, fader, processing, TA and EQing and Active crossovering.

Think its feasable? 

How many outputs does the rs-d7rii have? I need front, rear and sub or front high, front low, rear and sub.

Markz im greatfull for all you suggestions but the whole reason I wanted to go down the car pc route was basically to try and replicate my Home pc hi-fi as much as possible, otherwise I might have well have got a cheap HU with that ESI soundcard.


Maybe I could use the audio-out from the laptop into the auxillary in of a headunit+processor (TA, EQ, Crossover)?
*
Laptop>P90 Combo>Amps>Speakers? Would this work? i.e Laptop to auxillary in of headunit?*

OR
*
Laptop>Clarion HX-D2>Amps>Speakers?*


Joe


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## MarkZ

JdotP17 said:


> Maybe I could use the audio-out from the laptop into the auxillary in of a headunit+processor (TA, EQ, Crossover)?
> 
> Laptop>P90 Combo>Amps>Speakers? Would this work? i.e Laptop to auxillary in of headunit?
> 
> Joe


It'll work, but I don't see what you're trying to achieve. Somewhere along the line, you got the idea that the single ESI D->A conversion step is inferior to your laptop's onboard D->A conversion + a head unit's A->D conversion + the head unit's D->A conversion.

You can try your other idea (the optical into a Pioneer sig proc), which will reduce the number of D/A conversions, but it's not clear to me that this Pioneer processor's D/A converter is better than the ESI's.

BTW, there are other multichannel audio cards out there other than the ESI. I just suggested the ESI because it's cheap, I use it, and it has ASIO drivers. If you REALLY want external vol control, you could consider one of these to use as your DAC:

M-AUDIO - Fast Track Ultra 8R - High-speed 8 x 8 USB 2.0 Interface with 8 Preamps and MX Core DSP

That would look nice under the dash or ctr console. 

Although I strongly suspect it uses the same DAC as most of the other M-Audio cards, including the Transit which uses the aforementioned AK DAC.


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## JdotP17

Markz i believe this is the perfect setup, check it out. Everything is catered for.

The laptop will use a usb-optical out which I use on my home pc which acts like a soundcard (disabling the laptops DA converter) to send the signal to the Headunit to do the processing and send the audio to the amps.

The Clarion HU has:

4-way active crossover 
Time alignment
Graphic & Parametric EQ
Gold plated RCAs
24bit dua burr brown dacs
Its own powersupply
Optical In








[/URL]

Joe


----------



## t3sn4f2

JdotP17 said:


> Markz i believe this is the perfect setup, check it out. Everything is catered for.
> 
> The laptop will use a usb-optical out which I use on my home pc which acts like a soundcard (disabling the laptops DA converter) to send the signal to the Headunit to do the processing and send the audio to the amps.
> 
> The Clarion HU has:
> 
> 4-way active crossover
> Time alignment
> Graphic & Parametric EQ
> Gold plated RCAs
> 24bit dua burr brown dacs
> Its own powersupply
> Optical In
> 
> 
> 
> 
> 
> 
> 
> 
> [/URL]
> 
> Joe


Which USB to optical converter do you have?


----------



## t3sn4f2

Also has anyone ever compared ASIO to Directsound out in an inverted sampled aligned comparison. You know, you recorded the directsound stream with a software that records streams sample perfectly (ie Applian Media Catcher 4.0 set to record audio in wave, it free for the first 30 sec. of the rec). Then you import that wav file to Audacity sound editor (also free). Then you import the original file you play to be recorded. Then you zoom and cut away the begin samples (you need to set the snap to in preferences to "samples" not "minute/sec" or others) till you align bot track digital sample to digital sample. Then you invert one of the to and play them both at the same time. Since each sample will then have a completely inverted representation you will not hear ANYTHING if the directsound stream was not molested by something. 

If someone wants to try this, be very careful with the end of the songs since those won't end in the same sample and the original will continue to play which will result in a full scale blast to your speakers if you cranked up the volume to hear any digital hash from the recording.

I've tried this with my card and ASIO and direct sound are both dead silent even at *130*db of added digital gain. The only thing that is heard there is the background noise of the 24bit DSP. But my card supposedly bypasses all windows media stuff like Kmixer and replaces it with it own stuff. Can't say for sure a stock USB to optical "USB speaker driver" will perform the same. Only way to know is to feed that stream by spdif to a computer that can record sample perfectly, then compare the way mentioned above. 

If anyone want the results in measured form instead of inverted comparison form that take a look at this thread http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/78835-asio-vs-drm-compatible-carpc-frontend-friendly-e-mu-directsound.html

The purpose of this test is to not be typed down to ASIO and be able to use other media players like iTunes and WMP that have more options on their GUI.


----------



## JdotP17

> Which USB to optical converter do you have?


This is the USB to optical converter I have.









And thanks for your input on ASIO / Directsound, im not sure, but I do believe the Sony converter appears as a directsound soundcard on the foobar output options.

Joe


----------



## t3sn4f2

JdotP17 said:


> This is the USB to optical converter I have.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> And thanks for your input on ASIO / Directsound, im not sure, but I do believe the Sony converter appears as a directsound soundcard on the foobar output options.
> 
> Joe


Yup, it should since ASIO almost always comes with sound cards that come with drivers to install. They have their own ASIO drivers included. Will you be running "ASIO4ALL" in order to use foobar with ASIO and that converter?

Personally, I'm 99.99999% sure that the way it is now is bit perfect to an ASIO output. Take a look at the following link for a DIY USB to spdif converter. Go to the spec tab and scroll down to the RMAA measurements. There there will be a measurement of 44khz/16bit for the USB to spdif version of that device. It is identical to the perfect results listed for the RMAA measurements in the thread I linked above. That device uses the plain windows USB speaker driver that all driverless non specialize "USB to whatever" devices use. That means KMIXER and all other junk is in there, yet it's bit and sample for sample perfect to the original.

The γ1 Modular Miniature DAC

IOW, don't worry about ASIO unless you need low latency or for specialized DSP softwares. 

Also, don't believe that there is a quality deference in the media player used either. iTunes, WMP, Windows media center, winamp, etc., they're all sample perfect (ie bit perfect) as long as no EQ or DSP is turned on and their volume setting is set to max (same goes for the WAV volume slider in windows sound by the way, it needs to be set to max always). I've verified this with RMAA and with the inverted listening test. Identical and dead silence on all those players.


----------



## MarkZ

t3, I may be wrong, but isn't foobar2000's volume ctrl immune to some of the roundoff error issues that other players are prone to?


----------



## t3sn4f2

MarkZ said:


> t3, I may be wrong, but isn't foobar2000's volume ctrl immune to some of the roundoff error issues that other players are prone to?


Yeah Foobar's the only one that I know off, maybe Jriver also by now.  

Let me check and see how good it is........

Edit: I'm having trouble seeing how much attinuation it can handle while still inverting silently to the original track (recording at 24 bits). But yeah, I've read Foobar is fine in countless places. 

Normally in other invert test I've done for other player's volume control, the degradation is the only added white noise, but the song cancels out completly. Tonight with foobar, I can't get it to attinuated much, much less cancel completly. It's late.


----------



## JdotP17

Thankyou all for your help.

*However, I now need your help more than ever.*

----------------------------------------------------------------------

As my main aim is to use the laptop as a source for the headunit, going optically out from the laptop, these are my two setup choices. Please comment and advise on their credibility.

*Setup 1*

Headunit: Pioneer P88rs (Acting as Processor, Volume and fader contol only)

Laptop as source, going to a usb to optical convert which then feeds into the external DAC. The DAC then routes its signal to the Pioneer IP bus auxillary cable which feeds into the Pioneer headunit for processing. If im correct, using the auxillary as source uses the external sources DAC and not the internal DAC in the headunit (aka using an ipod uses ipods DAC), thus the headunit is just for volume and processing.









[/URL]


*Setup 2*

Headunit: Pioneer P99rs (Acting as DAC,transport and Processor)

If I am incorrect about the auxillary source using external DAC then I will use the laptop with usb to optical out to an optical to rca converter which will be connected to the auxillary input of the headunit thus using the headunits internal DAC but using the laptop as source.



Very much appreciate your comments, im not sure if the above will work.

Joe


----------



## t3sn4f2

JdotP17 said:


> Thankyou all for your help.
> 
> *However, I now need your help more than ever.*
> 
> ----------------------------------------------------------------------
> 
> As my main aim is to use the laptop as a source for the headunit, going optically out from the laptop, these are my two setup choices. Please comment and advise on their credibility.
> 
> *Setup 1*
> 
> Headunit: Pioneer P88rs (Acting as Processor, Volume and fader contol only)
> 
> Laptop as source, going to a usb to optical convert which then feeds into the external DAC. The DAC then routes its signal to the Pioneer IP bus auxillary cable which feeds into the Pioneer headunit for processing. If im correct, using the auxillary as source uses the external sources DAC and not the internal DAC in the headunit (aka using an ipod uses ipods DAC), thus the headunit is just for volume and processing.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> [/URL]
> 
> 
> *Setup 2*
> 
> Headunit: Pioneer P99rs (Acting as DAC,transport and Processor)
> 
> If I am incorrect about the auxillary source using external DAC then I will use the laptop with usb to optical out to an optical to rca converter which will be connected to the auxillary input of the headunit thus using the headunits internal DAC but using the laptop as source.
> 
> 
> 
> Very much appreciate your comments, im not sure if the above will work.
> 
> Joe


Setup 1:

In that situation you use the DAC magic DAC to send a analog signal to the head unit BUT the head unit then uses an ADC to convert the analog signal to digital again (to be processed by the head units DSP).

That's not necessarily something bad, but it would be a waste of money to send the higher quality and expensive analog out from the DAC mag into a mid level head unit's ADC. Whether that DAC is worsth it own its own is one story but to run it like that will certainly take away any advantage it brings.

That being said it's perfectly possible that a decently priced USB DAC going into that head unit will sound just as good as a digital output going into that head unit' digital input, _if setup up correctly _(hypothetical situation since that head units has none). 

You are also going to run into problem of possibly clipping the aux inputs by using the DAC magic's 2 volt analog out (I'm assuming that is it's rating here) into the head unit's typically rated 1 volt aux input rating. You will need to use a high quality resistor voltage divider between them, a good quality POT, or attenuate with foobar in order to make them work together without clipping the inputs of the head. Remember, if going with a driver less USB DAC, you can only use Foobar's volume control bring down the level of the dac to the needed output range. All other volume controllers in windows will add noise and an inaudible amount of distortion. 

Setup: 2

This setup is the same as #1. The DAC magic takes a digital stream from the PC and converter it to analog (along with some extra digital processing). The USB to spdif connected to the Spdif to DAC does the same thing except that it uses different forms of digital transmission from the PC to the DAC stage. 

IE DAC magic = USB>i2s>DAC (I excluded the advanced processing the DAC magic does to keep it simple and to the point)

Setup 2 = USB>i2s>spdif>i2s>DAC

i2s is an internal form of transmitting digital info. between circuits. SPDIF is an external form. The added steps DO NOT degrade that digital signal AT ALL (I've tested it).


If you want to go with the second setup for that excellent headunit's properties, then find a good quality DAC who's output is rated for what the AUX in can handle. Something driverless so you can hibernate the laptop with the laptop without issues. Maybe one with a slightly higher output voltage that way you can pad it down to exactly the voltage you need which will make all the headunits sources be at the same volume.

Or if you can live with this, use the USB digital input on that head unit to control and be fed from the digital stream of a high capacity iPod. That's what I would do probably. Or maybe from a high capacity USB drive, dunno if that will work with this head or if it is bug free and easy to navigate.


----------



## JdotP17

Thankyou for your expertise, im pretty frustrated though tbh as I cant seem to find a plausable solution to my requirements. 

There is one last solution however, and that is to go from my laptop to a usb to optical converter, then to an optical to coax converter with a female co-axial plug connected with 2 female rca outputs to which would connect the rca male inputs of the pioneers IP bus connector. Theoretically this would keep the signal clean without a D/A conversion inbetween.

It would however require the higher quality headunit as with no other DAC in the chain I would need good internal components of the specific headunit.

Hopefully I will be able to use the laptop as source, apply any attenuation gain/reduction in foobar to match headunits voltage and then use the headunit for volume, fader, eq, time alignment, crossovers and to route the signal to the amps.

P.s why is Auxillary quieter than normal CD input? Is it purely to do with voltage and if so can it be increased to match normal signal level?

If so could I use an audiocontrol overdrive to boost the voltage from the laptop to the same as the headunit?

Thanks

Joe


----------



## JdotP17

Ok im really pulling my hair out on this one, but I think this solution might just work.

Route of Signal

Laptop >
Usb to Optical Converter >
Optical to Coaxial Converter >
Male to Female RCA Splitter >
Male RCA Cables >
Audio Control line out/pre-amp >
Male RCA Cables >
Pioneer IP Bus Female Cables >
Headunit Auxillary Input

_Reason for Audiocontrol Overdrive is to increase the laptops 2v output to match that of the headunit 5v._








[/URL] 

Joe


----------



## t3sn4f2

JdotP17 said:


> Thankyou for your expertise, im pretty frustrated though tbh as I cant seem to find a plausable solution to my requirements.
> 
> *There is one last solution however, and that is to go from my laptop to a usb to optical converter, then to an optical to coax converter with a female co-axial plug connected with 2 female rca outputs to which would connect the rca male inputs of the pioneers IP bus connector. Theoretically this would keep the signal clean without a D/A conversion inbetween.*
> 
> It would however require the higher quality headunit as with no other DAC in the chain I would need good internal components of the specific headunit.
> 
> Hopefully I will be able to use the laptop as source, apply any attenuation gain/reduction in foobar to match headunits voltage and then use the headunit for volume, fader, eq, time alignment, crossovers and to route the signal to the amps.
> 
> *P.s why is Auxillary quieter than normal CD input? Is it purely to do with voltage and if so can it be increased to match normal signal level?*
> If so could I use an audiocontrol overdrive to boost the voltage from the laptop to the same as the headunit?
> 
> Thanks
> 
> Joe


Pioneer ipbus does not carry digital audio, it is used to control and send data between them. Even if it did, which it definitely does not, it would not be something as simple as finding the appropriate hardware terminations to connect the two. I would be like plugging in your cars head unit power to the outlet in your house just because you attached a two prong home plug to the power lead of the deck. Just no that explosive though.  Digital signals are not all alike IOW.

As for the volume of the AUX source, yeah it's as simple as matching output voltage at 0dB to input voltage needs that make that source as loud as the other sources. You can match it by using a device that has a little more voltage then you need so that then you have enough to pad down that output and make it match. More then you need and not less because you can get more voltage out of something then what it give you at max setting.

Tell me again exactly what it is you want to do in detail.


----------



## JdotP17

Anyway Im not sure whether you noticed my diagram above?

P.s I didnt realise the p99rs had auxillary input on the front of the unit, in that case remove the IPbus connector from the diagram and replace it with a 2 to 1 RCA cable into the front of the unit.

Joe


----------



## t3sn4f2

JdotP17 said:


> Anyway Im not sure whether you noticed my diagram above?
> 
> Joe


Yeah, you're sending an S/PDIF coax digital signal into an analog signal only input of a line driver. Won't work and will probably fry something.


----------



## t3sn4f2

JdotP17 said:


> Anyway Im not sure whether you noticed my diagram above?
> 
> P.s I didnt realise the p99rs had auxillary input on the front of the unit, in that case remove the IPbus connector from the diagram and replace it with a 2 to 1 RCA cable into the front of the unit.
> 
> Joe


I would not use the front aux in as a permanent solution, that is for brief instances where you can live with the front panel being folded down in order to have the mini jack in there. The ipbus aux adapter is the same quality as the front regular AUX.


----------



## FlexnInLa

I'm no pro but that looks pretty damn neat to me!

Where is your substage?


----------



## JdotP17

Hi, thanks for the comment, my substage will be Fi Q 10" with a Genesis profile sub ultra amp.


Regarding the source

I believe this should 100% work, im just concerned of quality. Will I notice any degrade in sound quality using RCA analog line out instead of digital out?








[/URL]

Thanks

Joe


----------



## MarkZ

JdotP17 said:


> Ok im really pulling my hair out on this one, but I think this solution might just work.
> 
> Route of Signal
> 
> Laptop >
> Usb to Optical Converter >
> Optical to Coaxial Converter >
> Male to Female RCA Splitter >
> Male RCA Cables >
> Audio Control line out/pre-amp >
> Male RCA Cables >
> Pioneer IP Bus Female Cables >
> Headunit Auxillary Input
> 
> _Reason for Audiocontrol Overdrive is to increase the laptops 2v output to match that of the headunit 5v._
> 
> 
> 
> 
> 
> 
> 
> 
> [/URL]
> 
> Joe


D->A->D->A ... 

Remind me again why you don't want to use the laptop to do the processing?

Edit: Also, I don't understand why you're converting to toslink with one box and then converting the toslink to analog with the other box. What is that other box, anyway?


----------



## t3sn4f2

JdotP17 said:


> Hi, thanks for the comment, my substage will be Fi Q 10" with a Genesis profile sub ultra amp.
> 
> 
> Regarding the source
> 
> I believe this should 100% work, im just concerned of quality. Will I notice any degrade in sound quality using RCA analog line out instead of digital out?
> 
> 
> 
> 
> 
> 
> 
> 
> [/URL]
> 
> Thanks
> 
> Joe


I would not use the Laptops analog outputs, THAT is a low quality noisy source usually or almost always (always IMO ). Use a small self power low output voltage USB DAC which will resolve a CD files resolution perfectly and it not loaded with useless features. It SHOULD sound the same as the digital interface assuming the Pioneer's AUX/cdchanger input is up to the task (I think it is). If you can tell the difference between that setup and the built in head unit's CD transport, during a properly conducted double blind test. Then you are the man, the only man probably. 

A USB DAC like this one.....

ESI - Dr. DAC nano 

That one is high quality but it's a little too power since it's meant to driver headphones as well. You might have to pad down in foobar about 9dB.

Oh, as a side note. If you end up not using ASIO with foobar but instead go with the self install MME windows drivers, make sure that you set output format/post processing in the options to whatever format you are using (ie 16 bit) and NO DITHER! Using any of those will f up the sound considerably. Same goes for Winamp users, enabling 24 bit output mangles the signal.

Edit: Scratch the 24 bit part of foobar, I just tested it again and it outputs fine, Dither does however add a good amout of noise and winamp 24 bit out enabled still messes it up.


----------



## JdotP17

*Ok a few Questions:
*
1. When using auxillary input on the pioneer (s), does the pioneer use its internal DACs to process or the sources DAC's

2. When using the Laptop as source, will the headunit play back all audio regardless of the format from the source? i.e just acting as output.

3. I thought the voltage of the pioneer HU where 5v, why is auxillary 1v? Ive heard people complain about low volume with auxillary.

*A few Answers:*

1. I cant use the laptop to do processing as the signal im outputting is 2 channel, a headunit will take the 2 channel and split it to 6 with the added benefit of volume control, eq e.t.c

2. The USB to optical acts as a sound card (although no DAC, so I have to connect one) so I can select it in Foobar thus no noise from the laptop will be outputted only those inside foobar. It is also a high quality digital connection.

*
These are my main requirements:*

Laptop Source,
High Quality External/Internal DAC
Functionality of a headunit i.e easy access to volume (Knob), eq, crossovers. I need a volume knob and fader control, windows volume is not the same as a master volume of a headunit.


----------



## MarkZ

t3sn4f2 said:


> I would not use the Laptops analog outputs, THAT is a low quality noisy source usually or almost always (always IMO ). Use a small self power low output voltage USB DAC which will resolve a CD files resolution perfectly and it not loaded with useless features. It SHOULD sound the same as the digital interface assuming the Pioneer's AUX/cdchanger input is up to the task (I think it is). If you can tell the difference between that setup and the built in head unit's CD transport, during a properly conducted double blind test. Then you are the man, the only man probably.
> 
> A USB DAC like this one.....
> 
> ESI - Dr. DAC nano
> 
> That one is high quality but it's a little too power since it's meant to driver headphones as well. You might have to pad down in foobar about 9dB.
> 
> Oh, as a side note. If you end up not using ASIO with foobar but instead go with the self install MME windows drivers, make sure that you set output format/post processing in the options to whatever format you are using (ie 16 bit) and NO DITHER! Using any of those will f up the sound considerably. Same goes for Winamp users, enabling 24 bit output mangles the signal.


BTW...

It's worth pointing out that the AKM DAC in the Gigaport specs better than the AKM DAC in this "high end" device.  Check out the datasheets.

Gigaport DAC: ak4358vq
Dr. DAC: ak4421

(I just opened up my Gigaport to verify that this is in fact the DAC...)

Not that it's going to make an audible difference. I just felt it was worth pointing out that the 8-channel AKM DAC is every bit as capable as the two-channel. There's really no reason to limit oneself to two channels for the sake of sound quality..


----------



## MarkZ

JdotP17 said:


> *A few Answers:*
> 
> 1. I cant use the laptop to do processing as the signal im outputting is 2 channel, a headunit will take the 2 channel and split it to 6 with the added benefit of volume control, eq e.t.c


Right. My suggestion was that you let the laptop do the eq, crossovers, time alignment, level controls, etc, and output directly to the amplifier from it. I don't understand the point of the HU. If you want a rotary volume knob, which is understandable, you can buy USB ones that will adjust the volume within foobar2000.



> 2. The USB to optical acts as a sound card (although no DAC, so I have to connect one) so I can select it in Foobar thus no noise from the laptop will be outputted only those inside foobar. It is also a high quality digital connection.


It's not "high quality". It just converts one form of digital to another. Then you're relying on an external DAC to perform the digital to analog conversion. I assume this external DAC is that Cambridge one, right? I'm sure it's a fine DAC. But you're following it up by converting BACK to digital so that the Pioneer can do DSP. And then another D->A conversion within the Pioneer. Three stages of conversions!

The ESI Gigaport, or any other multichannel sound device, will perform better than this because it will only require one conversion. Likewise, feeding an external processor a purely digital signal will perform better because it will only require one conversion.

You're needlessly performing an extra set of conversions. Which isn't a big deal, but if you're hung up on the supposed quality of the digital-to-analog (or vice versa) conversions, then it is.


----------



## JdotP17

Thanks markz, but without a headunit giving me 6 outputs how can I do Time alignments and crossovers?

In addition the components of the 8 channel giga are poor

Joe


----------



## t3sn4f2

MarkZ said:


> BTW...
> 
> It's worth pointing out that the AKM DAC in the Gigaport specs better than the AKM DAC in this "high end" device.  Check out the datasheets.
> 
> Gigaport DAC: ak4358vq
> Dr. DAC: ak4421
> 
> (I just opened up my Gigaport to verify that this is in fact the DAC...)
> 
> Not that it's going to make an audible difference. I just felt it was worth pointing out that the 8-channel AKM DAC is every bit as capable as the two-channel. There's really no reason to limit oneself to two channels for the sake of sound quality..


True, and the lower output voltage will mate up better with the aux in, along with having less unneeded components in the way for the unused higher voltage output.


----------



## t3sn4f2

JdotP17 said:


> *Ok a few Questions:
> *
> 1. When using auxillary input on the pioneer (s), does the pioneer use its internal DACs to process or the sources DAC's
> 
> 2. When using the Laptop as source, will the headunit play back all audio regardless of the format from the source? i.e just acting as output.
> 
> 3. I thought the voltage of the pioneer HU where 5v, why is auxillary 1v? Ive heard people complain about low volume with auxillary.
> 
> *A few Answers:*
> 
> 1. I cant use the laptop to do processing as the signal im outputting is 2 channel, a headunit will take the 2 channel and split it to 6 with the added benefit of volume control, eq e.t.c
> 
> 2. The USB to optical acts as a sound card (although no DAC, so I have to connect one) so I can select it in Foobar thus no noise from the laptop will be outputted only those inside foobar. It is also a high quality digital connection.
> 
> *
> These are my main requirements:*
> 
> Laptop Source,
> High Quality External/Internal DAC
> Functionality of a headunit i.e easy access to volume (Knob), eq, crossovers. I need a volume knob and fader control, windows volume is not the same as a master volume of a headunit.


1. The poineer uses internal ADC analog to digital converter to process the analog sound from the computer to then DSP it to then converter it back down to analog through the decks DAC stage. As it does all other deck sources.

2.yes

3. The outputs are rated at 5volt, the inputs are rated at ~1 volts according to what is typically connected to them, ie a low voltage portable source, an ipod. In home equipment inputs are rated to a max of 2 volts because the sources (ie cd player and such), are not limited by the 5 volt battery that limits portable sources. So they can bump it up a little more.


----------



## MarkZ

JdotP17 said:


> Thanks markz, but without a headunit giving me 6 outputs how can I do Time alignments and crossovers?


Check out that how-to link I posted previously. Alternatively, download foo_dsp_xover and play with it in your home PC. It does crossovers and time alignment (though the time alignment is limited... consider instead matrix mixer or other foobar2000 plugins that do it). You can do all the processing that a HU can do within foobar2000! Or you can use a VST host and plugins to do crossover, EQ, t/a, etc. Lots of options. Check out my build thread too if you want to see some examples.



> In addition the components of the 8 channel giga are poor


Which ones? I posted the DAC. The datasheet is readily available. -92dB THD+N, 112dB dynamic range, etc.

The op amp is a 4580
http://focus.ti.com/lit/ds/symlink/rc4580.pdf

.0005% THD.
Flat freq response out to 30kHz...

And then there's an antialiasing filter and a muting circuit. There's NO other internal circuitry. I own it, I've looked. I drew up the schematics once.

So, there are four components in the signal path. Which of those four components are poor? Or are you just assuming they're poor because you don't like the ESI brand name for whatever reason?


----------



## JdotP17

Thanks all,

I have decieded, as of yesterday, to go with the following setup.


*Laptop - Optical out - External DAC (RCA) - Audison Bitone*

Or if there is little difference between the two DAC's, the simpler setup of

*Laptop - Optical out - Audison Bitone*

The Audison's computer interface is perfect for my laptop, there is the external controller for volume, fader, eq and crossovering on the fly as well as 8 channel output. In additon if I where to use my external DAC I would also have the added benefit of the DACs pre-amp stage to boost any lagging signals with its volume controller.

I think this pretty much caters for all my needs.

Joe


----------



## MarkZ

I think the Bit One is a great choice.

But you really need to try to understand how DACs work. DACs do not enhance the signal. Even the best DAC ever created adds distortion and noise. When you run an additional DAC in series with another (and, by extension, use the ADC of the next stage), you're needlessly taking away from the signal. So, it makes absolutely no sense to convert from digital to analog, then BACK to digital, and then back to analog. Get rid of the first conversion and feed the optical directly into the bit one.


----------



## JdotP17

Cheers Mark, 

Well as I have many DAC's laying around the house I not intending to purchase any more thus I can try both options whilst only needing to purchase the bitone.

I have heard great things about the Bitone's internals so im looking forward to hearing it in person, my only qualm is that it sounds too "digital" what with all its processing and such.

I guess my opition is go Analog with a top quality DAC
or 
Go digital with all the processing I could imagine with a decent quality DAC.

Joe


----------



## JdotP17

I was just thinking earlier today regarding audio signals and the amount of Digital to analog conversions in the audio path, what, of the two following potential audio paths would you choose and why.

1. £5 Mp3 player to Auxillary in of Audison Bitone

2. £1000 DAC connected to another £1000 DAC to Auxillary in of Audison Bitone.

Basically my query is how important is a clean, pure signal as seen in option 1 compared to 3 D/A conversions, but with obviously high quality components in option 2?

Joe


----------



## MarkZ

JdotP17 said:


> I was just thinking earlier today regarding audio signals and the amount of Digital to analog conversions in the audio path, what, of the two following potential audio paths would you choose and why.
> 
> 1. £5 Mp3 player to Auxillary in of Audison Bitone
> 
> 2. £1000 DAC connected to another £1000 DAC to Auxillary in of Audison Bitone.
> 
> Basically my query is how important is a clean, pure signal as seen in option 1 compared to 3 D/A conversions, but with obviously high quality components in option 2?
> 
> Joe


You can determine the answer by looking at the individual DACs and ADCs (don't forget those!) that are used in the path.

When you put these components in series, you're summing the distortion performance, frequency response, and noise attributes of the individual components (actually, you're not exactly _summing_ here, but close enough).

Adding an expensive DAC in series with another DAC cannot improve the signal. It can only detract from it (you can only add distortion and noise by adding components, you can't subtract). A digital bit-perfect signal coming out of a laptop and going directly into the final DAC is always going to better than the same signal first going through a DAC and ADC intermediary.


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## JdotP17

But what happens if the DAC which the bit perfect signal from the laptop is going to is mediocre at best? Where as the best DAC in the world connected to another best DAC in the world would surely sound better than connecting a laptop to an average dac (not takinginto consideration noise issues).

Obviously some DACs sound incredible whereas some sound awful, its all in the internal components, I mean if I connected an mp3 player directly to my amplifier, the fact its a pure signal mean nothing, as the components of the mp3 are going to be poor thus the sound is going to be poor.

P.s I stumbled across a thread arguing about the best headunit to connect to a bitone. What I couldnt understand was, as these headunits dont have an optical out, they are thus using RCA out meaning the headunit is going to a D-A conversion then the DAC in the bitone is going to do a D-A conversion. Why would anyone want to ever pair a headunit up with a bitone?

Joe


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## JdotP17

Ive just found out the Audison Bitone uses 8x - Non oversampling 24bit Wolfson DACs, the same DAC chips I might add that are uses in one of my great sounding DAC's.

Guess I wont need an external DAC in the chain after all. 

Joe


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## MarkZ

JdotP17 said:


> But what happens if the DAC which the bit perfect signal from the laptop is going to is mediocre at best? Where as the best DAC in the world connected to another best DAC in the world would surely sound better than connecting a laptop to an average dac (not takinginto consideration noise issues).


Yup, this is what I said in my last post. If the "bad" DAC exhibits more distortion, noise, and poor FR in comparison to the cascade of two DACs (along with the ADC between them), then the second option is better. This is correct.

My other point was that DAC #1 going into DAC #2 will always perform worse than DAC #2 by itself. This is important because it appeared from your latest diagram that you were considering going optical->cambridge->bitone, whereas you could have just gone optical->bitone. The cambridge would have added nothing of value to that arrangement.



> Obviously some DACs sound incredible whereas some sound awful, its all in the internal components, I mean if I connected an mp3 player directly to my amplifier, the fact its a pure signal mean nothing, as the components of the mp3 are going to be poor thus the sound is going to be poor.


It depends what you mean by "internal components". The performance of most no-frills designs will depend almost entirely on their DAC performance. The DAC is a chip inside the device. For example, the ESI sound card I have uses a DAC which outputs its signal to an op amp and then a muting transistor. The op amp and muting transistor impart pretty much zero distortion/etc. The performance of the card is dominated by the DAC.

The quality of the mp3 player -> amplifier signal you're talking about is going to depend on the mp3 player's DAC. If it has a good DAC, it'll be fine. If it doesn't, it won't. If the mp3 player also shoots it through an internal amplifier and other circuitry, that may degrade things too. (or maybe not, depends on how "clean" that circuitry is).



> P.s I stumbled across a thread arguing about the best headunit to connect to a bitone. What I couldnt understand was, as these headunits dont have an optical out, they are thus using RCA out meaning the headunit is going to a D-A conversion then the DAC in the bitone is going to do a D-A conversion. Why would anyone want to ever pair a headunit up with a bitone?


Haha you asked this question the other day about the MS8. The answer is that the amount of distortion, noise, and frequency response variations we're talking about here are incredibly small compared to the amount of distortion and FR variation produced by the speakers in their environment. So, people usually choose elaborate processors so that they can tame some of these problems. I know you don't subscribe to this school of thought, but lots and lots of people do.



> Ive just found out the Audison Bitone uses 8x - Non oversampling 24bit Wolfson DACs, the same DAC chips I might add that are uses in one of my great sounding DAC's.
> 
> Guess I wont need an external DAC in the chain after all.


Not that you ever did... As long as you had decided to go with the BitOne, you had no choice but to rely on its DAC since it does its processing in the digital domain.


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