# thinking about a car PC



## skittlesRgood (Oct 11, 2010)

I am completely new to making a car PC but i am sick and tired of the aftermarket DD HUs that always have some crippling flaw. so i wanted to find out if i can have everything i want in a car pc. hopefully you guys can help me out with this.

things I care about:
Voice control (artists, bluetooth calls, navigation control)
navigation (good navigation)
ipod/iphone compatibility
bluetooth for making calls (dont use it for music)
great sound quality leading into my MS-8
dedicated subwoofer output
very fast boot up times. i have SSDs and some nice CPUs. think i have a quad core 1.7ghz i can use.
steering wheel controls


is it possible to get all of that in a car PC?
thanks guys


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## mda185 (Dec 14, 2006)

skittlesRgood said:


> I am completely new to making a car PC but i am sick and tired of the aftermarket DD HUs that always have some crippling flaw. so i wanted to find out if i can have everything i want in a car pc. hopefully you guys can help me out with this.
> 
> things I care about:
> Voice control (artists, bluetooth calls, navigation control)
> ...


It is possible to get all of the above with the exception of good bluetooth handling of phone calls and voice activated dialing. I have been playing around with Ride Runner and Centrafuse for years without getting either one to do this 100% reliably. I don't like the fact that Centrafuse folks don't tell you this before you purchase their front end software. Navigation has gotten worse since Garmin Mobile PC software was discontinued. That worked well with both RR and Centrafuse front end software. Centrafuse is rolling out an improved navigation capability but I don't know anyone that has used it yet. Their old nav software left a lot to be desired. 

Getting great sound quality is only possible if you build something based on a micro-atx or larger motherboard with PCI slots or use a high quality USB DAC or USB soundcard. If you build something with PCI slots, there are multiple choices in great sound cards. There are posts in this forum that will give you more details on what works. Going the USB route, you want to look for a DAC or sound card with decent voltage output. Many of them peak at 1 volt RMS and that is not really what you want in a mobile audio environment. Look for something that can do at least 2 volts rms. Pro audio USB equipment usually can meet this spec with ease. 

Dedicated subwoofer ouput is only going to be possible with a PCI sound card that has multi channel capability and with PC software that can take advantage of this. It is possible but you will have to spend a lot of time learning about the software and invest significant money. There are no easy turnkey solutions. I decided not to go this route and just purchased a good 2 channel USB sound card from Roland. It is a Cakewalk UA-1G and is commonly found for < $100. I run that signal into an old school 4.1i analog preamp made by Audio Control. I take the signal out of the 4.1i and run that into a Zapco 6 channel dsp unit. I have been playing around with different amps and do not have a clear favorite. I tend to prefer old school Soundstream equipment but am looking for something smaller with decent SQ. 

Steering wheel controls are possible but I have not explored how to do that. I drive a 95 BMW wagon that predates that feature. 

Bottom line for Car PCs right now is that achieving great SQ is possible but takes a lot of extra effort that may be better spent on getting your speaker installs to be the best they can be. That is the route I am going down and I just bought outboard equipment to handle the crossovers and signal processing. Bluetooth phone control and hands free talking is not reliable yet and may never be with a Windows operating system. Navigation is great with Garmin Mobile PC software but there are no future releases and map updates coming. I have not seen a good alternative yet. Biggest benefit I find with mobile PC is ability to have a large music library in flac format instead of MP3.


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## MarkZ (Dec 5, 2005)

mda185 said:


> Going the USB route, you want to look for a DAC or sound card with decent voltage output. Many of them peak at 1 volt RMS and that is not really what you want in a mobile audio environment.


I have no problem with mine which peaks at a volt or less. I don't really see the issue.



> Dedicated subwoofer ouput is only going to be possible with a PCI sound card that has multi channel capability and with PC software that can take advantage of this. It is possible but you will have to spend a lot of time learning about the software and invest significant money. There are no easy turnkey solutions. I decided not to go this route and just purchased a good 2 channel USB sound card from Roland. It is a Cakewalk UA-1G and is commonly found for < $100. I run that signal into an old school 4.1i analog preamp made by Audio Control. I take the signal out of the 4.1i and run that into a Zapco 6 channel dsp unit. I have been playing around with different amps and do not have a clear favorite. I tend to prefer old school Soundstream equipment but am looking for something smaller with decent SQ.
> 
> Steering wheel controls are possible but I have not explored how to do that. I drive a 95 BMW wagon that predates that feature.
> 
> Bottom line for Car PCs right now is that achieving great SQ is possible but takes a lot of extra effort that may be better spent on getting your speaker installs to be the best they can be. That is the route I am going down and I just bought outboard equipment to handle the crossovers and signal processing. Bluetooth phone control and hands free talking is not reliable yet and may never be with a Windows operating system. Navigation is great with Garmin Mobile PC software but there are no future releases and map updates coming. I have not seen a good alternative yet. Biggest benefit I find with mobile PC is ability to have a large music library in flac format instead of MP3.


Lots of people do just fine with car PC SQ. I don't know what you mean.


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## mda185 (Dec 14, 2006)

MarkZ said:


> I have no problem with mine which peaks at a volt or less. I don't really see the issue.
> 
> 
> 
> Lots of people do just fine with car PC SQ. I don't know what you mean.


Maybe your car has a quieter electrical environment than I am used to. A 1 volt rms output is much more likely to be affected by electromagnetic interference in a mobile environment. Cars like my BMW with rear mounted batteries have issues with radiated electromagnetic fields that can and do get into audio preamp cables running from front to rear of car. The hotter the preamp voltage output level, the easier it is to mitigate this problem. Proper grounding techniques and twisted pair cabling can help also but that is beyond the scope of the OP's questions. 

I am confused by your last statement. Lots of people do just fine with what car PC SQ? Are you talking about sophisticated installs with VSTs, multi-channel sound cards, and good signal processing software or are you talking about basic sound card outputs from a garden variety motherboard sound chip? Yes, I believe you can get very good SQ from a car PC but not if you are trying to use typical low quality sound chips or spdif out on the motherboards. I am a EE with many years experience in dsp for audio and wireless applications and I still find it simpler and easier to use a decent quality 2 channel analog output from my car PC and external signal processing devices. 

I also do not like the SQ one gets with a front end like Centrafuse when it is using the standard Windows mixer. I can clearly hear a difference using Ride Runner, ASIO drivers, and Foobar. When I asked the Centerafuse folks in their forum why they did not develop the ability for their front end to work with better SQ drivers and hardware, they said I represented a very small minority of their customer base and this was not a high priority. YMMV but this is my opinion based on tinkering with home and mobile audio systems and building my own PCs since 1990.


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## t3sn4f2 (Jan 3, 2007)

mda185 said:


> Maybe your car has a quieter electrical environment than I am used to. A 1 volt rms output is much more likely to be affected by electromagnetic interference in a mobile environment. Cars like my BMW with rear mounted batteries have issues with radiated electromagnetic fields that can and do get into audio preamp cables running from front to rear of car. The hotter the preamp voltage output level, the easier it is to mitigate this problem. Proper grounding techniques and twisted pair cabling can help also but that is beyond the scope of the OP's questions.
> 
> I am confused by your last statement. Lots of people do just fine with what car PC SQ? Are you talking about sophisticated installs with VSTs, multi-channel sound cards, and good signal processing software or are you talking about basic sound card outputs from a garden variety motherboard sound chip? Yes, I believe you can get very good SQ from a car PC but not if you are trying to use typical low quality sound chips or spdif out on the motherboards. I am a EE with many years experience in dsp for audio and wireless applications and I still find it simpler and easier to use a decent quality 2 channel analog output from my car PC and external signal processing devices.
> 
> I also do not like the SQ one gets with a front end like Centrafuse when it is using the standard Windows mixer. I can clearly hear a difference using Ride Runner, ASIO drivers, and Foobar. When I asked the Centerafuse folks in their forum why they did not develop the ability for their front end to work with better SQ drivers and hardware, they said I represented a very small minority of their customer base and this was not a high priority. YMMV but this is my opinion based on tinkering with home and mobile audio systems and building my own PCs since 1990.


There isn't a need for ASIO when it comes to playback without processing. Windows7 and a driverless USB soundcard has the same quality as an ASIO specific output with aftermarket drivers. And internal cards are more then not going to come with drivers that replace any windows sound architecture and result in WDM identical in quality to ASIO outputs (EMU-0404PCI WDM vs. ASIO measurements). And that is only a concern if using XP. Below are extensive measurements of a driver less USB soundcard (ODAC). You can see it works as it should and ASIO would not improve on it.

NwAvGuy: ODAC Released 

NwAvGuy: ODAC May Update

By the way, for anyone curious about it. It is $100 IIRC, has a verifying 2 volt rms output yet is USB powered, and has been verified to be acoustically transparent via extensive measurements and blind listening session. IE it sounds the same as even a highly regarded Benchmark DAC1. 

The only issue I could see with it is that there isn't any USB ground isolation so maybe that could result in a possibility of ground loop when using it in a car audio app. Although, that type of design is common and you aren't going to find that feature in hardly anything out there. The only one I know that is completely isolated is the Cetrance DACmini CX.


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## EriCCirE (Apr 14, 2010)

I always thought it would be neat to have the hvac controls integrated. Maybe the obd plugged in so you can have custom gauges and readouts. What about a HUD, carputer ideas are endless.


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## MarkZ (Dec 5, 2005)

mda185 said:


> Maybe your car has a quieter electrical environment than I am used to. A 1 volt rms output is much more likely to be affected by electromagnetic interference in a mobile environment. Cars like my BMW with rear mounted batteries have issues with radiated electromagnetic fields that can and do get into audio preamp cables running from front to rear of car. The hotter the preamp voltage output level, the easier it is to mitigate this problem. Proper grounding techniques and twisted pair cabling can help also but that is beyond the scope of the OP's questions.


Maybe. I don't run front to rear, but in the past I ran low voltage HUs front to rear with no induction issues. My battery is mounted in the trunk, and my current car PC setup runs the RCAs directly across it.  No noise. IME, a lot of the noise that people attribute to induced noise is really a ground loop. Which I admit can be an occasional problem with car PCs, although it's largely independent of signal voltage.

I'm not saying inducing noise is impossible. It's clearly not, especially in the presence of certain class D amps, some modules, and failing devices (bad batteries, bad alternators). But IMO it's the exception rather than the rule.



> I am confused by your last statement. Lots of people do just fine with what car PC SQ? Are you talking about sophisticated installs with VSTs, multi-channel sound cards, and good signal processing software or are you talking about basic sound card outputs from a garden variety motherboard sound chip? Yes, I believe you can get very good SQ from a car PC but not if you are trying to use typical low quality sound chips or spdif out on the motherboards. I am a EE with many years experience in dsp for audio and wireless applications and I still find it simpler and easier to use a decent quality 2 channel analog output from my car PC and external signal processing devices.


The only problem I've had in the past with onboard sound is that it can promote nasty ground loops, depending on the power supply you use and isolation. I've actually had better luck with USB than with PCI in that regard. I'm not exactly sure why, but I have some ideas.

I use a cheap multichannel USB audio device now, using ASIO, and get good results. IME, the key is to make sure you have the proper drivers, otherwise you run into issues that sound like buffer problems and stuttering. By "cheap", I mean it's using the akm ak4358vq and some basic op amp I forget which.



> I also do not like the SQ one gets with a front end like Centrafuse when it is using the standard Windows mixer. I can clearly hear a difference using Ride Runner, ASIO drivers, and Foobar. When I asked the Centerafuse folks in their forum why they did not develop the ability for their front end to work with better SQ drivers and hardware, they said I represented a very small minority of their customer base and this was not a high priority. YMMV but this is my opinion based on tinkering with home and mobile audio systems and building my own PCs since 1990.


Yeah, I don't use Centrafuse because I prefer foobar2000 for ASIO/KS (presently using ASIO). You can also do some things in foobar2000 like upsampling which has some usefulness on the VST end of things (if your plugins support higher sampling rates), although I'd like to upgrade my USB sound card to something that supports 96kHz so I can harness this feature in its entirety. But that's mostly to improve CPU utilization rather than "SQ".

Anyway, my point is that you can do this stuff for cheap, which is where my opinion seems to diverge from yours.


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## MarkZ (Dec 5, 2005)

t3sn4f2 said:


> By the way, for anyone curious about it. It is $100 IIRC, has a verifying 2 volt rms output yet is USB powered, and has been verified to be acoustically transparent via extensive measurements and blind listening session. IE it sounds the same as even a highly regarded Benchmark DAC1.
> 
> The only issue I could see with it is that there isn't any USB ground isolation so maybe that could result in a possibility of ground loop when using it in a car audio app. Although, that type of design is common and you aren't going to find that feature in hardly anything out there. The only one I know that is completely isolated is the Cetrance DACmini CX.


And the other issue is that it's only 2 channel, making it practically worthless for car audio. 

We had this discussion elsewhere.


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## t3sn4f2 (Jan 3, 2007)

MarkZ said:


> And the other issue is that it's only 2 channel, making it practically worthless for car audio.
> 
> We had this discussion elsewhere.


I weemember

That's more of a lacking feature than an issue though. 

I can see potential for it when the Windows tablets start coming out. They are sure to have enough juice in the USB to power the ODAC. Could put the CarPC hardware market out of business. Buy a sunlight readable 7-?" screen (ie tablet) and get a PC for free.


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## MarkZ (Dec 5, 2005)

But you can't do PC processing with only two channels. You need at least a 6 channel solution for most people.


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## whoever (Nov 21, 2008)

I use 4 behringer UCA202's with no problem on my CarPC setup.


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