nearly finished car pc but interference and no usb hub ?

[hollow]

decided to install the pc in the car this week as the weather has been great

taken my time removed all interior etc to make things easier

brand new cables for everything £88 quids worth

installed pc in boot have an amp in boot for sub and one 4 channel up front for door speakers

connected all earths to one single point ,plus has mobo earth and case earth

all power feed+ connect at same point and direct to battery

no screen interference ,no amp intereference ,checked with other audio source

but pc has loads of interence ,buzzing humming,whining ,usb noise even hums when u move a mouse plugged into usb

just cant find the problem with it

using m2 atx power supply which wont power the amps remote line

and i cannot get the usb hub to work unless its on a 1 metre cable

anything over that and it cannot send ,recieve data ,mouse lights up but wont move ,even with 5v line to hub (belkin hub)
should i buy a new hub or should i buy a usb repeater cable to boost signal level ??

starting to do my head in a little now and to top that my cars engine managment light came on going to cost me 54 quid for a boost valve

[radiotrib]

I have 3metre USB cables, and a simple cheap powered hub up front and it's no problem at all to run DVD (separately powered) touch pad, USB mic plus plug in mouse, kbd and 4gb dongle ... Sometimes having 2 HID's plugged into the same hub/controller can cause issues (like touch screen and mouse). I use a dedicated 3m extension to the touchscreen usb just to keep it away from the rest.

Try moving your devices around. I moved things a lot until it all settled down, and now it all seems to work <me>rush around touching all the wood I can find</me>

My MoBo has 3x2-port controllers, so my touch screen and sound are into one controller, the hub is in the second (Silabs will probably follow if I decide to use it), and the third runs the GPS dongle and a second hub with UMTS and Wifi.

Computer noise .. bus transmission sounds ... tend to be caused by not using a metal or metal lined case and/or shielded cables ... could that be the problem? If it's a wooden box, line it in Baco Foil and see if it helps. Look at the USB cables too. Cheaper ones arent shielded.

Ah .. quick re-read tells me you spent money on good cables and the box must be metal because it's shielded and connected to the mobo. Still .. I'll leave the advice in case someone else reads it and needs to know ...

[Pete]

May be going against the flow here regarding grounding so if I'm talking c***p please ignore me. My experience is as an electronics engineer getting instrumentation to work in noisy industrial applications rather than car installs but the principles should still apply.

With earths it's the connection impedance down to the common ground point that matters most. High earth impedances mean that the noise currents start to look for other routes back to ground, these often being the signal cables which is what causes the problems. High impedances are caused by long cable runs and/or thin cable.

Based on your symptoms my guess would be that ground return for your motherboard is either very long (being routed back to the front of the car?) or fairly thin cable. Have you tried grounding it directly to the chassis (same goes for the amp up front) or running a much thicker ground cable?

It's also possible that this could be causing the USB problems, but only if either the hub or one of the peripherals on it has a ground up at the front of the car?

[2Fast]

No Pete, you are not talking c**p. You have knocked the nail squarely on the head with the high impedances, and it is the cause of most CarPC noise. There is a quick and effective way to resolve it though, and that is with a Ground Loop Isolator between the sound card and the amp. 9 times out of 10 they will completely cure the problem, with no loss to sound quality.

[Pete]

Thanks 2Fast, always a bit hesitant about ground loop isolators though. They're transformer based and I'd imagine that the cheap ones will load the signal lines at low frequencies and cut the high end frequencies. A good quality one should be OK though.

I'm expecting this problem when I get round to my install, the amp (HU) is up front and the PC is at the back. Have been wondering about an electronic ground loop isolator based on instrumentation op-amps, anyone come across anything similar?

[hollow]

thanks for the advice given i have read the forum for weeks before installing looking at all the problems ppl have had and tried to avoid these first time

the ground wire is 6mm and no more than 30 cm long to ground point for pc and 1 amp from there it runs up front to other amp

if i connect the car head unit i had in to the power and rca then there is no noise ,hum works fine ,

so the noise is definately coming from the pc

my brother suggests trying to earth the audio out block on the pc seperately which i will try today , as someone on here stated try getting to the source of the problem before using ground loop isolators .

as for the usb hub it is connected directly to the pc with a 3 metre usb cable, belkin lifetime guarantee, plus the hub is belkin
it outputs to the dvd drive and the upfront auxillary usb port which has nothing plugged in it .
power for the dvd drive is from a seperate source
usb hub is also fed power from the pc via a 5v line
the hub is supposed to light up when recieving/transmitting data but only lights briefly if i plug the usb feed into it .

will be outside today trying to find the cause to these 2 problems

[Pete]

If you unplug the DVD from the hub will it then see other non-earthed peripherals (e.g. mouse, keyboard, memory stick) plugged into that hub?

Sounds like could be the cable up to the front amp. 6mm is pretty good but it would still be worth trying a short earth to the chassis at the front amp?

Edit: Just had a think about this, don't think it's the cable up to the front after all, doesn't fit the symptoms. Believe your brother's right, ground it at the audio outputs. It's could be the impedance of the power supply and wiring inside the PC that's the issue, if it is then grounding at the audio output should fix it.

[Bazmcc]

I had interference problems at the start as well. It turned out to be that the case wasn't earthed well enough. So after earthing the motherboard to the case and the case to the chassis and adding a ground loop isolator I have no interference at all.

I also had lots of USB hub problems.
Here's what solved it. It was an instant fix. Now all my usb stuff at the dash works perfectly.
http://www.maplin.co.uk/Module.aspx?...ender&doy=15m5

[hollow]

hi all

since my last post things have changed slightly

whilst looking into the interference problem i rebuilt the car pc into a slightly larger case so it fits into the side panel better in the boot

fitted 3 ground loop isolators ,front ,rear,sub

added 1 usb repeater cable .

pc works fine now as such and hopefully i am coming to the end of the problems , i did say hopefully

still have still problems with pc getting stuck at bios screen on resume the odd time
slow boot from resume
all interference gone boot little to no sound to sub
no sound to back speakers when playing mp3 from roadrunner but sound on all 4 channels from radio on line in

repeater cable now needed for dvd drive as its not detected by windows

[radiotrib]

If it's a Soundblaster family 5.1 card there are control settings in the Creative software to sort out the sub and 4 channel issues. I'm off for wine and telly right now, but if you want me to tell you my setup I will tomorrow.

[ccsnet]

Originally Posted by radiotrib

If it's a Soundblaster family 5.1 card there are control settings in the Creative software to sort out the sub and 4 channel issues. I'm off for wine and telly right now, but if you want me to tell you my setup I will tomorrow.

Makes a change to the spanish stuff

Terran

[hollow]

cheers radiotrib
nope its not creative its realtek onboard hd audio
the board has front ,rear,centre/sub,side,mic in,line in

and all the jack sockets are configrable to what you want like most boards these days

all the outputs are correct and when you plug the audio in it popsup on screen to select what output you want

will have another play tommorrow , ordered another usb repeater and just incase 2, 3.5mm audio splitters

have found out 1 certain thing with incar pc so annoying when you think you have the hardware sorted another issue just arises

[radiotrib]

A lot of 5.1 cards and PC software only support front speakers for stereo and 5.1 for games/movies. The creative stuff allows you to distribute standard stereo sound to 3 pairs in certain definable ways. I'd be surprised if Realtek doesn't do an equivalent software app.

http://www.redflagdeals.com/forums/s...d.php?t=555823

oogle in "Realtek HD Manager", and download the latest version. The trick is, to install it twice. Once you install it twice, open it from control panel, and enable "sound effects", click "speaker fill",

or

http://www.driverheaven.net/audio-ge...-pls-help.html

I have a cheap set of PC 5.1 speakers hooked up to Realtek onboard sound and had to switch the "Rear Speaker" output to "Side Speakers" in the Realtek control panel to get the rear speakers to work. Might want to give it a try.

[hollow]

righty

have spent the afternoon in the car downloading drivers , winamp plugins etc

got to the stage that winamp no longer runs in roadrunner and the sound is exactly the same as when i started

but wait for it ,drumroll

i did find that if i play audio through media player 11 everything works all 4 speakers plus the sub and they sound so much better alot richer sound

cant mediaplayer be implemented into roadrunner and if so how do i go about it ??

[hollow]

well cheap fix actually free not reall what i hoped for but it works

found out in realtek manager that you can map all the audio outputs to the front speakers

my audio manager doesnt have the fill stereo box but if you click the piccy of the rear speakers ,sub etc the pop up dialog box appears asking you to select which out put i just selected front for all of them

doesnt seem to have the audio quality it did when playing through windows media player and all speakers configured correctly but it works