Line Feedback

2k5f150 · 06-07-2005, 08:30 PM

Just when I thought it was safe,.....
I got my car pc built, software loaded, carnetix configured, screen installed, amp installed, sub installed, lines connected, and then feedback!

The carpc plays fine on its own, the XM plays fine by itself too, but when both the XM Direct and the PC are on the same line, the feedback is unavoidable. I have tried running the RCA jacks off of Y adapters to the amp, and also used the XM Direct through the Mic input as I have no Line In on my Xenarc. I can use the gain on the Mic to control the volume of the feedback, but unless it's muted, it is definatley still audible and until I mute it again I can hear the feedback regardless of the input.

I'm just about out of options, other than giving up on using the XM through the system or trying an external sound card.

All ideas welcome!!!!!

Bugbyte · 06-07-2005, 09:19 PM

You need a line input to the Xenarc. Don't they make a product that uses USB as an input/output device? There's one for the Mac called the iMic by Griffin. They must make one for the PC.

Also, have you looked inside the Xenarc case itself to see if there's an input?

2k5f150 · 06-08-2005, 08:10 AM

A line input would be the ideal solution, but there just isn't one on the standard case. I haven't looked at the board itself, but I'm not sure that I could pull that off. I'm leaning towards the Audigy USB sound card and using the line in for the XM input. Which creates another problem. POWER. I'm using the secondary input from my Carnetix P1900 to power the touchscreen. To run another USB device I'd have to move the screen off the P1900 and reset the jumpers for 5V to power a USB hub and the Audigy.
Would running the screen separately be a cause for concern? I know that Carnetix is coming out with a module to snap into the P1900 that will add the 5V I need, but I need to try to get this wrapped up sooner that the end of the month when it ships. I've got a 2 month old daughter and my wife is having fits about always driving her car when we all go out because of this install.

Bugbyte · 06-08-2005, 09:32 PM

Get this: 5 volt regulator at radio shack. 12 volts and ground in, 5 volts out. Hook that up to your hub.

binary.h4x · 06-08-2005, 10:11 PM

Walmart sells a cigarrette lighter dc-dc power adapter. Comes with a variety of jack sizes too.

2k5f150 · 06-09-2005, 08:34 AM

This problem is getting really annoying! Now I'm noticing interference on the touchscreen in the form of faint scrolling horizontal lines whenever an audio source is engaged. There is background noise as soon as XP loads, and it becomes more pronounced whenever I open an app that will use the sound card.
I did noitice that the screen and pc share a common ground off of the P1900, but the XM is on a separate ground. I also realized that the shop who I had run the power cable to the amp and take apart the interior did not use the power from the dedicated + to the amp and ground to chassis for the Carnetix, but rather pulled power from somewhere under the dash with constant power.