Need help choosing what Audio Setup to use for my CarPC

diosagain · 02-23-2007, 12:48 AM

I am currently in the process of fabricating/building my CarPC. I pretty much have everything done as far as the computer goes. Its time for me to purchase an amp and whatever else I need to achieve decent sound quality directly from my motherboard. Some background I am using the new Jetway 2GHZ Mini-ATX motherboard with the M2-ATX power supply. The motherboard has Spidf out and you can also change the three 3.5 jacks to work with 6 channel output. I am a long time computer/home theater builder but when it comes to car audio I am pretty much a noob. I mean home theater amps, every speaker has its own input. None of this bridged stuff.

My question is basically what Car amp should I buy if i am going to leave my current 4 factory speakers in my car. Should I upgrade these factory speakers and maybe add two tweeters? If I add tweeters then where should they go so it can still look factory? Should I buy a Sub and a separate amp to power it? Do I really need a sub? I mean I don't want anything crazy just good enough to watch movies in my car. Should I buy an AMP with SPDIF input so I can utilize the SPDIF output on my motherboard? Or should use the 4 channel output feature on the mother board. Or should I just use the 2 channel output using the line out on the motherboard. Also, if I plug the 3.5 to RCA out of just the line out into the AMP. How do I get that to play on all the speakers if I use a 4 channel amp? Or would I only need a 2 channel amp if I am only going to use the line out to RCA, and if i do that how do I connect the 4 factory speakers to a two channel amp? Crazy, because I really build computers all the time and set up home theaters all the time, but have no clue how car audio amps work.

Also, I took out my factory radio and have some questions about these plugs:

I know the one on the left is the factory wire harness, but do I need any of these wires if I am going with no head-unit and wiring my M2-ATX directly to the battery? Also, if I am installing a AMP under my passenger seat what wires in this harness would I need if any? I know they all have a purpose like they are speakers and stuff but I am don't know if I need any of them. I know the AMP on/off switch is wired directly to the M2-ATX psu.

Also, the one on the right. Is the yellow wire the one that is going to my Ignition? Also, is the black wire with it the Ground going to the Ignition? If so I guess I can use that to connect to 5v ignition switch on my M2-ATX.

Any help at all on how to wire my Car audio and what hardware to buy for my CarPC would be greatly appreciated. As you can see I desperately need it.

pRoFiT · 02-23-2007, 01:38 AM

try this thread first for answers

http://www.mp3car.com/vbulletin/showthread.php?t=32430

Then post your next question

diosagain · 02-25-2007, 05:07 AM

OK, I have done the research and I am going to choose a pheniox gold 4 channel amp with 2 pairs for pheonix gold 5x7 speakers. I think this will be enough for my truck to sound good enough. I think if I want a sub down the road I can always just opt for one then. This still doesn't leaave me with my first question. Is that yellow wire in my first post the ignition switch? I was going over the directions of my M2-ATX and thats the only wire I am having trouble locating. I know its either in that factory wire hireness somewhere or its the yellow one to the right. Also if it is the yellow one then what do I do with the black ground wire. I don't wire that to the M2-ATX power supply. Any help would be greatly appreciated.

diosagain · 02-25-2007, 05:13 AM

Also, do I need a DAC inbetween the computer and the car amps? From what I have read they say it make a word of different. If someone who actually knows can help me out that would be great. I am basically up to the last step of the CarPC build and I am afraid its the part I know the least about. Car Audio....

This is the amp:

Pheonix Gold OCTANE-R 5.0:4
----------------------------
• 4 channel power amplifier
• 12dB HP/LP variable crossovers
• Full range aux output
• Dimensions: 13.75L x 10.875W x 2.25H
80W x 4 (4 ohm stereo)
250W x 2(4 ohm bridged)

Speakers:
Phoenix_Gold R57.0C Octane-R 5x7" 120W Coaxial Speakers
Features:
Octane-R Coaxial Speakers
Angled 15mm Blue Mylar Tweeter Diaphragm
Plated Aluminum Polypropylene Cone Material is Precisely Injection Molded to be Very Light and Rigid for Excellent Signal Tracking
Optimized Magnet/Motor Structures Result in High Efficiency and Clarity
Advanced Rubber Butyl Rubber Surround is More Rugged than Foam; Resists Moisture and UV, and is Extremely Well Damped
Flat Linear Roll Spider Reduces Distortion and Provides Maximum Voice Coil Centering
Rigid Powder Coated Steel Frame
Multi-Terminals Provided for Optional Performance Crossover
Standard Mounting Sizes and Bolt Patterns
Specifications:
Power Handling (Peak/RMS): 120W / 60W
Frequency Response: 65Hz-20kHz
Impendance: 4 ohm
Sensitivity: 90dB
Mounting Depth: 2 3/10"
Mounting Diam.: 5"x7 1/8"

moto_123 · 02-26-2007, 07:43 PM

if you are using the headphone jack on the computer, converting that using a splitter into a pair of RCA wires, then running the RCA straight into the low input for the amp......no you don't need a DAC. the headphone jack outputs an analog signal. this is what I have been using in my car for quite a while, and it seems to sound fine.

if you get into really high end speakers or if your signal is going a very long distance, that is when you may want to consider running a digital signal either to a DAC or to an amp with an integrated DAC inside it. Wires for that could be a good single RCA or optical.

AceX · 02-27-2007, 07:32 PM

^^^Ditto

You shouldn't need a DAC for what you're going to be running. The DAC would provide a higher quality signal, but with the PG speakers that you are putting in, you won't be able to tell hardly at all.

If you ever upgrade to a high end component set like MB Quarts or Boston Accustics, then you might want to switch over, but even then, you might not notice a big difference.

Also, are you going to be adding a sub-woofer?

durwood · 02-28-2007, 07:05 AM

Quote: Originally Posted by diosagain

OK, I have done the research and I am going to choose a pheniox gold 4 channel amp with 2 pairs for pheonix gold 5x7 speakers. I think this will be enough for my truck to sound good enough. I think if I want a sub down the road I can always just opt for one then. This still doesn't leaave me with my first question. Is that yellow wire in my first post the ignition switch? I was going over the directions of my M2-ATX and thats the only wire I am having trouble locating. I know its either in that factory wire hireness somewhere or its the yellow one to the right. Also if it is the yellow one then what do I do with the black ground wire. I don't wire that to the M2-ATX power supply. Any help would be greatly appreciated.

Two ways to figure out which wires are what

1) Use a multimeter and test the voltage coming out of each wire.
2) Buy a wiring harness for an aftermarket radio and the yellow wire from that will be 12V constant and Red would be 12V switched. I highly doubt the gauge of wire is large enough though for powering you PSU. Use a distribution block and use the power from the wire you run to your amp to also power the PSU. That is my recommendation. You could use the 12V swtiched from the headunit though.

Check out the Wiki and FAQ to FAQ for the basics.