How to: Car Audio on a computer - Overclock.net

pioneerisloud · 11-06-08

Alright, well this was a long shot and it ended up working. So I'll post this as a how to.

Equipment you'll need:

Car Audio Speakers (subwoofers would be the most common)
Car Audio Amplifier (whatever your choice)
Computer power supply with enough amperage on the 12v rail
ATC Fuse holder with wire and appropriate fuse

Steps:

Cut off ALL the wires off the 20/24 pin connector. Make sure they're all REALLY short to ensure that you don't accidentally try to use any of them. Leave the green wire, and the closest black wire (to the green) longer.
Connect the green wire to the black wire. This will provide the power supply with a remote power on (instead of using a motherboard).
Next, cut off all molex, and other power connectors. If they have a 12v and ground line (yellow / black), keep those two wires long...the rest can be cut short.
Connect all 12v (yellow) wires together from the molex connectors.
Connect all ground (black) wires together from the molex connectors.
Install the ATC inline fuse holder on the 12v line. This helps to protect your amplifier...just in case.
Connect the 12v to the + side of the amplifier, and the ground to the - side. Also connect a bridging wire between the 12v and the "REM" on the amplifier. This will give your amplifier a "turn on" signal.
Connect your RCA line level wires....or your speaker line level wires for signal.
Hook up your speakers / subwoofer.
Adjust gains, and you're done!

Things to note:
Keep in mind that computer power supplies are NOT meant for this kind of a load. It will work, but be VERY wary about the amperage.

My particular setup has an MTX Thunder 250.2 2channel amplifier and a Premier 2000SPL subwoofer. I have the amplifier wired to only ONE CHANNEL at a 2ohm load to make 125w RMS power. That is NOTHING for this poor subwoofer, however even this with the gains all the way down is almost drawing too much of a load.

Also....if you connect more than one Power supply in line (the 12v and ground wires connected together), this will provide you with more amperage you can work with (as I've been told). This information is thanks to fellow OCN members....please read on in this thread to find out who.

Pictures are attached for your enjoyment. If requested, I will show more detailed pictures of how this was done, but I think the text is pretty self explanitory.

Disclaimer:
Doing any of these steps may or may not damage equipment. Keep in mind computer PSU's need to have a load on their 3.3 and 5v rails as well, and car audio doesn't do that. Also keep in mind that if the PSU blows, it may or may not take your amplifier with it (hence the fuse....but that was just theory on my part). So if you are to attempt this at home, myself and OCN holds no liability.....use this guide at your own risk! Just because it is working for me, right now, doesn't mean it will continue to work...or that it'll work for you.

Special Thanks To:
(still working on giving credit to those that have brought things to my attention)
a1161979 - Possible damage to audio equipment.
a1161979 - Really good info about Home Theater DIY stuff.
Grim - Possible break down of PSU's, but link more together.
redsunx - Running amps from a battery and battery charger.
Sam1990 - Info about running it straight off a car battery.
shinji2k - Info about 3.3 and 5v rails.

aaronman · 11-06-08

I don't see why it wouldn't work. 12VDC is 12VDC as far as I'm concerned.

But there's probably better 12V power sources such as a simple AC to DC power transformer.

G|F.E.A.D|Killa · 11-06-08

i have though about this too. you might need more amps on the 12v rail.

-=sT3V3=- · 11-06-08

I have done it before, I used AT PSU's, 3 of them, 200W each, i inked them all together to power my AudioBank 1400W amp & 2 JBL GTX 8" it worked, but I made a PSU rather with a 120va 12V transformer(took off a few windings to increase the Voltage to 15V)
Then use a 20 A bridge rectifier to get me DC...
The Amp could draw 25amps continious without shutting down, and is still functional...

pioneerisloud · 11-06-08

Quote:

Originally Posted by G|F.E.A.D|Killa

i have though about this too. you might need more amps on the 12v rail.

Well it worked! Let me explain how it worked.

Obviously 12VDC is 12VDC...however there are amperage issues at stake here too...ESPECIALLY with a Generic 450w PSU.

I went stereo (Philips Home Theater) to stock subwoofer pre-amp. Pre-Amp speaker out to the Speaker Inputs on the car amplifier (instead of running a REALLY long RCA cable...and this gives me two crossovers to ensure nothing above 80Hz goes to my precious).

Power Wise:
Cut the entire 20 pin plug off, and twisted the green wire and a ground wire together (to turn on the PSU). All other 20 pin plugs I shortened as far as I could.

Then I clipped off ALL molex connectors at the very first one per line. I used 3 yellow wires (12v), and 3 black wires (ground). I then connected the 3 yellows into a standard ATC fuse holder, and supplied it with a 15a fuse.

I then connected the other end of the fuse holder into my +BATT on the amplifier. The 3 twisted together grounds went to -GRD on the amplifier. For a remote turn on wire, I just used one of my many spare PSU wires and bridged the +BATT to the +REM on the amplifier.

Now.....this particular PSU only had a MAXIMUM of 19a available on the 12v rail. This particular amplifier can draw UP TO 40a on it. This posses a problem! I just ran it off one channel instead of bridged mono (like it was in the car). I have a DVC subwoofer, so I was stuck with either 2 or 8ohms....and I chose 2ohms. This gave me 125w RMS power off that one channel. Which ROUGHLY equates out to about 10-13a.

So....I'm well within the amperage limits of the PSU, even though its old.

By the way....I have BOTH gains ALL THE WAY DOWN....and this sucker is still rattling ALL OF THE WALLS throughout my entire apartment!!! Soooo much louder than my stock subwoofer.

This particular setup now probably rivals the loudest ACTUAL computer speaker setup money can buy. The only thing actual computer speakers has on me now is true 5.1+ surround sound. I only have Dolby Prologic (whoopty doo).

Grim · 11-06-08

Done it MANY times Pioneer.

Congrats on your success.

You may find that it wears your PSU though.
In cases where the PSU just cant cope over the longrun and the components break down - you'll notice the amps (and hence the audio) chipping out momentarily.
So if that happens, you know its a sign! lol.

The AMP from time ago probably smoked itself because the diode's in the charger gave out, (because it couldnt cope with the load) and started leaking AC current through!

The PSU shouldnt do that. I doubt it would.

What friend there above mentioned is a good Idea. Ive used it in other instances.

Pair up 2 generic PSUs - you'll have twice the wattage.

MAN, if you get 3 of them, I bet you'll be able to run all channels of the AMP

(though thats asking for a lot

)

Whats your speaker setup like Pioneer? ^_^

pioneerisloud · 11-06-08

Here's a picture of the subwoofer from the trunk of my car.

It is running off an MTX Thunder 250w 2 channel amplifier. Only one channel, with a 2ohm load. The left channel is NOT being used on the amplifier at all...keep power consumption down.

Grim · 11-06-08

ooo.

nice looking sub.

So is its currently running in the car then?
dont know where I got the impression that you were using it for a PC sound system.

So what you doin' - just running the mid/tweets straight from the car radio?

pioneerisloud · 11-07-08

Quote:

Originally Posted by Grim

ooo.

nice looking sub.

So is its currently running in the car then?
dont know where I got the impression that you were using it for a PC sound system.

So what you doin' - just running the mid/tweets straight from the car radio?

Car now just has stock radio. That subwoofer and the MTX 250w 2 channel amp are in my office hooked to my Home Theater / PC sound system. I WOULD have used my Alpine 600w Monoblock amp to push it in here....BUT, I really don't think that Generic 450w PSU will do the trick for that one, lol.

You had it right.....I moved it FROM the car INTO the PC gaming room

.

Grim · 11-07-08

zeen zeen. nice
SO, what you have playing Mid/Top end in the office?

Should sound monstrous with that sub.

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How to: Car Audio on a computer

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