Thread: FAQ: Connecting your Car PC's Power and Speakers

Originally Posted by jasondavis

heres a question, I have 0 gauge wire running to the rear of my truck for my amps, could I tap into this for power to my 150w Opus? If I can, how would I go about doing it? sorry for the basic but important question

I would say just take the 12v+ from your opus and put it on a wire going to your amp. I plan to just unscrew one of the amp wires from the fuse block and put my PSU wire in there with it. But I am a newbie too and actually have a remote power on/off control.... no fancy startup/shutdown controllers here.

273BeLow - I wouldn't advise people to wire 2 speakers into one chanel of your amplifier. The problem with doing this is that wiring two speakers in parallell with each other like that reduces their impedance which inturn results in higher current through the amplifier.

Most amplifieres are designed to handle ONE 4 ohm speaker on each chanel - putting the two speakers in parallel will reduce the equivalent impedance of your speakers to 2 ohms and you risk overheating your amplifier - possibly invalidating its warranty (not 100% sure about that) - and u loose a good amount of your output power inside the amplifier as well.

If you are not putting much power through your speakers then i wouldn't worry about it too much just be aware that its not the best thing to do to your amplifier. If you really want more speakers i suggest buying a better amp.

Spuzzdawg

Some people think they have it down pat...

RED is NOT ALWAYS 12v

eg...

older Ford Models:


12v - Green/ Yellow
Switch- BLACK/pnk
Ground- BIG RED WIRE

--CROSS THESE WIRES AND SAY GOODBYE TO YOUR PROJECT---

2 things to add,

Im running my m2-ATX off an OEM 20 amp radio circuit in my dash with no issue at all. (been running good for 6 months now)

Im also running a 2 channel amp off of another OEM 20 amp circuit. I am running 4 speakers off of this amp without an issue either. I however wired my speakers in series NOT parallel because the OEM speakers are 4 ohms each. By wiring them in series im putting an 8ohm load across each speaker channel so my amp will not run hot. If you put them in parallel you are dropping the load to 2 ohms and most amps are not 2 ohm stable on each channel. Permit me to elaborate with this cheesy paint render

Originally Posted by 273BeLow

this might be handy. If you want to cheaply wire four speakers up to a two channel amp then simpy run four wires (two sets of twin) from your amp to the front and then have a Left +/- and a Right +/- then wire the two left hand speakers to one set and the two right hand speakers to the other thus:



sorry if it's obvious but it saved on running lots of cables.

thats just asking for disaster... wire speakers in SERIES not parallel...

Originally Posted by spuzzdawg

273BeLow - I wouldn't advise people to wire 2 speakers into one chanel of your amplifier. The problem with doing this is that wiring two speakers in parallell with each other like that reduces their impedance which inturn results in higher current through the amplifier.

hu?

yes, this is true, but why wouldn't you advise people to run an amp at 2 ohm? nearly every amp on the market is 2 ohm stereo stable now a days.

There is a lot of misinformation in this thread, like here for instance....

Most amplifieres are designed to handle ONE 4 ohm speaker on each chanel - putting the two speakers in parallel will reduce the equivalent impedance of your speakers to 2 ohms and you risk overheating your amplifier - possibly invalidating its warranty (not 100% sure about that) - and u loose a good amount of your output power inside the amplifier as well.

no - most amps now a days are stable at 2 ohm stereo, as I stated above.

If the amp is stable at that ohm load, you may increase your distortion, but because you are now putting out more power and probably running double the cone area, you are able to turn your gains DOWN due to more output period.

you would NOT void your warranty by running an amp at a rated impedance level.

If the amp specs say the amp will do it, why would it void your warranty?

Originally Posted by jnetn99

Some people think they have it down pat...

RED is NOT ALWAYS 12v

eg...

older Ford Models:


12v - Green/ Yellow
Switch- BLACK/pnk
Ground- BIG RED WIRE

--CROSS THESE WIRES AND SAY GOODBYE TO YOUR PROJECT---

ditto! red is NOT always positive....there's those blanket statements again I keep seeing....blanket statements are baaaaaad

Originally Posted by blk02si

Im also running a 2 channel amp off of another OEM 20 amp circuit. I am running 4 speakers off of this amp without an issue either.

SINCE you are wiring your amp in series, then you probably aren't pulling more than 10 amps, and in this case this is fine. However, this can be a dangerous post for those who will be running their amps at 4 ohm or 2 ohm. In general, this is not a good idea.

Yes, that's one of those blanket statements I hate so much, but it's one that's true.

If you put them in parallel you are dropping the load to 2 ohms and most amps are not 2 ohm stable on each channel. Permit me to elaborate with this cheesy paint render

this is incorrect.

I'm not sure where the people in this thread are getting that modern amplifiers are not 2 ohm stereo stable, but it's absolutely not correct.

Modern amplifiers are almost always 2 ohm stereo stable.

re: your paint renderings:

the first one: "not good unless you have a 2 ohm stable amp"

correct, but again, MOST modern amplifiers are 2 ohm stereo stable. I'm worried that someone will read that and freak out because they aren't well educated in the car audio world. They will see it and think that they are all wrong, when in fact they aren't.

use this as an example:

someone goes out to a big box retailer and buys a 50 x 2 amp @ 4 ohms to power 4 speakers.

they wire it up in series (8 ohms), you get 25watts x 2 @ 8 ohms. Meaning each speaker gets 12.5 watts. Now you have to turn up the gains to get the expected volume output out of those speakers, meaning you're more likely to run into clipping and distortion because your gains are up so high. When if you had run them in parallel to get 2 ohms out of them, you're running at 100 x 2 @ 2 ohms at the amp, meaning 50 watts per speaker, meaning gains lower to get the same amount of volume. Meaning, less likely to have clipping and / or distortion. Yes, distortion at lower impedances will be higher, really good ears don't even hear 5% distortion. Yes at 2 ohms the amp will pull more current, and yes at 2 ohms you need to beef up your wire and grounds, but you get more out of your amp.

The root cause of the issue can be solved by buying the proper equipment for your application, if you have 4 speakers, buy a 4 channel amplifier.

re: your second image: series allowing you to turn gain up without risking clipping or blowing out a channel.

this is along the same lines of what I have already said.

if you're higher impedance you're less power, thus you HAVE to turn the gain up to get the needed power output.

Originally Posted by mike6789

thats just asking for disaster... wire speakers in SERIES not parallel...

why do you say this?

how is this a disaster?

again, I'm lost as to why people in this thread think that parallel is the debbil??

again, most amps are 2 ohm stereo stable...it should be fine!