Ok, I don't know much about car audio, I just let my ears decide whats good enough for me. I have Sony 6.75" 4 ohm 2 way speakers in the front and Sony 6 x 9" 4 ohm 3 way speakers in the rear. I plan on buying a 4 channel amp soon. I don't know which brand yet but it will have to be 4 channel and have built in front and rear crossovers. My question is, I keep reading that such and such amp is 50 watts x 4 at 4 ohms and 100 watts x 4 at 2 ohms. With my rig, will I be running the amp at 4 or 2 ohms??

Thanks in advance!

 

If you use 1 4ch amp to power your front and rear speakers,it will be 4 ohms fot the front and rear.

Lets say for example you were going to have a total of 4 speakers in the front of the car.2 left and 2 right.All 4 speakers are rated at 4ohms.If you wired 2 speakers to each other in parallel(for each side)then connect that to the respective amp channel,then each channel would be 2 ohms.This is because when you wire speakers of a particular impeadance to each other in parallel,the total impeadance drops in half.When this happens,the amplifier is now able to produce twice the power that it can in a 4ohm load.

Now,if you had 2 4 ohm speakers and wired them to each other in series,the total impeadance adds.So in this case you would have an 8 ohm load on the amplifier.Car stereo amps are not rated to output power into an 8 ohm load,so the amount of power will be half that of a 4 ohm load.

Hope I was able to clear things up a bit. smile.gif

 

You cleared things up a little more me, but now I have more questions. When wired parallel, are all of the controls the same as if wired normally. Will I h ave fade controls, and still be able to cross over front and rear channels at different ranges?? Also, without diagrams, how do you wire my 4 ohm speakers to get the 2 ohm load, and how are the wired to the amp?

Thanks in advance.

 

I was just giving you an example of parallel and series.For your application,you should keep the 2 front speakers on the front half of the 4ch amp,and the rear speakers on the rear half of the amp.That way you have fade control and you can xover the front/rear differently.

 

But then I won't be able to bridge it down to 2 ohms to unlock my amps potential??

 

you do NOT want to run your mid-highs at two ohms....for one if speakers are 4 ohm single voice coil...which they are...you will fry the coil....and 2 ohm operation has a greater range of distortion...and reading what speakers you have you dont want them to distort anymore then they already are....2 ohm loads should only be put on subs!

 

I agree with what ONLY1DB has to say,with one exception.You won't blow the voice coil as long as half of the 2ohm output is what each speaker can handle.In other words, if the amp puts out 100 Wrms into a 2 ohm load and each of the 2 paralleled speakers can handle 50Wrms,then there is no trouble.


ALLBLACKTIBBY...........Just connect the fronts to the front and the rears to the rear.This is the best and simpliest way to do it.

I was just trying to explain to you some things about speaker impeadance and the way the amp sees it.

One recommendation though..............why not disregard the use of rear speakers.Then you could bridge the 2 rear channels of the 4ch amp and use that for a sub.The amp you are talking about should be rated for 2ooWrms,bridged.That is a pretty decent amount of power for one sub.

 

I already have a nice Alpine V12 mono sub amp pushing an Alpine s10 sub. I just need an amp so my mids and highs can keep up with the sub and not distort. The sub I have can really pound, but I have the gain turned down on the amp, and the sub output control on the deck turned down in order to be able to hear my mids and highs. Even after all of that I still cannot hear a great range of tone in my door speakers, so I am assuming I need to amp those speakers. I would ditch the Sonys and go with something else, but they were a gift from my wife and I was VERY happy with them before I got the sub.

BTW, the speakers are rated at 140 watts.....can't remember if that's peak or RMS. My original plan was to get an amp that put out 100 x 4 at 2 ohms.

[ March 30, 2003, 03:15 PM: Message edited by: AllBlackTibby ]

 

Oh!!! Let me clarify something.What you are talking about is not bridging.You are talking about a 2ohm stereo load.Bridging is taking 2 stereo channels and making it 1ch mono.

Example:50wrms x 4ch's @ 4ohms
100wrms x 4ch's @ 2ohms
200wrms x 2ch's bridged

Most amps only want to see a 4 ohm total load when bridged.This is because internally,the amp is 'seeing' that 4ohm bridged load as 2ohms.

Amplifiers that can handle a 1 ohm stereo load,will handle a 2ohm bridged load............make sense??

 

ALLBLACKTIBBY..............

It was just a recommendation.I forgot that you are using a V12 mono block.

Yeah,just hook the front/rear respectively.


What is the low pass xover point you are currently using for your sub?? What freq and slope?