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Discussion Starter #1
I need help figuring out how to run 8 speakers on a 4 channel amp. Two speakers per channel right? The front two channels would be a 3 ohm 6.5 coaxial and an 8 ohm 3.5 full-range driver. The back two channels will be an 8 ohm 6.5 driver and a 4 ohm tweeter. I don't know how to calculate the overall resistance between the speakers in the system or even how to wire them to be compatible with my 2 ohm stable amp. Any help would be greatly appreciated.
 

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I need help figuring out how to run 8 speakers on a 4 channel amp. Two speakers per channel right? The front two channels would be a 3 ohm 6.5 coaxial and an 8 ohm 3.5 full-range driver. The back two channels will be an 8 ohm 6.5 driver and a 4 ohm tweeter. I don't know how to calculate the overall resistance between the speakers in the system or even how to wire them to be compatible with my 2 ohm stable amp. Any help would be greatly appreciated.
Series Parallel Speaker Impedance

Problem Solved.
 

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You're gonna need some passive crossovers in there if you don't already have them.
 

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That wiring page is a great reference!

Indeed, you're gunna need some passive crossovers to split up those signals, especially for the tweeter (if nothing else). The 3.5" won't survive very long either :)

If you're using a passive crossover(as in your speakers were bought as a set or you're using something from another set), the impedance wont be 2 ohms per channel, it should be closer to 4 ohms. I'm guessing that you assembled the speakers piece by piece rather than in a set?

Most amps are going to be 2 ohm stable anyways and at those frequencies (~80hz and up) it will be relatively easy to drive.
 

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Discussion Starter #5
I was already on that website and I didn't see where it says how to wire 4 pairs of speakers, each pair with a different impedance, down to 2 ohms or higher. I plan on using crossovers for the tweets and the 3.5s but I still don't know how to wire the entire system to make it work for the amp. I'll reiterate because the way I worded my post may have been confusing.
I plan on running 2 speakers per channel, the front two channels will each have one 8 ohm 3.5 and one 3 ohm 6.5 speaker, the rear two channels will each have one 4 ohm tweeter and one 8 ohm 6.5 speaker. How do you wire the system to create an overall impedance of 2 ohms or higher?
 

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in both cases, the front and rear channels will both be above 2 ohms (assuming no crossovers), but remember that impedance is not a static value, it changes as the speaker plays.
 

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Discussion Starter #7
Is the impedance determined by the way the speakers are wired on each channel? or is it determined by the way the entire system is wired? I would assume it's the entire system but I'm getting slightly confused as to how you guys are getting these numbers. Can anyone be more specific as to how to determine the impedance load for a 4-channel amp? Sorry I don't know much about 4-channel amps.
 

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Discussion Starter #8
I have a full understanding of how to determine resistance in a normal system, such as R1+R2=R3 for series and 1/R1+1/R2=1/R3 for parallel, but I don't understand how to calculate all of this for a system like the one I am describing that is using a 4-channel amp.
 

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Its one channel at a time. Thats how all amps are imp rated unless you are bridging two channels together.
In that case the two channels are summed into one for instance a two channel amp bridged for a single speaker.
So your working with four channels each channel differs from all the others.
Say channel 1-4 is rated at 2ohms or higher that means each channel can handle a load of 2 ohms or more.
In your case your above 2 on all channels. Stop thinking about that and move on to how your going to cross everything a tweet and 3 1/2 mid are not going to last very long at any kind of volume unless your using some kind of crossover.
 

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Its one channel at a time. Thats how all amps are imp rated unless you are bridging two channels together.
In that case the two channels are summed into one for instance a two channel amp bridged for a single speaker.
So your working with four channels each channel differs from all the others.
Say channel 1-4 is rated at 2ohms or higher that means each channel can handle a load of 2 ohms or more.
In your case your above 2 on all channels. Stop thinking about that and move on to how your going to cross everything a tweet and 3 1/2 mid are not going to last very long at any kind of volume unless your using some kind of crossover.
X2!

Bret
PPI-ART COLLECTOR
 

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Yes, please use passive x-overs for both the tweeters and 3.5's... otherwise stuff is gunna blow up :eek:

Do you plan on using some off the shelf crossovers or just simply wire a cap (bass-blocker) inline?
 

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Discussion Starter #15
Haven't gotten that far yet but I don't really know much about either. I know what they do and how they work I just don't know where to look for them or what to look for. Will I still be able to use the crossovers on the amp for the speakers since I will be using a crossover for the 3.5s and tweeters?
 

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Haven't gotten that far yet but I don't really know much about either. I know what they do and how they work I just don't know where to look for them or what to look for. Will I still be able to use the crossovers on the amp for the speakers since I will be using a crossover for the 3.5s and tweeters?
I suggest that you star reading and learning before you just go and jump in.
I will give you tip though 8 speakers is ALOT for a car. Just to give you an idea you will only need three at the most for a good front stage and it really has alot going on like first of all you will to bandpass two sets the 6.5 starting anywere around with a point of 60 hrz on the lowend and 200 to 300 0n the highside and again with 3.5 200 or 300 on the lowside and anywere between 2000 to about 6000 on the high side.
then you have the tweet depending upon where you crossed your mid you could be anywere between 2500 to 6000 on the lowside then it will play as high as it can or you can hear.
Thats just three speakers done properly so....... READ MAN.
 

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60Hz is too low. 80-100 depending on the speakers. And bring 6.5"s up to about 400-500Hz when crossing to 3-4" midranges. 3-4kHz on the tweeter (2-3kHz in a 2-way).
 
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