2 coax in series

I am a newbie and am having great fun learning from the info on this forum.  I am mid install on a new system (my first) and think I am trying to do something that is too complicated or just not worth doing.  I have a two channel amp that I have had for years and would like to use to power four coaxial speakers in each of four doors. I will be installing another amp and one sub in the car at a later date.  I have read about crossovers and had planned to detach the tweeters from the mids and put in nice second-order crossovers in each (they currently have just caps in line like a typical coax).  The goal is to band-pass the four mids above 80hz and below roughly 5000hz and then the tweeters above around 5000hz.  Heres the rub.  The coaxials are rated at 4 ohms each so theoretically I need to wire them in series to stay within my amps operating range (note, it is 95w rms x 2).  But, if I separate the tweeters, which come factory wired in parallel with the mids, and cross the tweeters and mids below and above the same point, I am guessing I end up with a 2 ohm pair instead of the original 4 ohms they were rated at.  IF that is the case, then I have four 2 ohm speakers on each channel of the amp.  I would wire them back in parrallel and then each pair in series to get 8 ohm loads on each channel.   I get lost at this point.  I cannot imagine which crossovers to purchase since they would be seeing different loads.  Hope this isn't too confusing, but if anyone can suggest the right way to wire this system (or recommend just abandoning the idea and either getting a 4-channel amp or running the rear doors off the head unit at 18w rms) I would appreciate your comments.   Thanks.

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GR

If you have a componenet set. typically each set would yeild a 4 ohm load...if you have a DMM measure the tweeter and then measure the woofer.   even though you would lose fader control from side to side and front to rear.    if each one of your speakers is 4 ohm.   you could wire each pair to 8 ohm, then wire 2 pairs to 4 ohm per side of the amp....I dont know what your looking for but I know you can get a few mid range 4 channel amps for less then $200   message me if you want more info about some of these amps

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 Does the amp have a high pass filter switch?  If so, you could run the coaxials through the high pass on the amp set at about 80 Hz.  That will give you the low cut-off.  Then they'll operate at 80 Hz and above.  The amp should work at 2 ohm stereo...check and see if it is spec'd to run below 4 ohm.  If it will, you can parallel the rights and lefts for a 2 ohm stereo load.  No fade control to attenuate the rears, though.  Your power would be meager at an 8 ohm load on that amp, running four speakers.

Best thing, leave the coaxials intact.  Use your amp for the fronts, head unit for the rears.  With an eye toward the future, as suggested above, search for a four channel amp to power the speakers.  If the amp you have now is bridgeable, it would be suitable to power a sub.  You want to maintain a 4 ohm load on the speakers in the car for sound quality.  8 ohms would be good, but with a more powerful and more versatile amp...and higher quality component speakers....else you won't be able to appreciate the difference in sound quality.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

To answer your question, a crossover is designed so that (to put it simply) only one speaker is "connected" to the amp at a time.  So the amp will only ever see the impedence load from one speaker.

Now, why do you want to put multiple speakers in each door?  What do you hope to gain?

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Thanks for the replys.  To answer a few questions, the amp is what people are calling "old school" now.  Not bridgeable and doesn't have any support to suggest that less than 4 ohms is ok.  As for the speakers, I have two really nice sets of coaxials from some old installs, the amp is an old kenwood from an old install also.  The speakers are memphis and jl audios with some pretty decent specs.  I am sort of building up to a nice system so wanted to use what I have for now.  I can split the memphis coaxials since the tweeters are wired with separate wires from a parallel junction at the rear of the speakers unlike some that wire through the midrange cone.  I think for simplicity, I will wire the fronts to the old amp and the rears to the deck.  That still leaves the question of what are the resistance of each component and how to cross them over so as to end up with one 4 ohm load.  Has anyone tried this? 

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GR

Like I said before, a properly designed crossover will keep the load from one speaker (or one set) connected to the amplifier and take care of your impedence loading issue.  Splitting a coaxial and turning it into a component is no big deal as long as you design the crossover properly... or simply use the crossover installed in the coax (or that comes with it.)  Now if the only reason you want to do this is because you have the speakers laying around and you want to experiment, go for it.  If you are trying to achieve a specific purpose maybe we can help you in your system design, but you'll have to explain what you're trying to create a bit more clearly.

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Thanks for the replies.  Based on what I have read, if a typical coax is powered from 80 hz and above and only has the capacitor in line on the tweeter portion, there is likely a duplication of sound and an unnatural decibel increase over the ranged that they overlap.  I guess this is the reason for components.  That said, my purpose in looking into splitting the coaxials and adding some nice crossovers is to creat a more linear response from the tweeter/midwoofer pair.  I got some feedback from Memphis.   They said that the tweeter is somewhat weak on their paired coax and relies heavily on the midwoofer.   Both have 3.6 ohms impedence but the tweeter doesn't pick up until about 7khz.  From what I have seen, most band pass crossovers cross at around 5k on the high end.  

I am still not convinced to go ahead and separate them, but it is tempting.  If I did, I am guessing that a nice band pass from 80 to 7k  and then a high pass above 7k would work well with these speakers.  Any thoughts from those of you who have more experience than me with this sort of thing?

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GR