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How can I wire 4 speakers to amp?

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How can I wire 4 speakers to amp?

  • Ok this is my problem....

    I want to connect 4 speakers to an amp, (2) 6.5" speakers to front doors, (2) 6x9 speakers to rear).  I don't understand much about ohms and how to wire everything to be safe and get max power handling. I don't know what amp i should get, i was thinking Sony's Xplod XM-280GTX 2-channel amplifie 480 watts, or sony's Xplod XM-2150GSX 760 watts(I'm not sure it this one is too much amp for my speakers).

    Info on Speakers:

    6.5": 150 watts RMS,  300 watts Peak Power (each)  Impedance: 4 ohms

    6x9: 175 watts RMS,  350 watts Peak Power (each)  Impedance: 4 ohms

    I found this example to guide myself buy i don't understand how to wire it to the amp to be 4-ohms giving an output power of 150 watts x2 (amp #2 below)

    Assuming they are speakers not sub woofers....

    This is the info i found on the amps i'm thinking of using.

    (1)   XM-280 GTX 480W max power,                        
    80 watts RMS x 2 at 4 ohms                                          
    120 watts x 2 at 2 ohms                                                  
    240 watts x 1 RMS bridged output at 4 ohms             
    4-ohm stable in bridged mode

    (2)   XM-2150GSX 760W max power,
    150 watts RMS x 2 at 4 ohms               
    190 watts x 2 at 2 ohms                       
    I don't know at  1 ohm            
    i don't know if 2 or 4-ohm stable in bridged mod

    I believe amp #2 works best for me but i don't know if i would blow the amp of the speakers if wiring it as the diagram giving the speakers 190 watts rms when is says 150 rms???

    Please somebody explain with details and how to wire everything.  Or if i should just do it and shown is the diagram above?

    THANK YOU VERY MUCH

     



    [edited by: J P at 7:34 PM (GMT -5) on Mon, Dec 20 2010] Chagned to discussion.
  • "Power Handling" is pretty much a meaningless spec. What you need to be concerned with is efficiency.

    Wire the speakers in parallel as shown in the diagram and the amp will see a 2 ohm nominal load. You won't be bridging anything. Keep in mind that in this scenario you are dividing the output of each channel between two speakers. There is no free ride in electronics. When you lower the nominal impedance load you increase the power output of the amp but you also increase the amount of heat produced (lowering efficiency) and you increase distortion, which is more of a concern with full-range drivers than with subs.

    If it were me I probably go with a four channel amp with one speaker on each channel so I could tweak the levels between the front and rear speakers. Choose the amp based on the efficiency of your speakers. The lower the efficiency, the more powerful amp you will need to get the same output.

     

         RESIma

  • Do you have something against 4ch amps, or were you just trying to get more watts/dollar? If you do use a 2ch amp with 4 speakers, you will either lose balance (L-R) or fade (F-R) controls. You can adjust the gains separately, but will not be able to make those adjustments from the HU.

    A four channel amp that output ~100-200W RMS per channel would be ideal for your setup. (Well honestly, anything ~50W+ would work well, but something ~150W would probably give you more bass and headroom.)

    Looking at your suggestions, you would get 60W per speaker with the XM-280, and 95W per speaker with the XM-2150. Looking only at power ratings, the second amp would probably be a better match. There is no substitute for power.

    40W over the nominal power rating will do no damage as long as you adjust your amp/HU settings accordingly. I've seen 50W speakers on amps that were rated for 300W RMS per channel with no problems. (Granted, the installer knew exactly what was going on, had the gains all the way down, and the other settings adjusted accordingly.) Basically, just adjust your gains properly, don't crank up your bass boost, and you should be fine.

    02 BMW 330Ci

    Alpine DVA-9965, and a mix of stuff

    12 Ford F-150

    In progress: Pioneer DEH-80PRS HU -> DLS RA40 amp -> Seas G18RNX woofers & SB Acoustics SB29 tweeters

  • I was looking at some 4-channel amps and it says 70 watts x4 @ 4 omhs, and 80 watts x4 @ 2 ohms.  Now, how would i wire all the speakers to make them get 80 watts at 2 ohms, how do i wire everything to be at 2 ohms??

  • You don't. That's the point.

    Wire them each to a channel at 4 ohms and they will sound great. The amp will run cooler and have less distortion. Lowering impedance just for the sake of saying you have 10 more watts is counterproductive.

    10 additional watts isn't worth the effort in any case. You need to increase output by a factor of two to get a 3dB increase in output. Get a good four-channel amp (or 2 two-channel amps), connect one 4 ohm speaker to each channel, and set the gains. Just because an amp can run at 2 ohms doesn't mean that 2 ohms is optimal in every application. In this case it is not.

    There is a reason why virtually all full range speakers and separates are 4 ohm.



    [edited by: Alex W at 7:37 PM (GMT -5) on Sun, Dec 5 2010] Corrected for a stupid error...bad Alex...bad, baaaad Alex.

         RESIma

  • Ninja1283

    If you do use a 2ch amp with 4 speakers, you will either lose balance (L-R) or fade (F-R) controls. You can adjust the gains separately, but will not be able to make those adjustments from the HU.

    Theoretically true, but you would never put both rears on the left channel and both fronts on the right, so you pretty much lose all independent gain control between the front and rear speakers.

         RESIma

  • Alex W
    You need to increase output by an order of magnitude to get a 3dB increase in output.

    For those that don't know, power must double to increase SPL by 3 dB's (with a single driver).  Going from 70 watts to 80 won't even get you a full decibel.  A decibel is the smallest change in volume that is perceptible by human ears, but in car audio where noise is ever-present, 3 dB's is considered a 'noticeable' difference.

  • J Ro

    Alex W
    You need to increase output by an order of magnitude to get a 3dB increase in output.

    For those that don't know, power must double to increase SPL by 3 dB's (with a single driver).  Going from 70 watts to 80 won't even get you a full decibel.  A decibel is the smallest change in volume that is perceptible by human ears, but in car audio where noise is ever-present, 3 dB's is considered a 'noticeable' difference.

    Right. I mis-typed. I meant to say increase the power by a factor of two to get a 3dB increase. Tee many martooni's, I guess.

    I retract. I will correct. I throw myself upon the mercy of the forum.

         RESIma

  • I should use a 4-channel amp then, this will work best for me, right?  Do you have any suggestions (make and model) on good fairly price 4-channel amps for my 2 6.5"'s and 2  6x9's? Also, one more question, my wife wishes me to change her SUV's speakers and im going to change her car sound system too, but in this case we are talking about 6 speakers total [(4) 6.5" front and rear doors, and (2) 6x9]  What amp should i use in this case? 4-channel amp? and use 2 channels with 2 speakers wired to each channel and the other 2 channels with single speaker? It will be same type of speakers (150W rms, 300 max= 6.5" .... 175 w rms, 350 Max 6x9's).

    Also, I'm putting a single 12" sub in each car, i alread have the 12's and amps for them, but i'm just stock with making a decision for a good amp to push the speakers (not the subs).

    Thnks

  • gsrteg94
    I should use a 4-channel amp then, this will work best for me, right?

    That would be my suggestion. You can get away with using a 2ch, but you will lose either balance or fade control from the HU.

    gsrteg94
    Do you have any suggestions (make and model) on good fairly price 4-channel amps for my 2 6.5"'s and 2  6x9's?

    Ninja1283
    four channel amp that output ~100-200W RMS per channel would be ideal for your setup. (Well honestly, anything ~50W+ would work well, but something ~150W would probably give you more bass and headroom.)

    Those are more budget amps, but should do the trick. Something like an Alpine MRP-F300 or Hifonics ZXi80.4 would cheaper options, but wont give you quite as much power. A Hifonics ZXi150.4 or a Sundown SAX-100.4 would be solid options with more power.

    02 BMW 330Ci

    Alpine DVA-9965, and a mix of stuff

    12 Ford F-150

    In progress: Pioneer DEH-80PRS HU -> DLS RA40 amp -> Seas G18RNX woofers & SB Acoustics SB29 tweeters

  • First off - what speakers do you have?

    I don't know very many reputable 6.5's that are 150W RMS - there are a few out there, but I know of a lot of less expensive ones (Boss, Soundstorm, Pyle) that claim that, but are really less than that.

    In any case, a good 60-100W RMS x4 amp should be fine.

    For the wife's SUV, assuming the 6x9's are in the rear, you ideally want an amp that is almost 2X the power at 2-ohms as at 4-ohms and wire the 6x9's in parallel with the rear 6.5's on the rear channels of the amp.

    Hope This Helps!!!

    Anyone else have suggestions?

     

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs

  • thank you everybody, i'll post again if i encounter some issues.