I have right now 2 JL audio 10W0's that are 4ohm and I believe they are dual voice coil(4 prongs on each speaker).
I just purchased a box to hold 3 tens and I would like to use those speakers in my setup. The JL audio 10W0 series comes in either a 4,8,or 12 ohm.

Now the 2 questions. First, which ohm speaker do I get, to let me keep a 4 ohm load with all 3 speakers running off 1 channel?

Second, After picking the correct ohm speaker, how should I wire them to attain the 4 ohm load.

Thanks



------------------

 

You can't get a single 4 ohm load from those subs. Series-wire the two coils of each speaker together. Then you have 3 speakers each with an 8 ohm total load. Parallel those and you wind up with a 2.67 ohm load. That's the closest you're going to come.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

well as far as i know u cant do it unless u get 3 subs that r 12ohms each. i did it once 3 12's all in parallel and it ran all day never shutting the amp down.

 

Three 12 Ohm speakers, all wired in parallel, give you 48 Ohms. The equation is:

(R1XR2XR3) divided by (R1+R2+R3)


R=speakers resistance

This gives you the Ohms that the amp sees.

If you run two in series, then the other in parallel, you come up with only 12 Ohms. That's the lowest value that you can recieve with three 12 Ohm speakers.

------------------
'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...

 

3 12 ohm speakers will give you 4 ohms.

Parallel eq.:

(1/r1)+(1/r2)+(1/r3)+...etc.=1/rtotal
so...
1/12+1/12+1/12=3/12
since the final resistance is 1 over the total resistance it becomes 12/3 ohms or 4 ohms

Series wiring is simple addition:

12+12+12=48 ohms

I just checked JL's site and the w0 comes in 4,8,12 ohm Single Voice Coils (SVC). Now either you have a w3 which comes in Dual Voice Coils (DVC) or you might be mistaken an the number of terminals on the back of the speaker.

It would also be helpful to know what amp you are running. Some amps can handle lower impeadance levels.


If you have Dual Voice Coils (DVC's) and the total impeadance for each speaker is four ohms then it can be either a dual 2 ohm speaker or a dual 8 ohm speaker meaning that each coil is 2 or 8 ohms. Either way you can't get 4 ohms with 3 speakers. You can get close but it might harm your amp if you go on the low side and you would get less power if you go on the high side.

One last thing it would not be a good idea to mix the impeadance ratings of speakers it will distribute the power unevenly and will sound a bit strange.

[This message has been edited by camaroguy99 (edited December 27, 2000).]

 

Hey camaro guy, re-check your math.

 

Maybe I'm wrong about the equation for parallel. I got it out of a book on electronics. The equation for wireing series is to add the resistances together. The equation for parallel, says like I said before. It could be wrong though. I thought 48 Ohms sounded off.

 

camaroguy was right with his equations and his math.

aside from being a jl dealer i also have an electronics degree. jl invented the 12 ohm voice coil so you could parallel 3 12ohm speakers together to obtain a four ohm load.

parallel resistance = 1/((1/RT1)+(1/RT2)+(1/RT3))=RT total

series resistance is RT1 + RT2 + RT3=RT total

you never want to series speakers together because you will get emf distortion. but it is alright to series parallel speakers together like the jlw6 dual 6 ohm speakers beause the speaker are electricaly isolated from each others own voice coil. with a series connected speakers share the same currant path which leads to emf distortion and one sub still moving after the music has stopped..

 

Thank you for the information on the equations. I said to check the math for the fact that three 12 Ohm speakers, wired in series, equals 36 Ohms.

 

sorry, I went quickly on that part and wasn't thinking.

 

DeVry graduate?

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

jim85iroc just because you never learned of back emf at ITT does not give you the right to say it doesnt exsist. i go through many trainning seminars though out the year and jl audio did a demo of this very subject.

if you want to learn more about back emf distortion go to there website.

here is a quote from there website.

The problem with this, is that it is less
desirable to wire subwoofers in series to each other (as opposed to parallel). Because of slight and unavoidable differences between speakers and because of the high likelihood of uneven loading between different speakers in a car, there will be slight differences in the mechanical behavior of the two speakers in series. These differences in movement result in induced voltage (called back EMF) being created by the speakers across the series connection. This effect causes a problem when two speakers which behave differently are connected in series because the speakers can modulate each other (cause each other to move), resulting in distortion. The problem becomes more serious as more speakers are connected in series. A good experiment to show the effect of back EMF is the following: connect four speakers in series and short the positive and negative input leads of the series circuit. Push down on one cone with your hand; you will notice that the three other speakers will move in the opposite direction of the one you are pushing. Now,reconnect the speakers in parallel, short the inputs and push down on one cone. The speakers will not modulate each other because each one is shorted directly.
Now, lets get back to our original scenario
if wanting to hook up four ten inch woofers
to a 4 ohm mono load. The dual 8 ohm voice coil subwoofers allow us to do this without worrying about back EMF-inducednon-linearities. Back EMF modulation is not a concern when the voice coils of a dual voice coil speaker are wired in series to each other because the coils are physically coupled on one moving mass. Therefore, they cannot possibly modulate each other because they cannot move differently.With this in mind, we can take our dual 8 ohm voice coil drivers and hook
up the voice coils of each speaker to each other in series, making each one a 16 ohm driver. Then, we simply hook up the four 16 ohm speakers in parallel to the amp, giving us our 4 ohm monoload without a speaker-to-speaker series connection and any of the negative effects described above.

 

Jim, dont get offended by that, the cool thing is that we always learn something new...remember, its always better to remain openminded than closeminded...

 

although it exists, personally I feel it is generally too minor of a concern for a user to worry about. There is virtually no case in car audio where you'll have more than 2 subs series wired and with just 2 subs, it really is a non issue. The EMF induced is a result of non-identical cone movement between two series wired drivers. Except with the cheapest of cheap drivers, they will be close enough that this effect will be minimal. The example that JL gave shows that yes, it is a genuine phenominon, but they also used a demonstration that is totally different than a real world secenario. In their example, they are causing one sub to have a 100% different movement than the others. When moving that cone, it creates a voltage in the coil, which is transmitted directly to the other subs. When dealing with high power signals from an amplifier, the minimal signals generated from a non-identical pair of series wired speakers will be negledgable, and totally masked by the signal from the amp. In addition, the higher impedance of the load will allow the amplifier to have a substantially higher damping factor, which in 99.44% of all cases will result in better cone control despite the minor amounts of emf induced by the series wired speakers.

Short story: Does it happen? Yes. Does it matter? Not enough for me to worry about.

But Chris, I do appreciate the info from JL. Although they make a mountian out of a mole-hill sometimes, they do have some very valuable information. I also like these discussions when people come armed! It gives us all a chance to learn something. Usually when somebody disagrees with others, they just get mad and resort to name calling instead of substantiating their opinion. As long as somebody can substantiate their opinion like you did, it seems to always spawn a good conversation/debate that we all wind up learning from.


------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

[This message has been edited by Jim85IROC (edited December 31, 2000).]

 

jim, well thought out reply. i am also glad that you didnt resort to name calling etc. althought it seem that you are allot more knoligable about electronics then me. i always try and obey what a manufactor recommends. thanks for the info.

current system: alpine 7909 deck,5959 changer
mb quarts 5.25 q sieres indash. mb quart 3 way in the rear sails with an eight midbass,5.25 midrande and 1 inch tweeter. for the sub three 10w6s and powering the system is one esoteric e7402 (1600w rms) and one esoteric e7104 (100w x 4 rms)

 

Both of you are "poo-poo heads"!! But your both right. While some have the "golden room" to listen to their systems, others have exhaust and other factors that will overpower most indifferences.