Guv'nor

The most common methods to wire up speakers are Series and Parallel.

It is also quite common to wire Speakers in a Series/Parallel Combination.


Single speaker

Wiring up Speakers correctly to provide the best possible sound, requires some knowledge of Loading, Phase, and Impedance, while understanding Ohms Law will help you to connect your speakers properly.

SERIES



Adding Speakers in series increases the overall resistance of the circuit.

Therefore the resistance of each Speaker is added together, For advanced installations with Multiple Speakers, Series Speaker wiring can be used to increase the resistance of the “equivalent” or “overall” resistance that the Amplifier sees. This allows the Amplifier to run cooler and more efficiently.

Series Circuits are “voltage dividers”, and using Ohms Law, one sees the result as a decrease in amplified voltage audio signal to each Speaker. Since Series Circuits are “voltage dividers” each Speaker sees a percentage of the amplified output from the Amplifier. It is often assumed the Amplifier is producing less output, but it still produces the same output, because each Speaker only gets a percentage of the overall power.

Formula: Znet = Z1 + Z2 + Z3 + .... + Zn

Example:

2 x 4 Ohm Speaker = 4 + 4 = 8 Ohm Load
2 x 8 Ohm Speaker = 8 + 8 = 16 Ohm Load

PARALLEL



Adding Speakers in parallel decreases the overall resistance of the circuit

Parallel Speaker Wiring combines all Speakers (+) positive Speaker leads together, and all (-) negative Speaker leads together.

Adding additional Speakers is as easy, however, adding Speakers in Parallel causes the overall resistance of the circuit to drop, as resistance drops, the current must increase according to Ohms Law. So, each time a Speaker with the same resistance is added to the parallel circuit, the current draw on the amp increases. The circuitry of the amp must be able to handle this increase in current at the reduced resistance.

Formula: Znet = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)

Example:

2 X 4 Ohm Speaker = 1 / (1/4 + 1/4 ) = 2 Ohm Load
2 x 8 Ohm Speaker = 1 / (1/8 + 1/8 ) = 4 Ohm Load

Note: If more than 2 Speakers are connected in Parallel, so long as they are all the same impedance then the net impedance of the load is equal to the impedance of the one Speaker divided by the total number of Speakers. For Example 3 8 Ohm Speakers in Parallel, the Impedance is 8/3 or 2.667 Ohms.

A COMBINATION OF SERIES & PARALLEL



In reality this is just two sets of Series Speakers wired in Parallel

Formula: Znet = Znet1 + Znet2 + ... + Znetn; where Zneti = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)

Example:

4 X 8 Ohm Speaker = [1 / (1/8 + 1/8 )] + [1 / (1/8 + 1/8 )] = 4 + 4 = 8 Ohm Load

WIRING A FULL STACK

The amp usually has two speaker outputs (one for each cab)

The output jacks are wired in parallel. It means Znet = 1 / (1/Z1 + 1/Z2 + ... + 1/Zn)

Therefore having 2 cabs at 8Ohm the head will see 1 / (1/8 + 1/8 ) = 4 Ohm Load

Enjoy!

superleadfixer

Also the serie/parallel combination in a 4x12 cab will have a draker sound and a little harcher, if your amp (set up) is too dark one way to help this out would do a Parallel/series connection instead, that will give a little bit cleaner and brighter sound......... :wink:

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surfdog777

Correct me if this is wrong, I'm running both cabs in a full stack 16ohm mono, the head is set at 8 ohms....this is the correct setting, eh?

Guv'nor

1 / (1/16 + 1/16 ) = 1 / (0.0625 + 0.0625) = 1/0.125 = 8 Ohm Load

You're ok.

Jimib

I am looking at buying a cab that has 2 16ohm speakers in it, am i correct in saying my amp should be set at 8 ohms?

Thanks

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Pearse

I have a 1960A cab and looks like the speakers were refitted. there are 4 15 ohm speakers its not wired the same way as celestion would have said to wire it in their series diagram, its simpler like one speaker connected to another speaker and the two end wires are conected to the terminals. What do i choose, or do. It still works fine on the 16 omh output.

KingKong

Howdi all,

I just signed up on the forums and am in need of assistance!

I just bought a nearly new tsl 100 head, and I want to make sure my cabinet is wired for 16 ohm impedance. I'm attaching a pic. The lower terminal of the upper right speaker (as you look at the pic) is positive. I believe the top speaker terminals on the speakers on the left are positive (marked with red dot). The speakers are each 16 ohm. I believe the top two are wired together in series, the bottom two are wired together in series, and the upper pair is wired to the lower pair in parallel.

If anyone could take a look at this and share an opinion I'd appreciate it!

I'm thinking it's 16 ohms total impedance, but I'd like another opinion before I use the 16 ohm output from the tsl 100.

Thanks!
Kong

Attached Images

Marshall.jpg (70.0 KB, 130 views)

Adwex

Welcome, Kong.

It's tough to see in the pic exactly how the bottom pair is wired, but the way you describe everything is correct: top pair in series + to -, bottom pair in series + to -, with the two pairs wired together in parallel + to +, and - to -. Wired this way, if all the speakers are the same impedance individually, the total impedance of the 4 will be the same as the impedance of one, so use the 16 ohm output on the TSL.

Interesting mix of speakers. I recognize the V30, but what are the others?

Can you take a better pic detailing the wiring on the bottom pair? ...and exactly which terminals are used to connect the top and bottom pairs in parallel?

Adam

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KingKong

Thanks for the response and the welcome Adam.

I bought this cabinet in about 1990, used and battered. One of the speakers was blown, and I replaced it with the V30. After a phone call to Marshall and some checking on the internet I dated the cabinet to the late 70's and was told it was a bass cabinet.

It's pretty late here and I'm headed to bed, but tomorrow I'll open it up again and post some more detailed pictures of the wiring and speakers.

Thanks again!

-Kong

KingKong

OK, I took some more pics and here they are...

The lower 2 are original G12H 30 Watts. Above are a G12C-30 and a G12 Vintage 30.

I have no idea where these speakers rank in quality, I just know the thing sounds great. I'd love to hear anyone's assessment of this setup and if there's any reason these speakers should not be mixed!

Attached Images

	ll speaker.jpg (94.4 KB, 75 views)
	lr speaker1.jpg (90.4 KB, 61 views)
	wiring4.jpg (91.6 KB, 103 views)
	wiring5.jpg (93.8 KB, 60 views)

Adwex

Well the wiring looks correct. As far as ranking, I'd say those G12H's on the bottom rank pretty high on the quality scale. I have one new G12H Heritage, and it's a killer speaker (expensive too). The V30 is a V30...good, but not quite a G12H. I know nothing about the G12C, but from the looks of the small magnet, I'd guess that it's the weak link in your chain. I don't know, maybe it adds something the others don't have.

Good heavy gauge speaker wire too.

Post a sound clip if you can.

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kharvelan

since none of the images are showing, I was digging around to find a site that had good diagrams of both series and parallel wiring in both 2x12 and 4x12 configurations.

I found this site which I think spells it out very easily exactly how to wire:

Wiring a 4 X 12 Speaker cabinet

Wiring a 2 X 12 Speaker cabinet

hope that helps!

ironmaidencanada

does anyone know how to hook up 4 cabs(8ohms each) to one amp head, all the cabs have outs and i have 4 8 and 16 ohm outputs on the head,any help would be greatly appreciated!!thanks

Pturpin1

Need Help wiring my DSL 100 to 1 4x12 and 2 4x10 cabinets. Any help would be greatly appreciated.

Thanks

Adwex

Are the cabs both the same impedance?

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Pturpin1

Yes They're both 8 ohms.

Thanks

Adwex

Then it's simple...connect the cabs to the speaker jacks labelled something like "4 or 8 ohms only", and make sure the switch is set for 4 ohms.

Since you are connecting 2 cabs, 8 ohms each, and the speaker jacks on the back of the amp are wired in parallel, the resultant impedance will be 1/2 the impedance of just one cab alone. That's why 2 cabs, at 8 ohms each will be the same as 1 cab at 4 ohms.

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Pturpin1

Thanks
So the DSL should be set on 4 ohm.
One Line should go to the 4x12 switched to 4 ohm.
I now have two 4x10 8 ohm cabs. left to hook up.
Should I use a Y Connector?

Adwex

Huh??!!

NO !!!

Wait, I'm sorry, I mis-read your original post, I didn't know you had 2 4x10 cabs.

You cannot use all 3 cabs, you can only use 2 of them.

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Pturpin1

Bummer
thanks for the info.

Pturpin1

Just Curious.

What would happen if I did use a y connector?

Is there no way of wiring the 2 4x10 cabs (8ohm) to essentially be 1 8x10 cab 4(ohm)?

Thanks

Adwex

Yes, you can...2 4x10 cabs wired in parallel will equal 4 ohms, but if you combine that with the 8 ohm 4x12 cab, the resulting impedance will be 2.66 ohms. I don't think your amp has a setting for that.

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Pturpin1

Thanks Again

arantes71

Hello there, I have a strange (at least in my opinion) case with a 412 cabinet that a friend actually gave to me together with his JMP head because he doesnt have the energy to bother with garbage that doesnt work... His loss I suppose.

Anyway, the cabinet is a 8412 with 4 8 ohm Celestion G12L speakers, and for some reason just two of them work.

I tried the 9v battry check, and they all popped, and I followed the link above to that helpful site with wiring for dummies like me, and as far as I can see the cab is set up in series/parallell combination. The wires look completely ok as far as I can see, but just the same, the upper two speakers are dead.

I should mention too that the input socket has suffered some beating and is fixed with some of that ole duck tape.

Anyone got a clue?

Adwex

First thing I would do is take off the duct tape and see what's going on with the connections. Obviously the top 2 speakers aren't connected properly.

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arantes71

Thank you for the reply!

I did take the duct tape off, and it looks the way it should - the damage is just the plastic, not the wiring. But I have a theory about how the two speakers closest to the input is not working while the others do - I believe it has to be the first minus-plus connector between the two speakers that is broke somewhere - gonna try bypassing it...

arantes71

Must have been cheating with the 9 volt battery yesterday - one speaker is actually dead... Wonder how expensive a G12L is these days, and where to find one...

Adwex

G12L = V30

Buy Celestion Vintage 30 Speaker online at Musician's Friend

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rmrunner

can some one help me....i am running two cabinets. each cabinet has a 8 ohm horn(has condenser) and a 500W 4ohm 10''. should i run this in series arrangement or parallel arrangement? amp impedance is 6-16 ohms

cadaver_occulta

Out of curiosity, if 1 8x10 (or 8x12 i hope) cabinet equals to 4 ohms, then would there be any problem running 2 8x10 (12) cabs from 1 head if the amp has two speaker outputs?

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