Series - Parallel wiring for multiple tops

[fvodo]

Hello All.

First post. What a site! (I have been reading for over 18 months)

I have 6 OT12's (Thanks for 4 of them Wi). I have a Crown XTI4000 and would like to drive all 6 (mono) from a single channel of the XTI4000 (when the gig demands it).

Can I parallel the right side set of 3 and then parallel the left side set of three and then combine them in a series wiring configuration for a ~5 Ohm load at the amp?
RHS ~2.7 ohms \
| series wired to give ~5.4 ohms to 1 amp channel
LHS ~2.7 ohms /

I have seen bgavin's comments on 3 sets of 2 series but I don't believe that works for me.

Any other considerations or suggestions?

Thanks.

[Israel]

it can be done this will be 5.33 ohms and u can drive the subs with the other channel this will be a hard task for a single amp but providing that you do not crank the amp over the limits it can be done... recommendations have a spare amp on hand

[Ron K]

5.3 ohm load on one channel wont hurt at all.You're just going to be splitting power between cabs however. You'll be giving each box around 175 watts at full tilt.

Best way to do that is make up a breakout box where you simply plug the amp into one end and have 2 outputs of which the series circuit is already configured.This will also allow you to run split cables to either side of the venue keeping the leads the same length if you are splitting the tops left and right side. Then you can run parallel small cables between boxes on either side leaving the box input jacks standard configuration.

[SeisTres]

it can be done this will be 5.33 ohms and u can drive the subs with the other channel this will be a hard task for a single amp but providing that you do not crank the amp over the limits it can be done... recommendations have a spare amp on hand

As long as the subs on the other channel stay above the minimum recommended impedance, the amp could care less if it had 10 subs or two hooked up to it. However, power handling will double when you series the cabs, but that does not mean the amp will put out more volts.

For reference, i run 3 titans (3.3 ohm) and two jacks (4ohm) of the same amp and this has never given me any problems. Even on my behringer powered mixer(which ironically, i use the most)

[Ron K]

power handling will double when you series the cabs

A series circuit will not double the power handling.

Scenario)

amp output is capable of:

50 watts @ 16 ohms
100 watts @ 8 ohms
200 watts @ 4 ohms

Drivers:100 watts @ 8 ohms

2-8 ohm drivers wired in series will create a 16 ohm load. The amp will output 50 watts, but each driver can handle 100 watts over the coil. 50 watts is all that will drop across the coils resulting in a reduced overall output.

2-8 ohm Drivers wired in parallel will yield a 4 ohm load to the amp.This load allows the amp to output 200 watts and the circuit to handle 200 watts @ 4ohms. Each speaker can now see the full 100 watts each.

Of course in the real world of amp output, as impedance lowers or raises power output never really halves or doubles. The only way I can think of doing that precisely is with very carefully designed Class A amps. These dont lend themselves well to live use.

The voice coils can only handle what they are rated for! By arranging the coils in different schemes you can influence the amps output ability but you cannot change how much power can be dissipated by each coil.

Raising the load impedance results in a loss of output and lowering the load impedance results in an increase in output. How low you can go is largely determined by the amps topology!

[SeisTres]

power handling will double when you series the cabs

A series circuit will not double the power handling.

What I meant is not that the power handling of each individual driver will double but the overall power handling of the system will.

Not that I reread the whole thing, I made a mistake and what I was trying ot point out is that the allowable voltage will double

It just hit me that when you parallel or series two cabs, the power handling will double either way.

Thanks for catching that one.

[Mikey]

My (limited) understanding is that:

* Parallel-wired drivers retain the same voltage to each driver, but series-wired drivers (or groups of drivers) cause voltage to be split ... 2 series drivers get 1/2 of the amp's output voltage each / 3 series drivers get 1/3 of the amp's output voltage each / etc.

* Regardless whether wired in series or parallel, a group of drivers' power handling is the sum of the power handling of the individual drivers.

* A group of parallel-wired drivers increases in sensitivity as drivers are added, but sensitivity is not increased when drivers are wired in series.

Feel free to correct me if I'm wrong. It won't hurt my feelings, as I'd rather know if my understanding has been incorrect.

[Ron K]

Parallel-wired drivers retain the same voltage to each driver, but series-wired drivers (or groups of drivers) cause voltage to be split ... 2 series drivers get 1/2 of the amp's output voltage each / 3 series drivers get 1/3 of the amp's output voltage each / etc.

+1 The voltage drop across each resistive component must always be equal to the circuits total voltage.If the amp outputs 10 volts against a 16ohm load and 2- 8 ohm drivers are series wired in that circuit then each driver will see a 5 volt drop across them. The sum of these two 5 volt drops will always equal the 10 volt output at the amp.

The laws of conservation of energy cannot be changed.

Here's an easy reference to figuring out Power and Voltage etc. in series or parallel circuits.

http://www.termpro.com/articles/spkrz.html

[Mikey]

That's a good link, Ron. It thoroughly covers the math for series, parallel, and series/parallel combo wiring. There are simpler ways to do it, but for teaching purposes, the thorough explanation is a good thing. Unfortunately, it doesn't cover the issue of sensitivity in relation to these circuits, which is an especially important factor in pro sound, where drivers are relatively expensive and amps large enough to provide "sufficient" voltage to series-wired, relatively high-power-handling drivers could be very pricey. In most cases, series-wiring your drivers results in poor bang-for-the-buck. Unfortunately, I'm out of time this morning. When I have time, I'll try to search for a good article that thoroughly explains it and post the link here.

[Ron K]

I haven't looked but Syd may have already have something referenced to in the Educational Links.