# Series or Parallel for Doubling Up a Channel?



## ZeosPantera (Sep 12, 2009)

I have been a bit confused by some electrical engineers recently when I brought up using a pair of speakers for a center channel. It basically boiled down to _two 8 ohm speakers can never be wired to draw 8 ohm_ and that confused me. How can adding more drivers change the ohm load if a speaker with twice the drivers can also be 8 ohm(think center channel speakers vs bookshelf). Does it have to do with the crossover? All the pages I found explaining series and parallel connection of speakers are based pretty much in car audio so I am not sure if it applies prefixing a crossover.










http://www.crutchfield.com/S-CALlWQl6hTf/learn/learningcenter/car/amplifiers_faq.html#13

So the question comes back. Series or Parallel? And why can't I wire 2 speakers to 8 ohm.:scratch:


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## eugovector (Sep 4, 2006)

You can wire two 4 ohm speakers in series to get 8 ohms or two 16 ohm speakers in parallel to get 8 ohms.


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## jackfish (Dec 27, 2006)

An 8 Ohm center channel speaker likely has two 4 Ohm midbass drivers wired in series.

http://www.bcae1.com/spkrmlti.htm

http://www.audioholics.com/educatio...ance-series-parallel-connection-basics-page-2

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


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## bambino (Feb 21, 2010)

Home audio drivers generally are 8 ohms while car audio is usually 4 ohms. Why, i don't know, so your home speakers are probly 8 ohms, if you series them you'l end up with a 16 ohm load on your AVR or Amp which would make them easier for the amp to drive. If you parallel them you'll create a 4 ohm load which would be just the opposite and would put more demand on your amp.


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## ZeosPantera (Sep 12, 2009)

bambino said:


> Home audio drivers generally are 8 ohms while car audio is usually 4 ohms. Why, i don't know, so your home speakers are probly 8 ohms, if you series them you'l end up with a 16 ohm load on your AVR or Amp which would make them easier for the amp to drive. If you parallel them you'll create a 4 ohm load which would be just the opposite and would put more demand on your amp.


I think 4 ohm drivers are made more resilient (surrounds and such) for the harsh conditions a car must withstand. What you said makes sense but the issue still bothers me. Could lowering the load to 16 ohm change the audio characteristics? Same with pushing the amp to 4 ohm. And wouldn't it mean I could wire 4 speakers to a channel raise the ohm load to 64 and it would be easier on the amp? I doubt it. On the other hand wiring 4 speakers, a pair in series and a pair in parallel should get the load back to 8 ohms..


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## bambino (Feb 21, 2010)

Bringing the load backdown to 8 ohms using four seperate speakers would be possible, but the question then is can the amplifier deliver enough power to sufficiently drive the four speakers? :dontknow:


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## ZeosPantera (Sep 12, 2009)

bambino said:


> Bringing the load backdown to 8 ohms using four seperate speakers would be possible, but the question then is can the amplifier deliver enough power to sufficiently drive the four speakers? :dontknow:


When I test I only have 2 pr to deal with. Of these. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-652 40 watts RMS/75 watts max. Superb Speakers as I can vouch and you can read in the review here.. http://news.cnet.com/8301-13645_3-20016275-47.html
The endgame is to get a pair running off my Denon 589's center but if power is what is needed I can test by hooking them up to the Pioneer Spec-2.

Certainly any amp I test with could power them at either 16ohm or 4ohm long enough to tell if there is a difference.


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## bambino (Feb 21, 2010)

All you can do is try. I wouldn't want you to hurt your AVR as many brands are not comfortable running 4 ohm loads for long allthough protection should be built into the unit for such instances, on the other hand i wouldn't worry about a 16 ohm load.

I do not like to guess at this kind of stuff but i'd say with a 4ohm load your AVR will kick in to protection fairly quickly. 
Have you gone through the Manual thoroughly?


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## ZeosPantera (Sep 12, 2009)

bambino said:


> Have you gone through the Manual thoroughly?


Just found my downloaded copy. Says to use speakers of 6-16 ohm and when using A+B Simultaneously (Which I do Alot) the speakers should be 12-16 ohm. So I have been using four 8 ohms simultaneously for months with no issue. 

It also says the unit may overheat with a 4 ohm load and trip the protection. Not likely with my active cooling solution on it.


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## bambino (Feb 21, 2010)

Be sure to post your findings as i'm curious as to what you come up with.:T


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## salvasol (Oct 31, 2006)

ZeosPantera said:


> Says to use speakers of 6-16 ohm and when using A+B Simultaneously (Which I do Alot) the speakers should be 12-16 ohm. So I have been using four 8 ohms simultaneously for months with no issue.


Good to know I'm not alone :bigsmile:

I been using seven pairs for years and no problem. I also use A+B, but I'm using a speaker selector with matching impedance to avoid any damage to the AVR, by the way is a Sony STR DG600 (100WPC).



> It also says the unit may overheat with a 4 ohm load and trip the protection. Not likely with my active cooling solution on it.


I did the same (JBL stadium in parallel, AVR was Sony STR DE997 100WPC not rated for 4ohm loads), then I got a Yamaha RXV 2700 rated for 4ohms... never had a problem.

Currently I'm powering the JBL's with a pro-amp (Samsom Servo 600) :T


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## lcaillo (May 2, 2006)

If you don't push hard, and the output devices stay relatively cool, you will likely be ok with many decent amps or receivers even with a lower impedance than they are designed for. You will likely shorten the life of the outputs and perhaps the power supply if you push it harder, however.


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## ZeosPantera (Sep 12, 2009)

lcaillo said:


> If you don't push hard, and the output devices stay relatively cool, you will likely be ok with many decent amps or receivers even with a lower impedance than they are designed for. You will likely shorten the life of the outputs and perhaps the power supply if you push it harder, however.


So would wiring in series and upping the ohms to 16 mean I am saving the life of my outputs and PS? I just find it hard to believe that would be the case. I am going to have to break down and risk testing on one of my amps. The Spec2 has a 4 ohm 8 ohm selector in back so that sort of concerns me. It's an old dog too so using that to "test" with doesn't exactly thrill me although its the cleanest and most powerful amp I have access to. 

Its all about screwing up sound quality at this point. If 16 ohm works perfectly with no discernible degradation then series it is. If it only sounds clean when in parallel and pushing a 4 ohm load then so be it.

I will report back when I have concluded whats best or if something melts.


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## lcaillo (May 2, 2006)

The speaker impedance selector probably just limits the voltage swing on the power supply to keep you from driving the unit too hard. It will have the same effect on volume as putting the speakers in series, but without the possible unpredictable effects on frequency response that you get with series connections.

The bottom line is that your amp's power supply and output devices can only deliver so much current. Lower impedance loads draw more current. More current means more heat. Heat, beyond a point is bad for the life of electronics. There is no way to get around the limits of an amp other than to not try to drive it harder than the levels where it can reliably operate. Adding more load means you will not be able to drive the amp as hard without potential damage, period.


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## Wayne A. Pflughaupt (Apr 13, 2006)

> So would wiring in series and upping the ohms to 16 mean I am saving the life of my outputs and PS? I just find it hard to believe that would be the case.


Why is that?

Regards,
Wayne


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## jackfish (Dec 27, 2006)

ZeosPantera said:


> So would wiring in series and upping the ohms to 16 mean I am saving the life of my outputs and PS? I just find it hard to believe that would be the case.


 It would also limit the output of the amplifier and ultimately loudspeaker SPL.


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## Mike P. (Apr 6, 2007)

> So would wiring in series and upping the ohms to 16 mean I am saving the life of my outputs and PS? I just find it hard to believe that would be the case.


Less heat generated = longer life.


http://www.hometheatershack.com/forums/33606-series-parallel-doubling-up-channel.html#ixzz111VcpQ4k ​


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## Kal Rubinson (Aug 3, 2006)

So, it boils down to goals and compromises.

Ideally, one should not "double-up" the speakers on any channel for acoustical reasons as a pair of nearby speakers will interact acoustically (and unpredictably) depending on the spacing and program content. Just use a single speaker with adequate sensitivity and power handling for that application.

Using a pair in parallel will halve the impedance (double the load) seen by the amp and it will depend on the amp's capabilities whether that load is stressful or within the design spec. If the latter and there is a pressing need for the two speakers, this is an acceptable configuration (given the objections above).

Using a pair in series will double the impedance (halve the load) seen by the amp and, in most cases, will not present any problems for the amp. OTOH, each speaker system will have the other (with all its reactive elements) in series with it and the result is likely a disruption of FR and other parameters. This might work OK for identical single drivers (as installed in some MTMs) but the complexity of multidriver systems with crossovers is another matter. You can try it but my experience is that this arrangement is too big a sonic compromise to be acceptable.

Kal


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## ZeosPantera (Sep 12, 2009)

Wayne A. Pflughaupt said:


> Why is that?


Just seems doubling the amount of drivers shouldn't make life easier on an amp. Dam you electrical principals!



Kal Rubinson said:


> Ideally, one should not "double-up" the speakers on any channel for acoustical reasons as a pair of nearby speakers will interact acoustically (and unpredictably) depending on the spacing and program content. Just use a single speaker with adequate sensitivity and power handling for that application.


I am one of those people who can tell that people speaking from the center channel are 3 feet below the center of my projection screen and I can't stand it. I currently have a 2.1 KLH AT2100i system split top and bottom for my center with very pleasing results. Just looking to improve the tonal quality with those Dayton's.


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## bambino (Feb 21, 2010)

Just out of curiousity have you tried aiming or positioning the center channel for better imaging? That would make a huge improvement.:T


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## Kal Rubinson (Aug 3, 2006)

ZeosPantera said:


> I am one of those people who can tell that people speaking from the center channel are 3 feet below the center of my projection screen and I can't stand it. I currently have a 2.1 KLH AT2100i system split top and bottom for my center with very pleasing results. Just looking to improve the tonal quality with those Dayton's.


That's why they invented AT screens. OTOH, I am one of those guys who will sacrifice video for the sake of audio, so my responses are biased. Consequently, imho, almost anything will be an improvement on the KLH. :whistling:


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## ZeosPantera (Sep 12, 2009)

bambino said:


> Just out of curiousity have you tried aiming or positioning the center channel for better imaging? That would make a huge improvement.:T


Have tried. I am just too close (~10' from a 92" screen) for aiming to work. I am sure I would have been better off with a single on top but the effort to hang a really large center seemed silly.



Kal Rubinson said:


> That's why they invented AT screens. ROFL, I am one of those guys who will sacrifice video for the sake of audio, so my responses are biased. Consequently, , almost anything will be an improvement on the KLH. :whistling:


If I could afford an audio transparent screen I would have one. Are the cheapest still ~4K? And in their defense I really was impressed by these KLH's when I got them a few years back. Plus the benefit of having a fully self contained and powered 2.1 system with it's own 8" sealed sub and an adjustable crossover acting as a center makes huge difference compared to just a decent center. There is so much info on that channel you could almost call the front left and rights just effects channels in most movies. 5.3 FTW!


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## Wayne A. Pflughaupt (Apr 13, 2006)

ZeosPantera said:


> Wayne A. Pflughaupt said:
> 
> 
> > > So would wiring in series and upping the ohms to 16 mean I am saving the life of my outputs and PS? I just find it hard to believe that would be the case.
> ...


It’s not so much the number of drivers as it is the load (impedance/resistance). Keep in mind that zero-ohms is a _dead short_. If you dead-short speaker wires, you’ve created a _maximum load_. There is no resistance in the line, so the amp can only generate an unabated amperage (power/watts) surge. IOW, the amp designed for say 200 watts is trying to generate 2,000. It overheats and shuts down. 

Naturally, the further an amp “gets” from zero ohms - 4, 8, 16, etc. ohms - the less it has to “work.” The added resistance means less current draw (watts demanded). The amp runs cooler and lasts longer because it’s an easy load. 

Kind of a crude example, but does that make sense?

Regards,
Wayne


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## ZeosPantera (Sep 12, 2009)

Wayne A. Pflughaupt said:


> Kind of a crude example, but does that make sense?



Actually yes.. That made perfect sense. Thank you


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## eugovector (Sep 4, 2006)

You can DIY an AT from Seymour AV for about $300 if memory serves. I think about $1000 will get you preassembled.
_Posted via Mobile Device_


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## ZeosPantera (Sep 12, 2009)

eugovector said:


> You can DIY an AT from Seymour AV for about $300 if memory serves. I think about $1000 will get you preassembled.
> _Posted via Mobile Device_



Very interesting. I would completely consider that if I were re-doing my setup. Currently I have to have a pulldown so the cost is prohibitive.

Now onto an interesting question. I have a 10" Passive Dual Voice Coil sub (8ohm) that has a set of 8 ohm speakers after it. What load does the amp see when I wire through the sub?.. What load would it see if I wired the speakers and sub directly to bypass the sub's crossover?


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## eugovector (Sep 4, 2006)

A passive radiator has no load, it's not a speaker so you likely have one 8 ohm driver and one no load passive radiator. Also, the sub likely has it's own amp, so your AVR isn't powering it. A crossover has no affect on speaker impedance. An 8 ohm speaker, whether crossed over at 50 hz or 500 hz is still 8 ohm. Now, if you're talking about the total load of individual component in a speaker (tweeter, midrange, woofer, crossover), that's another matter.


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## eugovector (Sep 4, 2006)

Now, as I'm re-reading this, I see that you meant dual-coil speakers, not passive radiators. A dual coil speaker at 8ohms has 2 coils at 8 ohms each. You can wire a single speaker as 4 or 16 ohms, or a pair as 2 or 8. You either add the restance or divide by two depending on whether you're going parallel or series.


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## vicdog (May 5, 2009)

Can you wire speakers in series? I don't think that would work.


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## salvasol (Oct 31, 2006)

ZeosPantera said:


> ... I have a 10" Passive Dual Voice Coil sub (8ohm) that has a set of 8 ohm speakers after it. What load does the amp see when I wire through the sub?..


Probably will see 16ohm (8+8) :huh:



> ...What load would it see if I wired the speakers and sub directly to bypass the sub's crossover?


What do you mean directly??? ... sub to sub output, and speaker to speaker terminal???

If that's the case, it will see the sub or speaker impedance (8ohm)


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## salvasol (Oct 31, 2006)

vicdog said:


> Can you wire speakers in series? I don't think that would work.


Can you explain Why not???

I have a pair of speakers wired in parallel, and they work fine .... :blink:


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## ZeosPantera (Sep 12, 2009)

vicdog said:


> Can you wire speakers in series? I don't think that would work.


You can and it is apparently better for your amplifier!



eugovector said:


> Now, as I'm re-reading this, I see that you meant dual-coil speakers, not passive radiators. A dual coil speaker at 8ohms has 2 coils at 8 ohms each. You can wire a single speaker as 4 or 16 ohms, or a pair as 2 or 8. You either add the Resistance or divide by two depending on whether you're going parallel or series.


Basic math must now be applied



salvasol said:


> Probably will see 16ohm (8+8) :huh:
> 
> What do you mean directly??? ... sub to sub output, and speaker to speaker terminal???
> 
> If that's the case, it will see the sub or speaker impedance (8ohm)


By Directly i mean in parallel. Which should make it 4 ohm. But That's why I asked about wiring through it. One would imagine making an 8 ohm passive would somehow try to keep the load with speakers to 8 ohm.


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## Lucky7! (Jan 7, 2008)

vicdog said:


> Can you wire speakers in series? I don't think that would work.


Yes, you can, but it's best done with single driers than multi way speakers with passive xovers as Kal explains in post 18.


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## salvasol (Oct 31, 2006)

ZeosPantera said:


> By Directly i mean in parallel. Which should make it 4 ohm. But That's why I asked about wiring through it. One would imagine making an 8 ohm passive would somehow try to keep the load with speakers to 8 ohm.


Does the manual of your sub mention anything about impedance when connecting sub and speaker to AVR???

For example, I think most AVR's that have a speaker selector (A + B) are designed to see a series connection when using A+B at the same time.

Maybe is the same with the sub, when you connect a speaker to the sub, the AVR will see either a series or parallel connection, depending on the design :huh:


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## Lucky7! (Jan 7, 2008)

salvasol said:


> For example, I think most AVR's that have a speaker selector (A + B) are designed to see a series connection when using A+B at the same time.


I doubt this. Every schematic I have ever seen has A+B in parallel.


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## salvasol (Oct 31, 2006)

A9X said:


> I doubt this. Every schematic I have ever seen has A+B in parallel.


My mistake... I wasn't sure if it was series or parallel :T


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## ZeosPantera (Sep 12, 2009)

salvasol said:


> Does the manual of your sub mention anything about impedance when connecting sub and speaker to AVR???


No, this sub was a gift from a neighbor that moved away. Its a Design Acoustic PS-SW 10" and I cant find hide nor hair about it on the interwebs.



salvasol said:


> For example, I think most AVR's that have a speaker selector (A + B) are designed to see a series connection when using A+B at the same time.


That would be only relevant for an AVR with A+B. The sub on my Pioneer Spec 2 http://www.hificlassic.dk/billeder/gallerier/spec2.jpg But I have it currently wired parallel because I think the subs crossover was choking the B652's range too much.


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## salvasol (Oct 31, 2006)

ZeosPantera said:


> That would be only relevant for an AVR with A+B...


Yes I understand, what I mean is that probably the XO/electronic board (if there's one) inside the sub are designed to represent a series or parallel connection to the AVR when using a speaker...

e.g.: Sub alone 6ohms (that's what i found out online, but you mention 8ohms)
Sub + speaker: series 6+8= 14 parallel 6+8/2= 7 :huh:


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## ZeosPantera (Sep 12, 2009)

salvasol said:


> Yes I understand, what I mean is that probably the XO/electronic board (if there's one) inside the sub are designed to represent a series or parallel connection to the AVR when using a speaker...
> 
> e.g.: Sub alone 6ohms (that's what i found out online, but you mention 8ohms)
> Sub + speaker: series 6+8= 14 parallel 6+8/2= 7 :huh:



I will check the labeling on the sub again and see if your right. Maybe it says 8 ohm speakers only.


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## vicdog (May 5, 2009)

salvasol said:


> Can you explain Why not???
> 
> I have a pair of speakers wired in parallel, and they work fine .... :blink:


Parallel I can see, series seems like a shoot as to what comes out of each speaker. If the impedance of each speaker is not exactly the same, one could be much louder than the other. I'm just trying to understand what the pros and cons are.


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