# Series Parallel for subw and speakers OK?



## Heinemusagain (Apr 19, 2018)

I know this gets asked often...but here am I again.
I have an old stereo receiver with no subwoofer outputs. The subwoofer will connect as per instructions to the B speakers of the receiver, but the unit is so old I cannot play both A and B together..that is how JVC made it.

Now I am familiar enough with wiring to know how to wire the speakers plus subwoofer in series parallel so that each is at 16 ohms. Any problems foreseen. Actually I don't care if I blow up the receiver, ...just don't want to damage the speakers or subwoofer.
Thanks for any ideas.

aha... a little wrinkle...the specs for the sub show 22 ohm impedance. so parallel series on a normal set up would be 44 ohms....but in a subwoofer, am I thnking right?


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## w0j0 (Dec 29, 2017)

I don't think this is going to work the way that you desire it to. A better solution to drive your subs would be to pick up an amplifier with built in crossover that can accept speaker level inputs. Class D amps have gotten cheap and you'll obtain acceptable results by feeding only frequencies that the sub can handle to it. This is about the only way that any sort of balance can be obtained between the speakers in your system.

Sent from my SM-J700M using Tapatalk


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## Heinemusagain (Apr 19, 2018)

w0j0 said:


> I don't think this is going to work the way that you desire it to. A better solution to drive your subs would be to pick up an amplifier with built in crossover that can accept speaker level inputs. Class D amps have gotten cheap and you'll obtain acceptable results by feeding only frequencies that the sub can handle to it. This is about the only way that any sort of balance can be obtained between the speakers in your system.
> 
> Sent from my SM-J700M using Tapatalk


Yes, I know what you mean. I have two massive 15 inch subs on another system that I power this way with a dedicated amp and an active crossover circuit box.

However, the little Jamo sub also has frequency response controls and volume control, that may allow me to teak the sound enough.


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## w0j0 (Dec 29, 2017)

Heinemusagain said:


> Yes, I know what you mean. I have two massive 15 inch subs on another system that I power this way with a dedicated amp and an active crossover circuit box.
> 
> However, the little Jamo sub also has frequency response controls and volume control, that may allow me to teak the sound enough.


If these subs you speak of have a volume control, then you probably plug, too, yes? If so then they already have an amp built in and as active subs. Active subs usually accept line level inputs with some capable of speaker level inputs(this is what you're looking for). If your model does not accept speaker level inputs, fear not--you can use a voltage divider network to knock the speaker outputs of your receiver down to line level for your subs to use. A voltage divider is simply a network of resistors and can safely piggyback the connection of your full range speakers, or plug into the "B" outputs.
https://goo.gl/images/b25WcZ
Hopefully the above link shows a 10k resistor in series with a 1k resistor, across the speaker outputs and the 1k resistor is in parallel with the line level input. 
I think you may also find that the spec in your OP is 22k ohms instead of 22 ohms. 22k is more likely a line level impedance than 22 ohms is a speaker level impedance.
Hope this helps


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