Sub wiring help.

[J216 10+ year member]

OK, I already have 2 8 ohm subs wired in parallel. I want to add another 8 ohm sub in parallel. Unfortunately, I can only find the 4 ohm version of the sub that I'm looking for.

Is it OK to mix the impedance? Or, Is this a recipe for disaster? If they are all wired in parallel, Will it end up at 2 ohms?

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[polyrhythmic81]

umm...i'm not sure, but if what i learned in circuits class applies directly here (meaning the impedance is purely resistive), your equivalent impedence will be 2 ohms ( 1 divided by (1/8 plus 1/8 plus 1/4). however, the 4 ohm sub will still get twice the current (and dissipate twice as much power) as the other two subs.....weird. If the impedence is partly reactive, calculating the equivalent impedance is going to invlolve some complex algebra...

 

[JLranger 10+ year member]

run your amp from one channel, if you do this and run a chain of speakers yes with three subs it will cut the resistance down to two ohms. hopefully you have a two channel amp your doing this with.

 

[IDSkoT 5,000+ posts]

umm...i'm not sure, but if what i learned in circuits class applies directly here (meaning the impedance is purely resistive), your equivalent impedence will be 2 ohms ( 1 divided by (1/8 plus 1/8 plus 1/4). however, the 4 ohm sub will still get twice the current (and dissipate twice as much power) as the other two subs.....weird. If the impedence is partly reactive, calculating the equivalent impedance is going to invlolve some complex algebra...

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Normally I'd do the math, but it's 4 AM. So, I'm gunna pass.

OK, I already have 2 8 ohm subs wired in parallel. I want to add another 8 ohm sub in parallel. Unfortunately, I can only find the 4 ohm version of the sub that I'm looking for.
Is it OK to mix the impedance? Or, Is this a recipe for disaster? If they are all wired in parallel, Will it end up at 2 ohms?

It's not okay to mix impedance... the T/S parameters are different, thus will cause cancellation... not to mention, as he said up there ^^^, the sub with lower impedance would be getting more power.