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Discussion Starter · #1 ·
I am getting ready to install three Infinity Kappa 1000W 10” subs and I have a question about the wiring and ohm load. I have an Infinity Kappa One K amp and although it is a mono amp, it has two sets of sub connection terminals.

I had already done some research on the different wiring options and the resulting ohm loads, and I was prepared to set all subs at 4 ohms and wire them series/parallel for a final ohm load of 2.3 with all subs getting equal power. My personal preference would be an even ohm load, but I understood why that is not possible with an odd number of subs… or so I thought.

I was reading the Amazon comments for my sub today and one guy claims to have achieved an even 2 ohm load by setting one sub at 4 ohms and connecting it to one of the amp’s terminals and then setting the other two subs at 2 ohms and series wiring them into the amp’s other terminal. He claimed that since the amp terminals were internally paralleled the two 4 ohm loads would work out to an even 2 ohms with each sub getting equal power.

Since I don’t fully understand the purpose for two terminals on a mono amp, I have no way of knowing if what he says is true.

Can someone explain?
 

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Discussion Starter · #4 · (Edited)
The purpose is only to make wiring easier. If you have a "bank" of multiple subs you have more terminals to fit all the wire on.




I'm not sure how you get 2.3 Ohms from a series/parallel of (3) 4 Ohm subs? Perhaps you meant 2.6 Ohms?

IIRC the switch on those subs aren't EXACTLY 2 or 4 Ohms? There's some amount of play. So I would expect a different final impedance from the series string vs single sub string in that Amazon post. You could measure to verify but that's still a DC nominal measurement. You be the judge but if the subs are sharing air space then I would parallel them all.
You’re correct. I had 2.3 in my head, but the Crutchfield drawing showing the series/parallel wiring scheme says 2.7.

I haven’t seen anything about the switch not being a true 2 or 4 ohm. Maybe Infinity does something similar to their smaller speakers where they are actually 3 ohms because they factor in the resistance of the wire?

Each sub will have its own chamber with .80 cuft of airspace. If I parallel wired them, the resulting ohm load would be 1.3 and I don’t believe that amp is stable below 2 ohms. Even at 2.7 the amp will be putting out 850 RMS and the subs are rated at 450 RMS. I’d prefer the amp to run as cool as possible. I’m actually a little apprehensive about how hard three subs are going to slap. I’ve never had more than one.

I really appreciate the detailed response!

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Discussion Starter · #7 ·
You shouldn’t wire anything like the above pic, it won’t give the same power to each driver, and the guy who said he did just that is wrong also…

3 is a really odd number unless you can run a 1 ohm stable amp

Put bluntly you have the wrong subs for your amp

With three subs you need either all subs in parallel or all subs in series

So 4ohms a sub is either 12 ohms or 1.33

2 ohms a sub is 6 ohms or 0.667

That’s it for three subs to get the same power to each driver 👍🏼 You can’t series/parallel 3 coils and get equal power to each ever
Wow that’s surprising! I’ve never known Crutchfield to publish errant info, but I trust your expertise. I’m so far into this build and over budget unless I can sell a couple of components. I’m not cool with a 1.3 or 6 ohm load, so I’ll downsize to two subs. Luckily I have only purchased one sub and a single sub enclosure. I was planning to buy the other two subs and the three sub enclosure on Friday.

I really wanted to run three, but I’ll make due with two and come up with another plan for later.

Thanks for saving my sanity and my pocketbook!
 

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Discussion Starter · #9 ·
The leg of the circuit with sub 1 & sub 2 in series will add to an 8 Ohm load. That will draw less current (half) than the single 4 Ohm leg of sub 3 by itself. Also, subs 1 & 2 will be sharing the voltage potential across sub 3 by itself, cutting the voltage to sub 1 & sub 2 in half. So sub 3 will be working much harder than subs 1 & 2. I would choose a different wiring scheme or amp. I’ll look into the switch.
Thanks! I want this done right, which means each sub has to get equal power and the total resistance has to be within the specs for my amp without going over 4. Two subs will ruin my hearing and beat the block up just fine for now.

‘Preciate the help!
 
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Discussion Starter · #11 ·
That diagram makes my head hurt.

anyway you could always just buy a 4th sub and make it an even 4 ohms :) or sell the 3 10’s and buy 2 12’s.
I could do a lot of things, but it’s time to finish this build and start enjoying my car and this weather. I have a simultaneous soundproofing project in progress and I haven’t driven my car in almost 3 weeks. You know as well as I do… the build is never done it’s only complete.
 

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Discussion Starter · #14 · (Edited)
i am not sure how a speaker can be either 2 ohm or 4 ohm.
The Infinity Kappa subs have a switch allowing you to select 2 or 4 ohms.

Are you saying @dumdum is incorrect in his statement about equal power distribution? The only ohm loads that allow for equal power distribution with three subs are 0.67, 1.3, 6, and 12. None of those work for me.

The goal is not to end up with an even load. The goal is to have power distributed equally to each sub and maintain a load within the specs of the amp without going over 4. The Crutchfield diagram will not allow for that.
 

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Discussion Starter · #21 ·
Impossible with 3 subs.. you will be at 1.33 ohms with them on 4 ohm mode and in parallel... the alternative is series where the impedance doubles so you would be at like 12 ohms or something silly high..

you would need four subs to get to 2 ohms... or just use two subs and call it a day.
I’m not trying to be rude, but you quoted my post and then told me the same thing I just wrote.

We’ve already established the subs can be either 2 or 4 ohm. Don’t ask me how. That’s a question for Infinity and I’m guessing they’ve published documents explaining how it’s accomplished.

I’ve already stated twice that my amp is only stable to 2 ohms and my primary goal is to get equal power to each sub while maintaining a final impedance within the amps specs and without going over 4 ohms.

With all that in mind, my choices for final impedance are 0.67, 1.3, 6, and 12. Two of those are out of spec for the amp and the other two are above 4 ohms, meaning none of them work for me.

The Crutchfield drawing, while presenting a final ohm load within spec and under 4, does not distribute power equally because Sub 3 is wired in parallel while Subs 1 and 2 are series.
 

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Discussion Starter · #23 ·
This is why i was trying to figure it out how this sub works. I was thinking in my head D4, and 3 D4 subs would be 2.7ohms wired in parallel. So tell me please...this sub that can be wired to 4 ohm or 2 ohm....is that 4 ohm SVC and 2 ohm SVC? Maybe include a picture of the sub and a pic of the manual?
Yes they are single voice coil. The model number is Infinity Kappa 1000W if you want to look up the documentation. I’d love to hear an explanation of how the different ohm settings are achieved if you feel like replying back after you look it up. These subs are pretty popular because they’re being sold at a $100 price point and they are well built. Infinity seems to do things a bit different, but there’s science behind it. For example, their 6.5 full/mid range speakers are rated at 3 ohms because the wiring adds additional resistance to create closer to 4 ohms.

I’ve never heard a bad word about these Kappa subs. I appreciate your participation in the discussion.

Here’s a pic of the sub. The horizontal slider switch above the wiring terminal is your 2 and 4 ohm selector.

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Discussion Starter · #27 ·
3 S4 subs = 1.3 or 12....pass, wont work with your amp.
3 S2 subs = .66 or 6ohms.

So given all that you have said the only option that will remotely work with your amp is wiring them at 6ohms.

Not a fan of this set up at all.

Are you willing to change amps to get 1 that is 1 ohm stable?

If not go with 2 of them wired down to 2ohms.
The amp is rated at 1000 RMS @ 2 ohms and 700 RMS @ 4 ohms. The speaker is rated at 450 RMS, but they do not specify at what impedance. I assume 450 RMS @ 4 ohms.

I prefer my builds to run cool and play all day. For that reason I try to power my subs according to their RMS specs at 4 ohms and run amps that generate more power than needed. I don’t blow speakers or pop fuses, or fry caps, and I have some room to grow without having to make major changes or spend major money. That formula has worked for 30 years, so I don’t see a reason to change.
 

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Discussion Starter · #29 ·

Sonic says it has three coils.
Interesting. I can attest to the solid construction. The cone is extremely stiff and difficult to compress in a sealed enclosure. I’ve already been cautioned on the need for a proper break-in period.
 

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Discussion Starter · #33 ·
@nyquistrate and @dumdum,

Thanks again for stopping by to help me out. The thread went off the rails last night because no one bothered to read what y’all posted. One guy had me ripping my whole system out and running 12’s at half ohm. Sheesh! I’m fine with two subs.
 
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Discussion Starter · #35 ·
its not that we didnt read what those guys said, its that i had to figure out what kind of unicorn sub you had. And in the end i said the only thing that would work would be 2 subs. Just took me a little longer to get to that conclusion #papaold as my grand son loves to say LOL>
All good bro. I thought everybody knew about those subs. About the only thing I don’t like about them is the small amount of airspace recommended for a sealed enclosure. It’s hard to find prefab boxes with .60 cubes per sub and a mounting depth of 6 11/16”. I ordered a box with .77 cubes per sub.
 
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