How to best connect odd number of small subwoofers to amp(s) to get best load config - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 5 Old 10-05-2019, 08:03 AM - Thread Starter
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How to best connect odd number of small subwoofers to amp(s) to get best load config

I am trying to figure a way to connect 7, 4 ohm, subwoofers to an amp or two amps for my new BOSS platforms (1 per chair, 7 total). I have several amps that I could put in bridged mode and just run all 7 drivers off a single amp. However, I'm not sure if that is the best way. I don't mind if all 7 have the same exact same level and each chair feels the same.

My main question is if I connect 4 in series as a group (16 ohms), then 3 in series as a group (12 ohms), and then connect those two groups in parallel, I should get about 6.85 ohms. That's in the sweet spot for the amps I'm looking at using. However, will the group of 3 subs be "louder" than the group of 4 due to their lower total impedance as a group (12 vs 16 ohms)? If that is the case, which wouldn't be ideal, I'd be interested to know if anyone has a better way to do it? The issue I know is having a group of 3 and 4 vs having two groups of 4 drivers. If I do it in a stereo configuration instead, and run the group of 4 as a parallel/series connection (4 ohms total load) then I'd be great. However, with the group of three, in series they'd be a really low impedance (a bit too much power for the subs), and in parallel, I think too high an impedance (a bit too low power). My last resort option would be to just pair 6 of them up for 3 sets of 2, each pair in series, for 8 ohm loads per pair, and then just run the final single driver on its own and adjust the input gain accordingly to match the other 6. But then I have to use two amps and split my sub output from my AVR an additional time to feed two amps (4 total channels), which might be fine, but also could introduce noise.

Any insight on how to best manage this dilemma of connecting 7, 4ohm, subs would be appreciated!!

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post #2 of 5 Old 10-05-2019, 02:16 PM
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This is a tuffy. Can you sneak in one more driver for an even number? Otherwise your 1st idea should work. I agree, use one amp though.
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post #3 of 5 Old 10-05-2019, 05:20 PM - Thread Starter
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Quote:
Originally Posted by Jk7.2 View Post
This is a tuffy. Can you sneak in one more driver for an even number? Otherwise your 1st idea should work. I agree, use one amp though.
So I had a revelation today, which I think solves the issue. These are the subs for my BOSS platforms, so they are smaller and won't have a lot of power fed to them. I realized I have a Kicker 10" sub in a box, which I had in my truck for a while. It's a 4 ohm driver, and the sensitivity is pretty much the same as the JBLs. So I'm going to try adding that into the mix as a NF behind my center seat in the front row, and even up the count to 8. I am hopeful that will work. If it doesn't, then I may just purchase another JBL and built some type of box or something for it, or add it as a second driver in the BOSS for the MLP. I know many guys are putting two drivers per seat, so that might be a great option anyway. We'll see. Hoping to have the platforms built and painted tomorrow!

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post #4 of 5 Old 10-06-2019, 02:51 PM
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Quote:
Originally Posted by luv2fly3 View Post
So I had a revelation today, which I think solves the issue. These are the subs for my BOSS platforms, so they are smaller and won't have a lot of power fed to them. I realized I have a Kicker 10" sub in a box, which I had in my truck for a while. It's a 4 ohm driver, and the sensitivity is pretty much the same as the JBLs. So I'm going to try adding that into the mix as a NF behind my center seat in the front row, and even up the count to 8. I am hopeful that will work. If it doesn't, then I may just purchase another JBL and built some type of box or something for it, or add it as a second driver in the BOSS for the MLP. I know many guys are putting two drivers per seat, so that might be a great option anyway. We'll see. Hoping to have the platforms built and painted tomorrow!


I think adding the extra jbl driver for a second in the BOSS platform for the mlp would be the best solution. It solves the problem and adds more feel to the money seat.
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post #5 of 5 Old 10-07-2019, 01:53 AM
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Quote:
Originally Posted by luv2fly3 View Post
My main question is if I connect 4 in series as a group (16 ohms), then 3 in series as a group (12 ohms), and then connect those two groups in parallel, I should get about 6.85 ohms. That's in the sweet spot for the amps I'm looking at using. However, will the group of 3 subs be "louder" than the group of 4 due to their lower total impedance as a group (12 vs 16 ohms)?
Yes - The group of 4 subs would get approx. 10% power each and the group of 3 would get approx. 20% power each - so definitely louder.


Quote:
Originally Posted by luv2fly3 View Post
So I had a revelation today, which I think solves the issue. I realized I have a Kicker 10" sub in a box, which I had in my truck for a while. It's a 4 ohm driver, and the sensitivity is pretty much the same as the JBLs. So I'm going to try adding that into the mix as a NF behind my center seat in the front row, and even up the count to 8. I am hopeful that will work.

You won't be feeding this sub enough power. The JBLs in free air will only take 80w max (from memory of reading the BOSS thread) and I'm pretty sure your boxed Kicker will need more than that.

Do as suggested above and stick the Kicker as a 2nd driver under the MLP. Just make sure you model it in WinISD to make sure it can take the same power as the JBLs.
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