# Adding 2nd Subwoofer Question



## dustwvl (Aug 20, 2007)

I am going to be adding a Ultra X-12 to my LFM-1 plus and I have a couple questions.

1) I will be running them from my Pioneer SC-77 Receiver - My plan to minimize the amount of cables needing to be run (my subs are in the back of the room) was to just run them from one subwoofer out with a y splitter. Does it matter where that Y splitter is at? Can I run one cable to the back of the room and then split it to the two different subs instead of doing the y at the receiver?

2) As far as setting them both up, I know I need to set the level indepedently ( I have not been using MCACC) but what about phase setting? They will be symmetrical to the listening position.

Thanks,


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## tonyvdb (Sep 5, 2007)

Given they are two different subs it will be somewhat difficult to blend them together correctly. You will be limited by the weakest sub as to output. 
Yes, you cna put the splitter anywhere you feel works best.


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## dustwvl (Aug 20, 2007)

Yeah I was hoping to get an identical sub but they were sold out. I am hoping they will be close enough. I am wondering if running the weaker in max output and the stronger in max extension would help.


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## willis7469 (Jan 31, 2014)

I have a similar arrangement. I run a single cable up to the first sub, and split at that point. You'll need double female rca to do this way after the split but I never trusted the "out" stage from the sub amp to be exactly the same. Seems like since I joined I've been saying this, but Tony is right. Integration is not impossible, but will be more difficult with 2 different subs. Your questions about level and phase are good ones, and ime, phase is the most important relationship when setting up multiple subs. This was an interesting process for me, and I'd be happy to offer anything useful to help. I'm running 7.3 and I don't have my minidsp yet but have fortunately achieved a pretty nice graph.


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## dustwvl (Aug 20, 2007)

willis7469 said:


> I have a similar arrangement. I run a single cable up to the first sub, and split at that point. You'll need double female rca to do this way after the split but I never trusted the "out" stage from the sub amp to be exactly the same. Seems like since I joined I've been saying this, but Tony is right. Integration is not impossible, but will be more difficult with 2 different subs. Your questions about level and phase are good ones, and ime, phase is the most important relationship when setting up multiple subs. This was an interesting process for me, and I'd be happy to offer anything useful to help. I'm running 7.3 and I don't have my minidsp yet but have fortunately achieved a pretty nice graph.


Thanks. Anything you can offer as far as help setting up phase is greatly appreciated. Thanks again.


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## jefferytammy (Sep 30, 2012)

I just installed an identical sub at the rear center of my room to compliment the front center one. They are recieving the same signal from the reciever via. wye connection. The forward faceing 15" subs are set at the same levels for now. The only difference is phase control switch. The front is at 0 to match the four main towers and the rear sub behind the couch is set to 180.
In all it shakes pretty good but Id like to learn more about optimizing the lfe on the reciever opposed to the sub control.


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## willis7469 (Jan 31, 2014)

jefferytammy said:


> I just installed an identical sub at the rear center of my room to compliment the front center one. They are recieving the same signal from the reciever via. wye connection. The forward faceing 15" subs are set at the same levels for now. The only difference is phase control switch. The front is at 0 to match the four main towers and the rear sub behind the couch is set to 180. In all it shakes pretty good but Id like to learn more about optimizing the lfe on the reciever opposed to the sub control.


 Do you have an SPL meter? If they really are at the same level (on the sub), you'll be experiencing the rr sub much more than the the front.


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## willis7469 (Jan 31, 2014)

If you have an SPL meter, I'd turn off the rear sub and set the front to 72db with the gain knob on the sub (if you like em hot, set both for 75 for combined around 80-82. This of course will be to taste). Then turn off front sub and set the rear for 72db on sub (or flavor), then turn on both and set the level you want with the avr. A good place to start is say -7. You'll want this done before doing it on the subs. If you get much into the +, you can introduce distortion into the signal. You'll also probably find the gain on the front sub to be up to 50% higher than the rear. I'm guessing even with 2 subs, the rear one is slightly localizable due to the higher gain. This will go away once your balanced. Then phase.....


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## willis7469 (Jan 31, 2014)

Oh, if you don't have an SPL meter. Get one.


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