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Connecting dual subwoofers to a stereo preamp

I have a 2 channel Adcom preamp. There's no subwoofer output (LFE or otherwise). For many years I've run my single M&K subwoofer with a double RCA cable, left to left and right to right from the tape outputs on the preamp. My 25 year old subwoofer is failing. I'm probably going to get a pair of SVS SB 3000 subwoofers. I've read quite a bit of opinion on whether or not to run dual subwoofers in stereo. I'd like to try it just to hear how it is then I'll decide. The SB 3000 has line in left/right RCA connections. If I don't set them up in stereo I know how I'll connect them. Not a big deal. But if I decide to hook them up in stereo then I'm not sure. I think I know. There's really only one way. I'd run the left output of the preamp to a Y and then run the Y to the left/right of the left subwoofer. Then I'd run the right output of the preamp to a Y and then run the Y to the left/right of the right subwoofer. I'm not asking about whether or not stereo subwoofers make any sense. I know the arguments here. I guess my question is, is there any actual problem with Y'ing the single channel of the output from the preamp to both the left and right on a single subwoofer? Should I even bother with Y'ing them? Maybe it makes more sense just to run to the left RCA on each subwoofer and leave the right subwoofer RCA connector open.

Thank you in advance and please excuse my terrible drawing! :)

 

 

udo
udo OP
8 posts
 

Thank you for your response.

Yep. I know what LFE is.

I was mistaken. My preamp has main1 and main2 out. I use Main2 out for my subwoofer. There are not two sets out outputs that I can use. It’s exactly as I show in my drawing except its not tape, it’s main2.

Using both left and right from the preamp to EACH sub defeats the idea of stereo subs. Other than the "tape" error in my drawing, should my schematic work okay? I have the little splitters you’re talking about. I’ve used them for other setups. But again, that would null the stereo idea to the subs.

Do you follow me?

fastfreight
688 posts
 

Send L output to left input of left sub.

Send R output to right input of right sub

Only need a y splitter if your preamp has only one sub output.

udo OP
8 posts
 

The documentation for the SVS SB3000 implies that if you connect a cable to only the LFE (right) RCA jack then the sub assumes you are using an LFE output from a processor. I could be wrong about that. Their documentation is not great.

 

Although in one spot it says this: "- Push repeatedly [the "+" button] or long press to increase volume, raise the low pass frequency cut-off or to set to LFE, or to increase Phase degree" so I’m not 100% sure.

 

 

blisshifi's avatar
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blisshifi
1,124 posts
 

@udo I own two SVS SB-4000s. You do not need the Y-splitter. Just have the left out going into one input on the left sub and the right out going to another input in the right sub. The only time you need a splitter going direct into sub is if you only have a single sub and your preamp only has a mono out to connect to it. 

udo OP
8 posts
 

Thanks @blisshifi. That helps. I had a feeling that would work.

I'm still hemming and hawing about whether to hook up 2 in stereo or not and even whether or not to get 2. I've had one nice sub for a long time and I've never been unhappy with it (my M&K V125).

I'm considering just getting one SB16-ULTRA for now and running it just the way I've been for years. When I have a more flexible budget, if I feel the need, I'll get another SB16-ULTRA.

My 20 year old Nautilus 805's are still amazing along with the rest of my gear (Rotel amp and Adcom preamp) even without a sub but they really do need it and when you're used to it it's a bit of a drag when you have to go without!

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