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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
ghdprentice
6,471 posts
 

There is bass output in both left and right channels, so you want to use both left and right channels to the sub.

Also, you do not want to use the tape out as it is unattenuated. You want the volume sent to your subwoofer to vary with the volume set on your preamp. If there are not two sets of output on your preamp. You can get a splitter that connects directly to the back of the preamp.

 

LFE is for Home theater. A different animal.

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
687 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.

 

 

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