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

Go dual, you will never regret it as long as you place them correctly. In my experience, do not place them by the mains just because you want stereo. Place them on different walls. One behind the right speaker and one a third of the way down the left wall is my setup. They still play perfect stereo and give you clean bass at any position in the room. Placing them by the speakers results in heavy boomy bass along the back wall, at least in my house of stereo and it is heavily acoustically treated. That was one of the best tip I got on this site. Wish I remember who it was to thank them.

What you’re doing isn’t clear to me, but it looks like you’re combining the left and right channels together at the amplifier output to create a mono signal for your sub. Is that correct? If so, the problem I see is that most amplifier and preamplifier outputs are wired in parallel. So if you tie the L and R outputs together at an amp output, you’re likely to have mono signals at the amp's other outputs, too.

Thanks for all the input everyone. I think I'm going to go with 1 sub for now. I'd like to use 2 but I want to spend some decent money on them and right now, while renovating my new house (well, old house, new to me) my budget is too tight and I'd rather spend more than a grand per sub. I think I'll one the SVS SB16-ULTRA for now like I mentioned above and then in several months when things have settled down I can get another. 

@cleeds - no, that's not correct. My schematic doesn't show that. I'm not combining the L/R at the preamp. I'm sending L to one sub and R to the other. But I'm not going to do that now. I'll revisit all this later. With just one sub for now, the connections are a no brainer. Just what I've been doing for the last 25 years with my M&K.

@hifibliss - my room isn't as big as yours. It's only 14' x 17'. It's an okay size but I think 4 subs would be too much and like I said above, it's not in my budget. Ideally after I have 2 nice subs I'll upgrade my mains to a full range pair. I used to have a pair of Nautilus 803's but had to sell them 20 years ago for financial reasons. I really miss them. I have to do some research when I get new mains but I've wanted pair of B&W 802D's lately or maybe 803D's. We'll see when I get to that point.

Thanks again everyone!