Question Need help connecting a subwoofer to a receiver without sub output

Jul 13, 2020
I just bought Klipsch R-120SW active subwoofer and I can´t figure out how to connect it to my Yamaha R-S202BL receiver that has no dedicated sub output. I keep hearing about speaker-level inputs, but have no idea what it is. Subwoofer manual states that it is possible to connect even without sub output: https://f072605def1c9a5ef179-a0bc3f...uals/Reference-Subwoofers-2018-Manual-v02.pdf
But I am not sure what cables to use and if it will even work.
Jul 13, 2020
I'm not an expert by any means, so take this with a grain of salt.

Long story short- unless you can find some special adapter, which I don't have any knowledge or experience of (but which very well might exist, I'm not an expert), then your sub and receiver aren't compatible.

Here was my thought process (including looking at your manuals):
Two things-

First, you might find something like a line out converter. I only know these from car stereo systems, which aren't interchangeable with home audio, but I believe they have some for home stereo. It will convert speaker wire outputs to a subwoofer output. Check that it can handle what your receiver is outputting though.

Second, to explain what speaker level input means, you will essentially tap into a pair of speaker wires (this is called splicing, lots of different methods/tutorials on how to do it, with or without products), and then take those wires into your subwoofer. So for example, if your subwoofer is positioned near your left speaker, you will splice one wire into the left positive, and one wire into the left negative. (If the speaker style is one where you just put the wire into a metal hole, and a spring/screw holds it in place, you can probably even just twist the 'splice' wire together with the speaker wire, and put them both into the same hole, but I'm not 100% certain on that, it wasn't an option with car speakers, with which I have experience). Essentially, what this achieves is the sound signal is travelling from the receiver and then out both new ends of the speaker wire. One goes into your speaker like normal, and the other goes into your subwoofer's high-level input harness/input (not sure if you have one, see below), which will be labelled left positive, left negative (likely with options for both left and right).

Here's the issue, though. Looking at the manual for your subwoofer, it doesn't look like it has a high-level input (speaker level input) option. Normally, it would have a harness that looks like this:
that plugs into a port like the one shown in the first picture on that link, or it would have plugs just like your speakers do, which can accept regular speaker wire. I don't think your subwoofer has that. That means that speaker level input isn't directly an option. You might find some converter, but I don't know exactly what that would be.

As far as what your subwoofer manual says, it looks like it has two options for input. The first is a single cable running from the receiver's 'sub out, or SW out' plug, into the subwoofers LFE plug. Unfortunately, your receiver doesn't have one of those. The second option is if your receiver has two 'pre out' plugs, left and right, which can then plug into your subwoofer's respective left and right. Unfortunately, your receiver doesn't have those plugs either.

On your receiver's manual, it says that it can be connected to a subwoofer via speaker level input. Unfortunately, your subwoofer doesn't have any way to accept speaker level input. Unless you can find some sort of adapter that can receive speaker level input, and convert it to something that could plug into your sub's L/R or LFE plugs, then I don't think they are compatible. Again, that adapter might exist, I just don't know either way.

I hope this was helpful, and that I made sense!
Feel free to reply/message me for clarification