Placing outdoor speakers

Can I use this on an exterior wall to allow me to run the speaker wire through the wall, to another unit of the same, then connect to the amp? It will be attached to an electrical outlet box that’s rated for wet places. Or should I put a faceplate on it, run the wires through the cap on the top of the box and silicone around it?

I don’t recommend driving the subwoofer from the same amplifier as the L/R speakers. Use a dedicated amplifier for the subwoofer. Your suggested connection scheme will present a lower than desired impedance to the amplifier, there is no high pass crossover for the L/R, and the sensitivities for the subwoofer and L/R are different with no practical means to adjusting the relative levels.

Some will argue that the very lowest frequencies are presented in mono, therefore a mono feed to the subwoofer is no big deal. This was true for the very lowest frequencies when mastering LP’s, but this is not the case with other media. This subwoofer handles frequencies that are higher than would have been given this LP special processing and the stereo image will be a little strange.

I don’t recommend using these banana jacks to pass through an outside wall.

Ok thank you for all that. Would you use them on an interior wall, and what would you do to seal where the wire comes through the exterior wall? It’s going to be a straight through hole. 

I have these two different options. The grey conduit thing (I’m exhausted and the name escapes me) I could drill a hole through the top cap, run my wires and then silicone around the hole/wires. And then I was going to glue it to some conduit, and silicone where it meets the wall and enters. 
 

The white electrical box, I can do the same thing with. Run conduit to it, silicone it, and drill a hole through the top plug, run wires and silicone. 

Or I could just punch the hole in the wall, pass the wire directly through and silicone them around in the hole. 

Wall is metal siding over 6-8” logs. 
 

Running the gray plastic conduit through the exterior side of the wall, make sure to put a fitting inside the wall to secure it to that exterior wall is the way I’d go. At the top I’d come out the bottom of the box instead of the top, that minimizes water intrusion if the seal fails.

Coming out the side of the box with a downward facing elbow would work too. Get one designed to transition from the box to just wire, it will have an internal gasket.

Inside you can use a low-voltage setup, box or just a ring, if you use one designed for retrofitting you can just cut the hole, do the outside wall and then slip the box in. The speaker binding posts would be fine there. That is what I have here in several locations and it is handy to be able to remove the wires for painting or cleaning.

Water will follow a wire and tend to run into anything it can. Stanley_4’s technique inserts a “drip loop” near any wire entrance and any water flowing along the wire will drip off the bottom of the loop rather than running into something. Never drill a horizontal hole through an outside wall, always angle such that water will run out of the hole, not inside the wall.

So I’ll get an amp for the sub. Can I use my sonos amp to send a signal to the sub amp to play the music its speaker out to a speaker in on the sub amp? Then wire the speakers from the sub amp? or will I need to add a sonos port to the sub amp?

AMP provides a line level subwoofer output, PORT does not. AMP provides seamless powered subwoofer integration

Ok. But if I am going to get an amp specifically for the sub, an amp that is not sonos, how am I going to get it to play the music it is supposed to with the speakers it is supposed to? I can’t seem to find an OUTDOOR powered sub.