Been meaning to post this a while. I had single speaker set up that sufficed in our 2012 Encore, but that got backed over in my work parking lot.
Small changes from the '12 Encore to '13 D'Lite replacement forced me to rethink things, and it worked out pretty well. The newer configuration would also have worked on on the '12 Encore (and I'd guess most recent Burleys). Without further ado...
Parts needed include:
1) Two battery powered speakers. I have used Altec Lansing iM227 Orbit MP3 Speaker
, though there may be other options on the market at this point.
2) Two 3' 3.5 mm speaker extension cables Amazon.com: 3' 3.5mm Male Right Angle to 3.5mm Female Gold Stereo Audio Cable, Nylon Reinforced, Premium Quality Cable: Electronics
3) Stereo to mono splitter Amazon.com: HOSA STEREO 3.5mm PHONE (M) - TWO MONO (1-TIP AND 1-RING) 3.5MM (F), 6 in.: Electronics
4) Cable ties, forget if I used 6" or 8", but definitely the black ones (UV resistant).
5) 2 hose clamps, one for each speaker. Can't recall exact sizing, but take the speaker to a hardware store and you'll find what you need.
6) mp3 player. I usually use Sansa Clips (we have a couple), but the pocket in the Burley trunk is large enough to accommodate a smartphone or larger.
Here's looking in, two speakers, left and right channels. The whole set up stays in place even when folding the trailer down and setting up, and has almost a year on it at this point with no issues:
Speaker sockets with and without speakers:
What the speakers will plug into (1 on each side)
Some shots of the trunk, cable routing, etc.:
1) Just loosen the hose clamps a bit to pull the speakers out for battery changes, then tighten back in place. Works well.
2) Unless you're an electrician or telecom worker, chances are when you cut the cable ties for installation they will be SHARP. Either sand, melt, or search youtube for making clean cuts with Klein Dykes.
3) The stereo to mono splitter is key to getting true stereo sound, rather than 2x mono. Assuming the input signal is stereo.
I can clarify or post additional pictures if it would be helpful.
** Mods, if you could correct thread title spelling, that'd be great.