Portable/bed speaker ideas?

I have a 2nd gen DC and am looking for your creative ideas and experience to help me come up with something that can serve as an occasional in-bed speaker.

We're fortunate to have a drive-in theater in the area when there are so few left, but the audio is transmitted via FM radio and you can't hear much from the stock radio while sitting in the bed of the truck. I'm looking for creative speaker options as well as creative ideas for connecting the temporary speakers for our once- or twice-a-year trip to the drive-in movie with the kids.

Thanks!

 

Easy solution would be a long AUX cable and bluetooth speaker like the JBL charge 2.

 

I'd be ok with that (I have the small bluetooth speaker from Bose with an aux input) but I thought the aux jack for our radio was aux input, not aux output? Am I misunderstanding?

 

I'm pretty sure JBL sell amps and speakers that Bluetooth connect to each other so you don't have to run wires

 

You're right I'm retarded haha. Ok I got it, AM/FM reciever app for your phone, bluetoothed to your mobile speaker.

 

Interesting idea, I'll look into it, thanks!

I considered using an app but based on what I understand the frequency is locally broadcast by the theater, not an FM channel broadcast on the internet.

 

Ah I didn't know how that worked. I assumed our phones could pick up FM directly.

 

You could just buy a radio also