I've never done this but have thought about it.
Parts Express has a simple and not too expensive possible solution.
https://www.parts-express.com/terk-lf30s-wireless-24-ghz-wireless-a-v-entertainment-expansion-system...
If I were you I'd just accept that in order to get really good, portable sound you need to get a portable player. I bought a Fiio x7 and it sounds great, is easy to use. It's kind of a hassle ripping CDs but worth it in my opinion. I hook it up to an old creek 5350SE connected to Vienna Mozart Grands in my camper and it's a great, very satisfying little system. I'd like to get some powered speakers to make for a very small/portable but still good system.
Parts Express has a simple and not too expensive possible solution.
https://www.parts-express.com/terk-lf30s-wireless-24-ghz-wireless-a-v-entertainment-expansion-system...
If I were you I'd just accept that in order to get really good, portable sound you need to get a portable player. I bought a Fiio x7 and it sounds great, is easy to use. It's kind of a hassle ripping CDs but worth it in my opinion. I hook it up to an old creek 5350SE connected to Vienna Mozart Grands in my camper and it's a great, very satisfying little system. I'd like to get some powered speakers to make for a very small/portable but still good system.