Herschel Supply has some really nice backpacks that I think you'll like. I personally own one and love it since it has a holder for your laptops/ipads. Speaker wise, it doesn't come with it, but it has a internal media pocket so you can stick your ipod in the pocket and your headphones through the hole.

<div id='prev-mm' class='mm-img'><a href='https://s.yimg.com/hd/answers/i/82f03e81445d42d9aacca0b80950d6e9_A.jpeg?a=answers&mr=0&x=1407139043&s=2018b12cc6211737e59e71d2576df499' rel='nofollow'> <img width='392' height='221' src='https://s.yimg.com/hd/answers/i/82f03e81445d42d9aacca0b80950d6e9_A.jpeg?a=answers&mr=0&x=1407139043&s=2018b12cc6211737e59e71d2576df499'/></a>

This is the sprayground "rython" back pack. Its out of stock on their website but if you google the backpack you can find ither sites. It has a laptop and ipad holder. I dont know about anybackpacks with speakers but im sure you could fit a small speaker into one of the compartments

<div id='prev-mm' class='mm-img'><a href='https://s.yimg.com/hd/answers/i/7ba060829ee24250bbf8ac496806066b_A.jpeg?a=answers&mr=0&x=1407139043&s=8d96d83ef64b5cdd7eb9103f81ce15d4' rel='nofollow'> <img width='392' height='221' src='https://s.yimg.com/hd/answers/i/7ba060829ee24250bbf8ac496806066b_A.jpeg?a=answers&mr=0&x=1407139043&s=8d96d83ef64b5cdd7eb9103f81ce15d4'/></a>