That’s actually really cool that you made your own panels. From what I have read about blocking noise, acoustic panels mostly help the sound inside the room but they don't really block noise from getting out or leaving the room. Hearing the music outside, probably would be more about soundproofing. Things like sealing gaps under doors, fixing windows, or hanging heavy curtains would help more with that.
You don’t need to scrap the panels because it still help with echo, they're still doing their job by reducing echo in the room. Keeping sound from escaping just needs different, heavier materials than fabric panels.