Calls are generally private conversations so the challenge would be to make a speaker that would not let everyone hear your conversation and then when playing media allow for a wide audience. For now the solution is two or more speakers.
Is there a reason why the phone cant just have the one speaker on the top used for calls and music? And is there a way to force the phone to play music from both? Cause im geussing it would be louder?
Maybe its obvious but it worked before, having just one speaker for everything