I want to add that what is in your control is:
1) Controlling the size of your audio files (naturally if you add a huge audio it will take longer to download).
2) Consider cutting a longer background music audio into half or smaller piece.
3) Consider abandoning the specific music you like and go find another which is much smaller size.
4) Use various tricks to keep the player busy while the audio is loading, such as:
>> Start by showing various game controls
>> Have a couple of pictures of story. Even 1-2 seconds that the player looks at the story and clicks NEXT adds up to 10 seconds for 3-5 story pics.
>> Have some settings page giving the player a choice to set volumes or pick colors or whatever. Could be any not-so-important stuff just to buy some seconds for loading.