Song sounds heavily compressed when transferred to my laptop via email

I've written a song I'm pretty pleased with and it sounds great through earphones on my iPhone, but when I export it via email and listen back to it on my laptop, there seems to be much heavier compression going on, making certain vocals difficult to hear against the bass drum sound.

Would another method of exporting help or is there anything I can do to the song prior to export that will reduce this problem?