Overall volume too low/muffled after exporting song

Hello. I am using Garageband (version 2.0.7) for iOS 8.4 on an iPad Air 2. Everything sounds good in the mixer, but whenever I export a song (which I usually do just by sending it to myself via email), the m4a file I receive is extremely quiet and muffled. I never experienced this problem when I was using Garageband with my old iPad 2, but this is my first time using Garageband for my new Air 2 and it's been a while since I used Garageband in general.

I keep seeing people directed toward answers that apply to regular Garageband (in terms of "Auto-Normalize" in Garageband preferences or Master Track options), but I don't see any of those options anywhere in GB for iOS. Am I just not finding the obvious fix? Is there something else I should be doing? Any help would be appreciated. Thanks!