Audio Sound Too Low in Android App

I recorded some audio files to use in my app, around 50, so I would like to not record all of them again. I recently used SoundPool to play the audio files on a real device instead of the emulator and you can barely hear them. On the emulator with my PC volume set to max and device to max, I can hear it fine. Should I try to record the files louder or is there another option?

Solution

I've found that when targeting mobile devices (and cheap/small laptop speakers for that matter), it is best to do two things to your audio:

Compression: I do not mean data compression, I mean dynamic contrast compression. This will remove some of the level differences between loud and soft parts of the recording, allowing it all to be heard better.
Normalization: When you normalize audio, you take the loudest part of the audio, and scale the entire audio clip up so that the loudest part is at the loudest that can be stored in the audio file.

You can do both of these easily with any audio editing software, such as Audacity.

Finally, you should also keep in mind the reproduceable frequencies on such small speakers.
Most of these speakers are built with speech in mind. Because of this, you will find that they tend to be the loudest in the 700Hz-2.5kHz range.

That is, if your sound effects are low in frequency (think bass), then it will be almost impossible to hear them on a phone's small speaker which cannot reproduce such low frequencies.

If you have more questions on the matter, please visit https://video.stackexchange.com/.