Getting custom ringtones is no longer as popular as it once was, but that's most likely because finding them is easier than ever. Surprisingly, the market for Android apps for finding ringtones, notifications, and alarms isn't as vibrant as one might think. There are only a handful of applications with this capability these days. However, you have several options.
You can do things like trim songs, mix music, and create your own ringtones, notification tones, and alarms. You can also add things like fade in and out effects for a cleaner presentation.
Some other features include variable bitrate support, support for most popular music codecs (including WAV, FLAC, OGG, and more), and you can even adjust the volume. It hits most of the correct notes and is a good option for creating your own tunes.
The music side of the app includes a five-band equalizer, metadata support, themes, backgrounds, and a great user interface.