Delete icon res/drawable-ldpi. Android system can generate it by downscaling hdpi.

Reference
https://developer.android.com/design/style/iconography.html
Replace default icons with custom ic_launcher.png icons.

Started with Adoibe Illustrator artboard 1024x1024, exported png 1024x1024 24 bits with alpha transparency.
Then used web site Android Asset Studio / Launcher Icon Generator to generate icons.
Chose bevel effect. (and inset? or was this automatic?)
Also generated web icon 512x512 for possible use in app store.
Reference
http://android-ui-utils.googlecode.com/hg/asset-studio/dist/icons-launcher.html#foreground.type=image&foreground.space.trim=0&foreground.space.pad=0&foreColor=33b5e5%2C0&crop=1&backgroundShape=bevel&backColor=ffffff%2C100