Smartphones and tablets provide many ways to route audio output. The primary output paths include the earphone (headphone) jack, the built-in speaker and earphone, HDMI, and Bluetooth. In addition, there may be intermediary serial digital or analog test points inside the device that can be accessed. This technote looks at how to make connections and test the sound quality of each of these different output paths.
The accompanying APx project and test signal files may be downloaded at http://ap.com/display/file/590.
