Several useful training videos on the proper test and measurement set up for audio quality in portable media devices have been produced by Cirrus Logic and cover the following topics:
The basic equipment and source material needed to properly measure portable media players
How to correctly define the test set up and load conditions
Some basics of audio tests
How to figure out what power levels to target in order to measure the player's full potential
Which data you should take and how you can compare it between devices on a level playing field
The first video (9:38) begins with an introduction to the basic equipment and source material needed to properly measure players, as well as an explanation of several standard audio measurement specifications:
The second video (10:25) includes a discussion of measuring THD+N vs. Power and measuring THD+N changes over different volume settings:
The final video (8:22) shows how to calculate the dynamic range of a player from its THD+N vs. Power plot, and how to run a frequency response sweep:
