It supports stereo headphone and stereo line level output, as well as stereo line level input or mono mic input.Teensy Audio Library lets you use input and output simultaneously along with a toolkit of audio editing objects to easily create all kinds of sophisticated audio applications. You can play multiple sound files, create synthetic waveforms, apply effects, mix multiple streams, and output high-quality audio through headphones or line-out pins.Teensy 3.x have the Cortex-M4 DSP instructions, which provide plenty of processing power for real-time FFT (spectrum analysis), opening up the possibility of creating advanced sound-reactive projects.Two of these 14x1 pins can be used to easily solder the Teensy 3.x and audio board together. They can be connected together via a 14-pin female connector and a 14-pin male connector.