The HPToy is wireless DSP control of PowerDAC V2/V2.1.
PowerDAC V2.1 is the worlds first true digital USB 24/192 0.6W balanced/unbalanced headphone amplifier.
The app allows controlling of plenty of DSP functions in an intuitive manner. Yep, complex things getting easier today: Crossovers adjustment, parametric EQs, bass and treble, loudness, compressor, preset sharing, and more.