When you think about music on your mobile device, you might not think about the path that it takes. You use a Digital copy of a song that the phone or tablet converts to an analog signal through the on-board processor, that is transferred over your headphone jack to play on your headphones. Any one of these can be an issue. low quality recordings will sound poor, as will poor digital to analog converters, and of course low quality headphones. HRT claimed that many manufacturers skip out on the Digital Signal Processor in their phones, and have produced the Inline DSP with the aim of keeping digital to analog conversion no longer the bottleneck. I would never categorize myself as an audiophile, but I have to admit that doing their AB test (listening to the same song, back-to-back with and without the DSP made a large difference in the quality of the sound.