Our smartphones have become our default source of music. The only problem here is they are very convenient for music listening, but smartphones aren't made to sound great.
A digital-to-analogue converter or DAC chip converts digital music files to an analogue signal output from your phone. All phones, laptops, and really any device with a 3.5mm output would have an inbuilt DAC. Unfortunately, most smartphone DACs are woefully inadequate in giving you a good-quality sound output.
A dedicated portable DAC is a powerful device that connects to your smartphone through Bluetooth, USB-C, or Lightning cable and bypasses the phone's built-in DAC. The DAC can decode high-resolution audio up to the highest formats and can have a profound effect on the sound, making your listening experience on your headphones more engaging.