Connecting an external sound card to your phone
In addition to standard CD quality (44.1kHz), the music playback program supports higher sampling rates of 88.2kHz, 96kHz, 176.4kHz, or 192kHz. However, these higher frequencies are not supported by the built-in sound card on iPhone or iPad.
It is possible for you to take advantage of these frequencies and thus enjoy even better sound quality by connecting an external sound card that supports iOS and these frequencies to your iPhone or iPad.
To connect an iOS compatible sound card, you need one of the following camera adapters:
Lightning to USB 3 Camera Adapter. NOTE! This adapter can simultaneously charge your phone.
In some cases, in addition to the camera adapter, you may need a USB Hub with an external power supply to get the sound card working. It is needed if the sound card is powered by a USB port and needs more power than the iPhone can supply for it.