From the crutchfield website
- Files up to 16-bit/48kHz are streamed without compression or transcoding. High resolution audio files (24-bit/192kHz), are down-sampled to 16-bit/48kHz for transmission. This allows for the most reliable streaming experience over WiFi to multiple speakers.
- For those who wish to hear high resolution audio as originally intended, Critical Listening mode in the DTS Play-Fi app will enable native rendering of high resolution files up to 24-bit/96kHz, without down-sampling or network synchronization adjustment.
I find the easiest way to to get hi res streaming is an IPad, camera kit, and a USB upsampling DAC like you see used for headphones.