If you are building or modding a CX31993 board, inspect the decoupling capacitors. The datasheet recommends placing 0.1µF and 10µF ceramic capacitors as close to the VDD pins as possible to filter high-frequency noise. Adding an external ferrite bead to the USB VBUS line drastically cuts down computer switching noise.

Crucially drops as impedance rises (typically 1Vrms to 2Vrms).

The datasheet requires an external 32.768 kHz crystal but doesn’t specify load capacitance clearly.

USB 2.0 High-Speed with integrated UAC 2.0 (USB Audio Class 2) compliance. Decoding the CX31993 Datasheet Ambiguities

Users frequently report a handful of persistent issues with CX31993 dongles. Here is how to address and fix them: 1. The High-Frequency Noise / Hiss