The on-board radio is usually enough. An adapter is worth it where the access point is far enough away that the built-in antenna struggles.
Which adapter
We suggest the official Raspberry Pi USB Wi-Fi dongle where you can find one, which is not always.
The adapter we have tested and confirmed is the Panda Wireless PAU06.
Configure it
An adapter is a second wireless interface, so the network configuration has to name it.
- Generate a
network.yamlwith the Network Config Generator, or open the one you already use. - Replace
wlan0withwlan1. - Copy the file to a FAT32 USB stick and insert it into the player.
The player picks up the configuration and reboots. See Connect to Wi-Fi for the full USB drive process.
Note
This applies to the Raspberry Pi based standard player. A Player Max has its own radio and does not take an adapter.