Hi vanra,
does your BT speaker really accept simple WAVE files? Really? Do you have a manual for that speaker, describing the software interface?
the bluetooth 'write' vi can only send strings
A string is just a 1D array of U8 (aka "bytes") and there are functions to convert between array of U8 and string. Once your data is available as an array of U8 you can easily transfer it using this function!
FlattenToString is a similar tool, but it may contain additional data as is described in the LabVIEW help…
Best regards,
GerdW
using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019