
As far as I'm aware, the sample rate setting on the DJM-900NXS2 only affects the conversion that's done on its SPDIF output. If you want to change the rate your operating system converts the USB PCM bitstream to, you have to go into WDM Sound devices or the Pioneer driver panel in your OS, for instance ASIO or CoreAudio. Or since your OS already has the Pioneer USB audio converting to 44.1, you could just change OBS to 44.1.