I don't know about those libraries personally, but it is possibly up to you to flip the chip select pins before sending/receiving data. If you don't define the CS pin in begin(), or the equivalent call, you will likely be expected to make the device active any time you call a class member function dealing with that device.
The docs should tell you for sure, although (unfortunately) I find a lot of documentation is more of a how-to, with very little info to guide you along if you step outside the example configuration.