I already have OBS, can I use Rumble Studio and OBS together?

Yes, it's possible to use OBS in conjunction with Rumble Studio. Users typically do this in order to leverage Rumble Studio's unique features: inviting guests, live chat integrations, and more, while maintaining their existing OBS setup. In order to send video from OBS to Rumble Studio, you need to activate the virtual webcam in OBS. You should then select the virtual webcam as the video input in Studio. In order to send audio from OBS to Rumble Studio, you need to send audio from OBS to a virtual loopback cable. You should then select the virtual loopback cable as the audio input in Studio. There are several loopback cable alternatives, such as this and this.