Regarding the noise issue of your Bluetooth speaker when the media content is transmitted to the projector via HDMI cable, we would like to share some findings with you. The static noise may occur in some scenarios, including the interface is being changed (e.g., the audio signal of the source input transmitted from HDMI input is changed to Bluetooth speaker output), or some metal objects or batteries are placed nearby the Bluetooth speaker. As the static noise would be most noticeable when the volume of the speaker is set at high levels, we suggest you try the following steps to improve the symptom:
1. Lower the volume level of the Bluetooth speaker.
2. Use the built-in speaker of the projector to get rid of the static noise.
If you have any questions, please contact your local BenQ support team for further assistance.