Hello Raghu. When projecting on a wall, different variables can affect image quality, such as ambient lighting, paint color, texture, and surface finish. We recommend using the SilverFlex Ultra Ambient Light Rejecting Mega Screen to produce the best results. You can use a Roku device, but please note Android TV is already included, and within the interface, you can connect a Bluetooth speaker. Regards, Kevin - The Epson Team.