The reported brightness levels in the above table were with the projector's zoom lens set to it mid-position, with the lamp set to Normal Mode (the brightest mode), and the factory default settings for each picture mode, which included Brilliant Color being turned on. As noted above, the Color Lumens for this projector is much lower for each of the picture modes, as is typical for many single-chip DLP projectors of this class.
Operating the projector in Eco mode reduced the lumens output by 20%.
I found that lumens output varied very little over the limited 1.2X zoom range of the MX631ST. Brightness uniformity did vary across the projected image with the left side of the image showing very little drop in brightness as compared to the center of the image, but the brightness fell off on the right side of the image, measuring a worst case 40% drop at the bottom right corner. This was with the projector table mounted and with no digital keystone correction being used.
I checked the native on/off Contrast Ratio and measured a maximum of near 2,000:1 in the best case, which is certainly better than 3LCD projectors of this class and is competitive with other DLP projectors in the class.
BenQ did not provide compatible 3D glass and the performance of the projector's 3D mode was not tested.
[sam_pro id=1_84 codes="true"]
The MX631ST has a single 10 watt speaker that is capable of producing reasonably good sound quality. Certainly adequate for use in most conference rooms or small to perhaps moderate size classrooms. if you really need higher fidelity or higher volume levels use of an external power speaker(s) is suggested. Overall, I would rate the overall audio performance a little above average for this class of projector and certainly much better than can be found with smaller pico and pocket projectors.