The Acer K138ST is exceptionally quiet as compared to the AAXA M5 and AAXA M6 I reviewed. Those claimed to have the same level of fan noise, but they are definitely much louder. The K138ST's fan runs at 33db at full power - that's just about the same as my Epson HC5040UB, which I can only hear if the volume is turned really, really low. The Acer K138ST is a short throw, as mentioned multiple times, which means that it will be positioned in front of your seating area and you are more likely to hear the fan than if it were on a high rear shelf.
That it is 33db at full power is a real plus, as that's truly excellent for a home entertainment projector, especially in the pocket projector class. In ECO Mode, the projector's fan is rated at 29db - even better. If you use that Bluetooth speaker function, you'll hear the fan even less because you'll have the ability to turn up the volume enough to drown out anything you might still hear.
Up next is our Summary Page, where I - you guessed it - summarize this review and wrap a neat little bow around our discussion of the Acer K138ST. I will also discuss the Acer's direct competition, the AAXA M6, which will go head to head in the upcoming Pocket Projector Comparison Report (2018). Now, onto the final page of this review!