Review on 🌬️ VIVOSUN 6 Inch 440 CFM Inline Duct Fan with 6"x18" Carbon Filter for Odor Control - Premium Australia Virgin Charcoal Included by Tim Aguilar

Since the reviews on this product are so clearly divided, I decided to try my luck. Unfortunately, my happiness sucks! Although it's not calibrated, my dB meter reads 58 dB at 3 feet from the fan, while the description says 50 dB. This may sound like a minor inconsistency or that it is within an acceptable "tolerance", but it is not. Sound measured in dB is logarithmic (see) and therefore an 8dB increase is actually almost twice as loud (10x louder, but the perceived loudness is about twice as high as I understand sound pressure)! In other words, this fan either feels great right out of the box or is utter rubbish compared to several other similarly priced fans. I will be sticking with the AC Infinity CLOUDLINE S4 for the foreseeable future.