Bests & Worsts Reviews from Amazon

The airflow on the Vornado 184 is not bad when on speed 3 and 4. On speed 1, the fan is barely audible, which is good for night sleeping. But, at speed 3 and 4, there is a low frequency hum that hurts my ears physically. The hum is tolerable for about 10 minutes, but any longer and my ears started to hurt. Some measurement was done on the sound profile of the Vornado 184 using Spec Scope app and Physics Toolbox app on a Pixel 3. For comparison, an old Lasko high velocity was used. The Pixel 3 microphone appears to only be sensitive up to the 24kHz signal. Any data after is consider irrelevent. Test 1 - FFT with Pixel 3 6 inches away from fan The Vornado 184 affected frequencies starts from 100Hz to 24kHz. The biggest shift on the high frequency (2kHz) was a change of ~28dB. For the low frequency biggest shift (150Hz) as a change of ~14dB Test 2 - FFT with Pixel 3 10 feet away from fan The FFT profile is similar to Test 1. This is not surprising, the FFT is for seeing the spectral energy of different frequency, not the loudness. Test 3 - Loudness with the Pixel 3 10 feet away from fan Fan speed 1 - ~47dB Fan speed 2 - ~52dB Fan speed 3 - ~57dB Fan speed 4 - ~62dB Test 3 - Spectrogram with Pixel 3 10 feet away from fan This test give a nice visual representation of how many frequencies are detected, basically a density plot. Fan speed 1 - The densest area is between 0Hz to 1kHz. From 1kHz to 2kHz, the density stars to disperse. From 2kHz to 10kHz, pretty evenly spread out. The density starts to pile up start on 10kHz onward Fan speed 2 - Pretty much the same thing as speed 1 except the densest area last all the way to 2kHz. Fan speed 3 - The densest area now go all the way to 4kHz Fan speed 4 - The biggest change, the densest area goes all the way to 12kHz Look at the attached pics for all the different plots.