A recent study  used a SoundEar3-300 noise warning sign as an isolated intervention to determine whether visualizing noise could produce a sustained noise reduction in adult critical care. It proved a significant noise reduction of 3.9 dB (from 57.4 dB) in median ambient sound levels and saw a significant reduction in peak sound levels (0.7 dB reduction from 66.0 dB). After 4 months with continued use of the SoundEar3-300, researchers found a sustained noise reduction of 3.6 dB compared to baseline recording before introducing the SoundEar. The device acted as an isolated intervention to significantly reduce night-time ambient and peak sound levels, a change that was sustained after a four-month period.
In another study from 2014 , a SoundEar device was used as a part of a noise reducing initiative at an operating theatre in Hannover, Germany. This study showed a significant reduction in noise levels in the operating theatre from 63 dB to 59 dB. Moreover, the noise reduction led to a significant reduction in the number of complications after surgery and reduced surgeons’ stress levels by 20%.
2. https://www.pubfacts.com/detail/24394594/A-noise-reduction-program-in-a-pediatric-operation-theatre-is-associated-with-surgeons-benefits-and- www.soundear.com