According to Ibai(based on official data by Riot Crower), the EU LCS Finals in Madrid were the loudest in the history of the EU LCS, reaching more than 110 dB, which is comparable to the noise a plane does when it takes off. And one more thing, this was measured during the opening ceremony of the finals.
Source(tweet in Spanish): https://twitter.com/LVPibai/status/1039244766746222592
