The blue whale is generally considered louder than the sperm whale.
While both species produce incredibly loud sounds, the blue whale's calls can reach up to 188 decibels, which is louder than a jet engine taking off. Sperm whales, on the other hand, typically produce sounds in the range of 160-170 decibels.
These calls are used for various purposes, including communication, navigation, and finding food. The blue whale's loud calls are thought to be necessary for communicating over long distances in the vast ocean.
It's important to note that the loudness of whale calls can vary depending on factors such as the individual whale, its age, and the context of the call.