Confidence 5 sensitivity

The official website says 83 dB but some forums say 86 dB.

In short: the sensitivity is 83 dB 

In 1997, a slight change was made to the woofer, resulting in a 2db increase in output below approximately 80Hz. This change was made during production and there was no official announcement of a MK II version based on this modification. However, all serial numbers after 839508 include the new driver. Although the overall sensitivity did not change significantly, the most accurate measurement is likely around 83db. It's important to note that these speakers require a substantial amount of power.