Like Tubegroover I don't want to rain on anyone's parade, but I thought I would point out what appear to be highly credible
measurements of the Reference 3A MM de Capo BE, performed by the National Research Council of Canada. They indicate a measured sensitivity of 86.7 db/2.83 volts/1 meter. As can be seen in the first graph, the sensitivity is in the vicinity of 92 db at a few specific frequencies, but is considerably lower at a great majority of frequencies.
Also, the impedance curve shown near the bottom of that page indicates that their impedance is about 6 ohms throughout much of the mid-bass region, where lots of energy is often required. 2.83 volts into 6 ohms is 1.33 watts, which is 1.2 db greater than 1 watt. So on a per watt basis, the 86.7 db figure is arguably optimistic by 1.2 db, meaning that 85.5 db/1 watt/1 meter is probably all that can be counted on with a lot of music.
Something to consider, despite the comments by the esteemed designers mentioned above. Regards,
-- Al