Excellent detective work, Schubertmaniac.
Yup, Magnepan plays the numbers game a bit in quoting 86 dB for a 2.83 volt input. You see, 2.83 volts into 4 ohms is 2 watts, not 1 watt.
One additional factor is compression. I don't have access to dynamic compression measurements on Maggies, but let's assume they compress about as much as the average 83-dB effienct movng-coil speaker (all moving coil speakers are subject to thermal compression, and in general the lower the efficiency the worse the compression). Suppose we have a 200-watt peak musical impulse, which we would expect to give us 106 dB from our 83-db/1 watt efficient Maggies. But taking compression into account, I would estimate that 200-watt peak input to give us about 101 dB output, and possibly less.
Note that electrostats also suffer from dynamic compression, but it's mainly determined by the transformer's internal properties and has a less direct correlation to overall electro-acoustic efficiency.
Schubert, the power requirements for the Maggies doesn't follow conventional point-source theory as you increase the listening distance. Maggies approximate line sources, and benefit from the significantly more gradual fall-off with increasing distance.
Theoretically, in anechoic space, sound pressure level falls off by 6 dB with each doubling of distance from a point source, but only 3 dB with each doubling of distance from a line source.
I took some measurements in my room to get a handle on the real-world implications of line source vs point source radiation. I measured a conventional point source speaker and a line source speaker at 1 meter and then at 8 meters (the practical limit of my room), using pink noise. The point source speaker's output fell off by 11 dB going from 1 meter back to 8 meters, but the line source speaker's output only fell off by 4 dB!
In my mind, this is one of the things Maggies do very well - you see, the kind of sound field set up by a line source speaker more closely approximates the sound field you encounter at normal listening distances at a live performance. I think this is one reason the Maggies generate such a lifelike "feel" (along with their utter lack of distracting boxiness).
Yup, Magnepan plays the numbers game a bit in quoting 86 dB for a 2.83 volt input. You see, 2.83 volts into 4 ohms is 2 watts, not 1 watt.
One additional factor is compression. I don't have access to dynamic compression measurements on Maggies, but let's assume they compress about as much as the average 83-dB effienct movng-coil speaker (all moving coil speakers are subject to thermal compression, and in general the lower the efficiency the worse the compression). Suppose we have a 200-watt peak musical impulse, which we would expect to give us 106 dB from our 83-db/1 watt efficient Maggies. But taking compression into account, I would estimate that 200-watt peak input to give us about 101 dB output, and possibly less.
Note that electrostats also suffer from dynamic compression, but it's mainly determined by the transformer's internal properties and has a less direct correlation to overall electro-acoustic efficiency.
Schubert, the power requirements for the Maggies doesn't follow conventional point-source theory as you increase the listening distance. Maggies approximate line sources, and benefit from the significantly more gradual fall-off with increasing distance.
Theoretically, in anechoic space, sound pressure level falls off by 6 dB with each doubling of distance from a point source, but only 3 dB with each doubling of distance from a line source.
I took some measurements in my room to get a handle on the real-world implications of line source vs point source radiation. I measured a conventional point source speaker and a line source speaker at 1 meter and then at 8 meters (the practical limit of my room), using pink noise. The point source speaker's output fell off by 11 dB going from 1 meter back to 8 meters, but the line source speaker's output only fell off by 4 dB!
In my mind, this is one of the things Maggies do very well - you see, the kind of sound field set up by a line source speaker more closely approximates the sound field you encounter at normal listening distances at a live performance. I think this is one reason the Maggies generate such a lifelike "feel" (along with their utter lack of distracting boxiness).