Bridging and paralleling are two very different things.
Bridging effects the voltage. Parallel does so with the current. If a design can allow for paralleling you double the current thus doubling the wattage. You also cut the output impedance in half thus increasing your damping factor.
The question of whether or not a set of three basshorns will reach 109dB sensitivity is not as simple as measuring 1watt at 1 meter. Measuring actual sensitivity in the real world is a little more complicated. And the whole 1w/1m standard is very misleading!
1w/1m works adequately for comparing drivers and most simple one to four way dynamic designs. But for planar speakers and line arrays it is basically useless. A typical speaker will measure a particular level at 1m and that level will drop off as a function of distance. A planar or line array will measure one thing at 1m and then INCREASE as a function of distance up to a point. This is because it takes a little space for the entire surface of the planar or all the drivers of a line array to combine.
In the same way, three bass horns are effectively a line array of 6 different 12inch woofers. This takes up nearly eight feet and will only combine at a distance of about 10feet away or more. Therefor, in order to accurately define the actual sensitivity of the entire system you have to measure both the upper frequency horns and the basshorns are the same distant spot. You measure the upper horns to get their true sensitivity at that point and then set the basshorns so that they are of equal SPL at that same spot. THEN you measure the amplifier output. And only THEN do you have a real estimation of the sensitivity of the entire system.
Bridging effects the voltage. Parallel does so with the current. If a design can allow for paralleling you double the current thus doubling the wattage. You also cut the output impedance in half thus increasing your damping factor.
The question of whether or not a set of three basshorns will reach 109dB sensitivity is not as simple as measuring 1watt at 1 meter. Measuring actual sensitivity in the real world is a little more complicated. And the whole 1w/1m standard is very misleading!
1w/1m works adequately for comparing drivers and most simple one to four way dynamic designs. But for planar speakers and line arrays it is basically useless. A typical speaker will measure a particular level at 1m and that level will drop off as a function of distance. A planar or line array will measure one thing at 1m and then INCREASE as a function of distance up to a point. This is because it takes a little space for the entire surface of the planar or all the drivers of a line array to combine.
In the same way, three bass horns are effectively a line array of 6 different 12inch woofers. This takes up nearly eight feet and will only combine at a distance of about 10feet away or more. Therefor, in order to accurately define the actual sensitivity of the entire system you have to measure both the upper frequency horns and the basshorns are the same distant spot. You measure the upper horns to get their true sensitivity at that point and then set the basshorns so that they are of equal SPL at that same spot. THEN you measure the amplifier output. And only THEN do you have a real estimation of the sensitivity of the entire system.