maximum efficiency tapped horns

Hi

just wondering if anyone has any thoughts on designing for maximum efficiency rather than sensitivity.

I have usually designed horns to get a flat sensitivity response and to limit excursion below xmax at all frequencies. I have tried a different approach which is to design the horn to maximise the minimum efficiency within the operating band. I have also been increasing the spec sheet value of Re significantly to account for voice coil heating - as a big voice coil has significant thermal capacity I have assumed Re is approximately doubled at high output. And am not paying as much attention to xmax. designing so that the speaker can reproduce a 50Hz sine wave without exceeding xmax is not what you want it to do in real life.

designing this way you get a higher impedance box that is not so thermally limited mid band (50-70Hz). physically the horn is smaller volume than the max sensitivity model with similar low cut. high efficiency seems to require a larger throat and a horn that doesn't flare until over half way down. also big throat chamber seems to help.

the idea is that once you have a high efficiency box you can choose a much bigger amp without risking voice coil burn-out. higher impedance will reduce the current required from the amp so less heat issues there. in example I have looked at can raise max output at 65Hz by 6dB. sort out any bumps in the response with parametric eq or leave the bumps there if they happen to be in the right place i.e. where the kick is.

It would be really handy if Hornresp could plot efficiency and max output dynamically on the tapped horn wizard screens!

cheers
Phil