1 pointI'd echo SME here. The Othorn is still a very good sounding design but I'd consider the Skram instead. It's smaller, lighter, has flexible tuning options and is simpler to build. Output and SQ should be the same if not a bit better due to the more extended top end. Issues don't start till higher in frequency that the Othorn.
1 pointI have been reading these papers by Kipple: http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Green Speaker Design Part 1.pdf http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Green Speaker Design Part 2.pdf In the second paper they improve the efficiency of an overhung driver by reducing the coil height to the top plate thickness and then compensate for the resulting non linear behavior. The benefit of this in their example is a 39% in voice coil temperature for a given output compared to an overhung driver (~3dB output gain in the non excursion limited region for the same driver). Considering the IPAL driver already is designed to be a transducer with dedicated amplifier and it has a huge coil overhang it would seem that with just shortening the coil a bit and a new version of the IPAL mod that implements the kipple DSP work they could increase the efficiency/output substantially (IPAL2?). There would also seem to be benefits form changing reducing kms but I understand that this is required to have small clearances in the voice coil gap due to rocking modes.
1 pointHello also from Denver here! You started in on one of the Othorns already? I'm not sure how far along you are, but you may want to consider the Skhorn or Skram instead. They have much cleaner response to well above 100 Hz, and I think most people here regard those two designs to largely obsolete the Othorn. If you have a choice, I very strongly suggest you go with one of these newer BP6 designs. If you already have Othorns you want to use, then I'd say the situation is a bit of a mixed bag. The 80-100 Hz region is pretty narrow---essentially 4 semitones (or a major 3rd) apart. However, crossovers are not an all-or-nothing thing but involve blending over a pretty wide range, even with e.g. 4th order slopes. IMO, the Othorns will probably sound even better crossed even lower at like 60 Hz, at which point, a dedicated mid-bass section (for say 60-150 Hz) starts to make more sense. Looking at Ricci's compression sweeps for the Othorn, I don't expect EQ applied above 100 Hz will be very help helpful because the response above 100 Hz actually changes a lot with the signal level at medium-to-high levels. EQ which sounds good at low signal levels might actually make things worse at high signal levels.