i've just had the most awesome evening's hornresping, i spent a lot of the time looking at the predicted diaphragm displacement too and i have had to re-evaluate some of my driver applications. the dual sn12b horn of about 80cm length that i had been playing with will absolutely rinse the driver at rms power levels, a pity as the response was looking nice.
the plot for the b&c 12ndl76 is pretty much the same shape at first glance, but wind up the power to the cab's rms rating of 800 watts and the drivers remain nicely within manufacturer's given x-max, even below crossover point and the plot starts to look very, very loud. with two boxes the graph is smoothing out nicely, and the proposed cabinet volume has room for the combined system volumes of the dual 12" horn, an x-tro sized high mid horn, 1" horn, drivers and wood, give or take a bit.
here's the data...
it isn't much worse on an 80 cm horn but i'm really clawing for bottom end extension. in spite of this i wouldn't want to cross this over too low as the plot starts to roll off just below 100 Hz.
if i can get that horn to fold into that shape without doing anything too contorted,
if the resulting layout is replicable by human kind and then finally
if the ensuing cabinet doesn't sound
diabolical! then i reckon it would be a good performance from a large but manageable size.
james.