JBL 4367: Inside Photos/Video

[gene_stl]

Having a 110dB efficient driver and then padding it down means you can get away with less compression due to heat in the VC when playing at higher levels, of course this requires the circuit used for padding to be up to the task as well, so you don't simply get heat compression there instead.

This makes zero sense to me. The heat dissipated in the network resistors is totally wasted amplifier energy. If you are multi amping (as you should be when working at the bleeding edge of the state of the art) shelving controls match efficiency NOT power resistors between the amp and the voice coil. The resistor network totally throws away any output stage control of the voice coil. (Please do not refer me to the articles about how damping factor is unimportant, I have read most of them thank you and the use cases cited in them typically do NOT refer to multi amping)
Compression due to voice coil heat is something that is really only a problem in PA use. I guess some young rockers might need to worry about it in their homes especially if they live in the country. But the resistor network does zero to improve that situation. The voice coil temp is proportional to the number of watts fed to the voice coil and the time history of said volume. External networks just waste amplifier power. (Which IS cheep nowadays but still should not be thrown away.)

This make me think that instead of buying these very expensive new JBL systems one should DIY a four way vintage system like this one:

O77, 375 on short horn with slant plate acoustic lens, LE10 and LE15/PR15 in big heavy hand made boxes laminated with Exxon NevaMar.
They sounded great. With a good electronic crossover they could be shelved to perfection.

 

[Scgorg]

Compression due to voice coil heat is something that is really only a problem in PA use. I guess some young rockers might need to worry about it in their homes especially if they live in the country. But the resistor network does zero to improve that situation. The voice coil temp is proportional to the number of watts fed to the voice coil and the time history of said volume.

I don't disagree, for the record, I am merely stating the "why". In addition, both the D2 and 2216ND were specifically made to have extreme output capabilities over time (and consequently power handling), I wouldn't be surprised to see them in PA products in the future, hell, I believe they already use the D2 patent for some of their larger synthesis theater speakers. The negative of using a digital shelving filter (which is what I presume you're talking about when saying "the bleeding edge of state of the art") is that the potential hiss from the electronics can be audible, even for rather good amplifiers. Remember that the M2 is intended for use with crown amps/DSP, which I think would have significant levels of hiss if feeding a 110dB driver. For people who are inclined (and have quiet enough amplifiers) they could certainly rip out the analog filtering in the M2 and simply use fully digital correction/filters.

Again, I don't necessarily agree with JBL on the way they did it (especially not for a supposedly state of the art system), but I don't think it's quite as outlandish and ridiculous as you're making it out to be.

 

[gene_stl]

I don't consider it outlandish and ridiculous, although I wouldn't do it that way.

But in a system priced that highly (even the 4367), I would expect something a little more "purist" rather than something for which excuses need to be made. Efficiency is normally good but perhaps they have too much of a good thing if quality amplifiers need their normal output hiss padded away.
Some power amps are quieter than others and I guess you would need to find some that are very good on that measurement.