This is my first post here, so I hope I don't tread on any toes. I used to be the Hybrid Audio UK distributor and am currently the competition team captain, so I have a reasonable level of experience of L3s, L3v2 and L3SE.
I saw some posts about available speaker diameter and I'm not sure what constraints the car has. The L3 family are all 3.7", and there are likely to be more significant factors for choosing between a 3.7 and a 4" driver than diameter alone. If it's more like 4.5" hole, then things get a little more clear cut. The L4 and L4SE are 4.65" diameter, so they might be an option with a little work?
With regard to the 60 degree off-axis comment, it should be noted that drivers with phase plugs act as if they were half the diameter at higher frequencies - what this means is that beaming doesn't occur until a much higher frequency.
So whilst the original L3 (sans phase plug) would struggle to reach much above 5KHz at 60 degrees off axis, both the replacement L3v2 and the L3SE can play cleanly to 10KHz at 60 degrees off-axis. There is no problem at all in this configuration and there wouldn't need to be any significant processing at all, except to compensate for environment/any install-related issues.
As for the specific application in this instance, unfortunately I'm not particularly familiar with the cars in question, so can't really give any platform-specific advice. What I can do is say that in my experience, higher crossover points for mids are preferable to lower ones. Our ears are most sensitive to 500Hz through to 3-4KHz (the range of the human voice, and general "danger" or "food" sounds - what they've evolved to hear). Crossovers in this range are likely to be much more audible than crossovers above or below. Any slight mismatch in phase and you'll hear the crossovers.
HAT's first speaker was the L3 and it was designed to play this high even at 60 degrees off-axis (I suspect even the diameter comes down to the maximum diameter mid that can be crossed over at at least 5KHz), specifically so that users can have a "point source" driver. The entire range was then designed to fit in with this principle, and it's one that's served competitors well all over the world.
It's not the only way to go, but it can definitely work.
Even the L6/L6v2 with their phase plugs are capable of playing to 5KHz at 60 degrees off-axis - same reason
Having heard the difference, I wouldn't want to cross over any midrange in the lower frequency ranges anymore. Unfortunately many manufacturers need a low mid to tweeter crossover in their 2-way systems because they choose cone materials/surrounds which exhibit harsher breakup modes than the HAT paper cones do, so they simply sound awful played higher - and then they share the speakers and/or crossover components on their 3-way systems, so even then they sometimes don't get around it. As a consequence, a low-playing tweeter is required, and the crossover moves in to the worst range for it.
I didn't intend to get this technical, but I love car audio, specifically in-car, and love to see people make informed decisions. If anyone has any HAT specific questions at any point, please feel free to message me. As I say, I'm not longer distributor/dealer, so there's no financial motivation.
Last edited by mulletboy2; 02-04-2013 at 06:47 PM.