Off Axis Midbass

What point are you going to cross them over at?  Unfortunately they aren't out yet, but I recomend Resonant Engineering's XXX 6's.  It does have a large mounting depth at 3 3/4".  But they have 12mm of one way linear throw.   Also, they use our XBL^2 motor so you should really like the way they sound.  In fact, if you position them correctly, they should be able to take over the midrange duties as well.  That means you won't need the 4's.  Here's a link to their site: http://www.reaudio.com/flash_index.html

BTW, Dr. Kippel himself measured one of these drivers at CES.  I've seen the Kippel report for this driver, and it is most impressive.  The BL distortion is actually lower than the Cms distortion over most of the bandwidth.  This is HIGHLY unusual to find in speakers.  In fact, Dr. Kippel was so impressed that he offered to test any of our drivers in the future for free. 

Steven Kephart

Adire Audio

Unfortunately I don't have that information.  I would expect fairly soon though.

You could still get away with using the mids and tweets.  The tweets should provide the stage height.  And since you are using the kicks, that will maximize the pathlength differences (which is important below 1000 Hz), which will even further improve your soundstage.  What I do recomend though is a VERY steep crossover slope on the seperated drivers.  That will reduce Lobing as much as you possible.  You will still have lobing issues either way, it's just if you use the 4's, lobing will happen at a much lower frequency.  I just believe it will be better to not use the 4's as you can match the mids and tweets up, and use their natural rolloff to aid in a steeper slope.

Steven Kephart

Adire Audio

Hehe, I know exactly what you mean.  My car has been a "project" for 3 years now I think.

Please feel free to ask what you don't understand.  I will do my best to help.  My guess is that you might not know what lobing is?  I will do my best to describe that.

Let's say you have two speakers producing the same frequencies.  It isn't a problem really as long as you have them close together.  The distance is determined by the wavelength of the highest shared frequency.  Now this doesn't eliminate the problem I'm describing, but it does minimize it.  As you probably know, ideally you want a single source providing the full frequency response.  What happens is that the farther you put the speakers apart, the more the frequency they produce is out of phase with the other.  This means that you get dips in the response.  And to make it even worse, the dips increase as you get further off axis.  This is what is called lobing.  Since in a vehicle you are sitting at different axises of the left and right speakers, one may have more of a dip than the other.  This makes it very difficult to fix the problem with processing.

Now with components, you only have this problem at the crossover frequency.  This is because as the tweeter and midrange roll off, they still produce similar frequencies, but at a lower level.  So lobing is still an issue, and is the reason why most people recomend keeping the tweeter and mid close together.  And obviously the lower the crossover frequency, the farther apart you can put them.  This is because the wavelength of that frequency is longer.  Also, now you can see why I recomended a really steep crossover frequency.  Because the less the tweeter and mids frequencies overlap, the less lobing you will have.

Steven Kephart

Adire Audio

Do you mean 36 dB per octave? 

I totally forgot, but those mids I mentioned are listed on our website.  We are releasing them in an 8 ohm version, but at lease we show specs for it, and give a price of what WE are selling it for.  That should give you an estimate.  It is the Extremis 6 found here: http://www.adireaudio.com/StockProducts/raw_drivers.htm

Steven Kephart

Adire Audio