I haven't seen a coax without a built in crossover, unless you are talking about those little "whizzer" cone speakers. I tried to make it clear that I meant an apples to apples comparison, sorry for any confusion.
On the coax vs separate topic, look at it from a positioning point of view alone and you'll see my point. Completely factor out any passive crossovers and assume the speakers are naturally rolling off out of their frequency ranges for a moment.
The term coaxial, broken down being "co", as in together, and "axial", as in an axis, refers to in our case two drivers whose output are on an identical axis. Obviously, the dispersion patterns of frequencies and drivers vary, due to wavelength, cone shape, the presence of "phase plugs" and so on, but the speakers are on top of each other and radiate energy along the same imaginary line. Therefore their output is almost identical in regards to its origination point in time, and the output of both drivers is identical in its physical location. This all equates to less phase problems, since the farther the distance from drivers, the higher probability that phase problems will arise to harm the systems imaging, and better point-source imaging, since adjacent output bands (as in mid and high freqs) are eminating from the same location.
Take a separate set now. Salespeople like to make various claims about them constantly "hitting harder since there ain't no tweeter in the woofers way", "imaging better since the tweeter can get stuck higher in the door or dash" and so on. As far as the louder midbass and midrange go, is that logical to think that the tiny tweeter is going to block that much of the larger drivers output? Not at all! When imaging heigth comes up, ask the salesman why humans have ears on the sides of their heads rather than the ?top and bottom. He'll have no idea what the hell you mean, but humans can easily localize the origin of left versus right, but not up versus down, thus shooting the "higher tweeter, higher stage" theory down totally. We know to look up when we hear a jet engine out of habit, since we associate that sound from our childhood with a flying machine, but not because we can tell the sound is above us, especially when you factor in reflected waves. Moving the drivers farther apart will also be likely to cause the abovementioned phase problems, which will smear your image across the soundstage. Why buy excellent speakers just to have them perform less than adequately? The install would be more on the components as well, which is yet another reason dealers love them.
Yes, separates in the hands of an installer who knows what to do with them can sound incredible. No, not every separated mid/tweeter has phase problems, and if they do the owner or installer may possibly understand this, have equipment to measure it, and compensate for it with processing. Ever noticed that the vast majority of winning competition cars put a mid and tweeter in the kick panels? This is to attempt to make the left and right side more equidistant to the driver's ears to aid in imaging. Notice how closely the mid and tweeter are in these cars? They are either as close as possible, or sometimes the tweeter is suspended above the mid, simulating a coaxial mount.
If you really absolutely have to have the Type X's, there are some on Ebay for insanely cheap prices:
Type X auction
I honestly would tell you, if I were your installer, to spend your extra cash saved by buying the Type R's instead of the Type X's on having the doors made a more suitable enclosure for the mids. Using a damping material, like the well known Dynamat to help seal the doors will truly make a daylight and dark difference in the midbass area, especially. Check out a thread started by Sreidvt on this forum regarding the topic. He photo'd his work and put on up on his site, and I'll say that he did a job that any really good installer would be jealous of, so it is a good DIY project you may want to tackle before the install takes place.
A good 1/3 octave EQ. It would make more difference in the system than the speakers could ever accomplish. The X 6.5" set is $450.00, the R 6.5" set is $280 and coax is $200. That is a $170 to $250 savings depending on whether you went with the comps or coax, nearly offsetting the price of the EQ. ?A shop with at least an RTA (real time analyzer), can "see" the sonic dips and peaks and tune them out, or at least help the problems, and get a smooth, ear-friendly response from the system.
