steve_1979 said:
There's a graph for the DM10 bass driver (with no crossover or tweeter) on the AVI website.
http://www.avihifi.com/dm10-driver-measurements.html
Note that the response is smooth right up to 4kHz which is really exceptional performance for a 6.5" driver. The DM10 crossover at 2kHz is very steep so you never get to hear the cone break up like you do with other 6.5" drivers. This is what makes the DM10s different to all other 6.5" speakers and it's this along with a few other things which allows them sound so smooth and clear.
The SB drivers are good value with good motors but there is nothing unique about them. The reason crossover slopes as high as 8th order are not conventionally used between 6.5" and 1" drivers on a flat baffle is because it makes the steep change in directivity with a 4th order slope even worse. Most of the energy waggling our ear drums when listening at home in a room comes from reflected sound and so the almost step change in the frequency response of the reflected sound at 2kHz significantly colours the perceived sound by emphasizing the higher frequencies. Perhaps this sounds good as a sound effect but it is not high fidelity.
If we want high fidelity then we need to avoid sharp changes in directivity and to minimise the resonant regions within the driver's passband. This is straightforward to achieve by using a smaller midrange driver and a larger woofer driver instead of a single midwoofer driver. Waveguides can also help shape the directivity of the smaller driver to match that of the larger driver.