Data was taken by using the SoundDevices USBPre line level rca input from the Alpine CDA-9887 output directly. Levels are relative. Autosound 2000 Track 18 (un-correlated pink noise) was used as the source.
I am using the Alpine DRE-A200 as a crossover between my tweets and mids off the Front outputs on the 9887. you can see the 12dB/oct slope of that crossover.
There is the same consistent drop at the crossover frequency (6 and 12 are the same, 18 and 24 are the same at the xover point). Certainly, when choosing crossover slopes and points, the drop at the crossover point should be taken into consideration - resulting in some overlap with the crossover points.
4kHz crossover point, slope varies 6 to 24dB/oct. Front output of 9887
1kHz crossover point, slope varies 6 to 24dB/oct. Front output of 9887
200Hz crossover point, slope varies 6 to 24dB/oct. Rear output of 9887
50Hz HPF, 250Hz LPF, slope varies from Full to 6, 12, 18 & 24dB/oct. Rear output of 9887
Then i played with the mic for a bit. Played with crossover settings. I had the laptop in the passenger seat, mic at my head (moving around to average out peaks/valleys). This is the front stage only (no sub). Crossover points are:
Midbass: no HPF (Full), 315Hz LPF 18dB/oct
Mid: 250Hz HPF 18dB/oct, 3.5kHz LPF 12dB/oct
Tweet: 3.5kHz HPF 12dB/oct
One line is measured 1/24th oct, the other line is a smoothed version of that line.
naturally, with the subs the low end is (much) higher, but I wasn't running the sub during the RTA testing today and was more interested in midbass response.
here are individual graphs of crossover slopes. This is what i've been listening to, set by ear. It is close to what I expected, though i'm more then 3dB down at the xover points.