I recently upgraded to a new head unit in the car, and it's the first I've owned that offered 12 and 24 db slopes on both high and low pass filters (has to be one or the other if either filter is on)
All speakers are externally amplified between 3 amplifiers, 1 of which is for subs which I won't discuss. I have tweeters and two 8" woofers on one amp (Crossfire VR302) and six 6.5" on other amp (Crossfire VR402).
Before adding the 8" woofers (NOT subs), I ran both Crossfire amps with full-range settings and head unit set at 100hz high pass cut with 24db slope as four of the 6.5" are only rated to 100hz and above and they actually mean it.
The 8" woofers are rated 35hz to 3khz and are in separate ported boxes, and the 100hz cut is too high for them.
Crossfire states the HP/LP x-over uses a 12db slope.
Got enough back-story?
If I set the VR402's x-over to 100hz HP for the 6.5" family of 6, it's going to add a 12 db slope from the amp. And I'd probably have 50hz or 63hz as new HU high-pass so the 8" woofers cover more vocal and instrumental ranges, but I'm forced to run a 12 or 24db slope at the HU if I keep the high-pass on
1. That's not going to work, right? Won't the HU's 50hz 12/24db slope interfere with the amp's 100hz 12db slope?
2. Is the only option to disable the HU high-pass and set both amplifier's high-pass cuts and just accept the 12db slopes both amps offers?
3. Also, what happens if HU and amp are both set at same freq. cut and BOTH are adding a 12db slope? Would it be cumulative?
All speakers are externally amplified between 3 amplifiers, 1 of which is for subs which I won't discuss. I have tweeters and two 8" woofers on one amp (Crossfire VR302) and six 6.5" on other amp (Crossfire VR402).
Before adding the 8" woofers (NOT subs), I ran both Crossfire amps with full-range settings and head unit set at 100hz high pass cut with 24db slope as four of the 6.5" are only rated to 100hz and above and they actually mean it.
The 8" woofers are rated 35hz to 3khz and are in separate ported boxes, and the 100hz cut is too high for them.
Crossfire states the HP/LP x-over uses a 12db slope.
Got enough back-story?
If I set the VR402's x-over to 100hz HP for the 6.5" family of 6, it's going to add a 12 db slope from the amp. And I'd probably have 50hz or 63hz as new HU high-pass so the 8" woofers cover more vocal and instrumental ranges, but I'm forced to run a 12 or 24db slope at the HU if I keep the high-pass on

1. That's not going to work, right? Won't the HU's 50hz 12/24db slope interfere with the amp's 100hz 12db slope?
2. Is the only option to disable the HU high-pass and set both amplifier's high-pass cuts and just accept the 12db slopes both amps offers?
3. Also, what happens if HU and amp are both set at same freq. cut and BOTH are adding a 12db slope? Would it be cumulative?