95Honda

It is a complete waste of time to set your gains like this. You can't fully control voltage drive upstream, especially if someone else is controlling the source material, therefore it is pointless to do this.

Morel used to make a lot of shallow design subwoofers, back before they were known as shallow designs. They just used bigger voicecoils with internal magnets and really cheaply made stamped steel baskets that made the design shallow enough to fit anywhere. I installed a few in the early 90s. I have done a lot of installs with 8s, I just finished another dual 8" setup for a 1-ton Dodge last week. Displacement is displacement. There is nothing magical with motor force. If it is a small cone it has to move a lot to get loud. This 8 looks like it will move a lot...

Hmm, I wonder if one of those would be enough? Do you have the T/S?

Picked up a new F250 Crew Cab for the wife and want to fix the substage of the factory system. Looking for a class-D that has speaker level inputs and auto turn-on. Looking for a pair of 6 1/2" or 8" subs to go behind the rear seat. If anyone has anything they would like to get rid of, let me know! Looking for stuff in good or better condition only... Thanks!

Adding anything passive inline with the drivers when using active filters defeats the whole purpose. This practice has spawned from wives-tales in the late 80's when active was first being used in car audio and people didn't understand it...

How did you pick your volumes and tuning? If you didn't model, you need to go back and do that first. That is the only objective way to predict how it will "work"...

I don't see how you could go wrong with 4 10s vented and tuned around 30Hz for just about all music...

What do you think "loading issues" are? Unless the vent is too small, and the box Q drastically changes to the point of a leaky sealed (or Aperiodic) box, the drivers will behave the same regarless of vent location, baring extreme variations in box dimensions. If you were really concerned about Hemholtz resonance behavior, I would get rid of the aggressive curve or kerf on one side as this has an unpredicable effect on vent performance. I think we get tied up in heresay too much in car audio, and not hard science.

If you added a spider, raise the Fs and drop the Vas a little if you model... Like 5%-10%... 40in3 isn't a small amount of cross-sectional vent area, for any 15" driver with almost any power input... It is actually a lot...

Looks good. I would Line-X it, stain just will never look great once you bung up some of the veneer... Here is a single 15 I Line-X'd...

It is more about overall driver Q. Lower Q drivers need more augmentation because they self dampen, that is why vented works better for them... Higher Q drivers need less augmentation due to the fact that they are under-dampened... Sealed and 4th order band-pass lend well to this. Also, a 6th order vented bandpass has a lot of variables to screw up...

Model both designs and post plots on here and we can help you decide what will better suite your needs...

SSF is a high pass filter and like said ^^ is set according to your enclosure resonance. For your lpf question, the answer is an unequivocal "NO"...

3" more inductance? Than what?