i have a Grand Cherokee with three amps with four .5 farad caps and two dual 10 sub boxes.
I decided i wanted my seats to be able to be upright and built a two level area in back...
the 2500d, RF301x and JVC 4750 along with two distribution blocks and four .5 farad caps are on the bottom level and 8" above is a 3/4 mdf shelf which hold both sub boxes.
My questions is: Will the roughly 32" X 8" X 40" amp rack space affect bass? This space is fairly open and padded on bottom.
Although it is said that bass frequencies are omni-directional sound waves;
There are different output levels you can get just by changing the location of your subwoofers, as well as hot spots and cold spots.
Test it for yourself. Take a home subwoofer and put it in one of the corners of your living room. Now crank that sucker up with heart stopping bass. Have a seat in the middle of the room and listen to it. Listen to the lowest note you can hear from that location. Listen to how loud it is.
Now go to the opposite corner of the room and listen to the bass. You will notice a considerable amount of gain in volume as well as lower frequency.
Next, move the sub about 3 feet from the wall (in the center of the wall) and suspend it about 2 feet off the floor.
Now listen to the sub from both previously mentioned locations. Although, at first you will see considerable reduction in volume and low frequency cutoff; you will notice that the sound quality has improved tremendously.
Location of any speaker, direction, and elevation has a lot to do with sound quality and resonance.
In my opinion, your scenario will produce cleaner bass; however it will not be as loud as if they were located in the deepest, farthest corner of the vehicle.
Last but not least; crank your car system up, and listen to it while you are inside the car. Now step outside 7-15 feet away, and leave just the driver door open. You will notice an increase in volume, as well as a lower frequency cutoff. The quality of the sound will be reduced but the volume is gained. This is because your vehicles interior volume is acting as a secondary resonance enclosure for your subs (free unexpected amplification).
In my opinion, your setup is in a good location, and elevation.