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Discussion Starter #1
I redid my sub to a "more sensible" but thought to be less deeply reaching 1.4 cubic foot armrest style box with dual 8 inch subs, though they are "those subs" (code named Sorry Son Of a....) mounted midship of my Dodge Durango (where there was no armrest before) from a premade dual 12 inch Kenwood sub box in the back, which was intended to be removable. Both are sealed boxes. What surprised me is that initially it had near zero drums (read, the deep bass this new enclosure was intended for) but very boomy mid bass with my amp set around half, which is what my rear box meshed well with my door speakers at. However, to get a good mesh out of this new box, I had to tighten the bass filter and turn the amp gain to full, though this sounds almost as good as the 12 inch back box did before. Amp is a Pioneer GM-A5702 btw.

My 8 inch subs call for .54 cubic feet each so I have the volume I believe. Box is well sealed with Gorilla Glue.

Could I just be dealing with phasing since my subs are now in a different place in the accoustical chamber (middle vs one end)?
 

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Could I just be dealing with phasing since my subs are now in a different place in the accoustical chamber (middle vs one end)?
"Gorilla Glued up" meaning that you can get to the wires? Or not?

You could probably devise a test to determine if they are out of phase.
 

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Putting subs anywhere near the middle of the vehicle away from boundaries almost always reduces efficiency below 40-50hz at the listening position. For a bit of fun, climb into the hatch and listen to the system with your head on the floor near the tailgate. There will probably be a noticeable increase in bass.

That being said - don't discount the possibility that something is physically wired out of phase or there's another correctable error in a setting somewhere, etc.
 

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Discussion Starter #4
That's one thing I was figuring, SPL. The subs being within 2 feet of everyone in a full ride and with nothing but soft surfaces around prevents the sub bass from resonating. I have also wondered about phasing. Was shooting for positive push on both, but have wondered if one, whether the front, back, or both should be negative push. They both share the same 1.3 cubic feet so I bet they both should be the same.

...though Holmes, the box itself is sealed with Gorilla Glue, but the drivers themselves are still removeable. I still need to carpet the box as well.
 

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Seem s like disconnecting one of them would yield insight as to whether a single sub is working over the whole band.
 

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Putting a sub in the middle of the cabin won't have great results in terms of output. In the Durango I had the best results with either downfiring in the cargo area or firing back into the cargo door.
 

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Putting subs anywhere near the middle of the vehicle away from boundaries almost always reduces efficiency below 40-50hz at the listening position. For a bit of fun, climb into the hatch and listen to the system with your head on the floor near the tailgate. There will probably be a noticeable increase in bass.

That being said - don't discount the possibility that something is physically wired out of phase or there's another correctable error in a setting somewhere, etc.
This... and also keep in mind that the cone area for 2 8s is 1/2 of the cone area of 2 12s. That by itself is a loss of at least 3dB.
 

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This... and also keep in mind that the cone area for 2 8s is 1/2 of the cone area of 2 12s. That by itself is a loss of at least 3dB.
I knew I would lose a bit of sub bass from using smaller speakers, though my goal for this set is mostly to allow most acoustically based (rock drums and bass) low notes to "come alive" vs my old install, although sacrificing "thump." I plan to create a removable speaker for the lowest lows. However, I did not expect to have to turn the gain control close to 60 degrees or more up to reacquire my match in volume. (Although I haven't had a chance to try to properly diagnose or calibrate it.)
 

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Discussion Starter #9
Update: in the process of switching to another amp, I found I made a wiring screw up (swapped one of the phases, so one pushed on positive but the other pulled.) Sounds much better now.

Also used white noise to more appropriately tune it. Response looks relatively flat from 100Hz to on up into the high kilohertz, which is what I was after. With some songs, it sounded quite good.
 
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