Ok I have last years model FI Q 15, and I have the new model and they both have the same options, P chamber, extra spider. They are in a shared chamber box, 8.2 cubes at 33hz. The new one with the black basket has had 3 weeks playing and its loosened up a little BUT my questions are;

1. Can I have both these subs in a shared chamber or should I do separate chambers?

2. Does those plastic spacers on the top plate of the magnet so space it down really help with cooling? Because they both have amps for them and the amps are the exact same in every way but the new model stays cold and the old model gets warm after a while.

3. A, Why does the newer sub have more excursion at higher tones than the the old model? (like the new one is flexing 20mm and the old model is flexing like 8mm)

3. B, But the new sub flexes less at lower tones compared the old model? Does it just need to loosen up some more?

And yes I know my box only has a 1 layer baffle, but I ran out of money for MDF for the second layer, but that was a like a week ago, its braced now with 2 thick threaded rods and its solid.

NEW SUB

OLD SUB

BOX

There is nothing wrong with running them in the same chamber, they won't "fight" other, in fact they will work together (above resonance) even if one othem isn't getting the same amout or any power...

Is it going to give optimum performance? No.

They both have slightly different T/S parameters and will work best in an enclosure specifically tailored to suit. That is the best answer I can give.

Just a progression in models. We did new spiders and due to putting the spiders down farther on the coil, the baskets have to be spaced up and bumped to keep clearance issues under control.

It will break in over time and act very similar to the previous one.

Happened to me with the double stacked motor design and newer single slug design..

Give it time and they both will play the same.

Hey thanks for you input guys! I appreciate it. I was a bit worried but I understand now. Thanks for the quick replies!