First image is the "Stock" frequency response of the Alpha 6C. If you mouse over the image you will see the frequency response changes brought on by the addition of 5 strips of 3M foam mounting tape on the dust cap. 

CSD graphs of stock driver and driver with foam tape on dust cap.

The foam tape strips on the dust cap

Next, we start with the frequency response of the Alpha-6C with the foam tape on the dust cap. We add carpet felt outside the spider and on the inside of the basket legs. Mouse over the image to see the changes made by the felt.

CSD showing the changes caused by the felt in the basket

Image of carpet felt in space between the spider and the frame.

And image of carpet felt on basket legs.

Image below is the frequency response of the driver with the 5 foam tapes on the dust cap and carpet felt inside the basket. Next step adds 9 small foam squares on the back side of the cone roughly half way between the voice coil and surround. Mouse over the image to see the frequency response change brought on by the foam blocks. 

Image of some of the 9 small foam squares stuck to the back of the cone.

Overall, some interesting experiments. Need to digest all this information and try some more experiments. Only had the drivers for one afternoon though... Have to get more to continue developing.