I've finished my 3 cu ft sealed sub and was wiring my 15" SI D2 in series for a 4 ohm load on my amp, also at same time wired my 18" SI D2 for 4 ohm load.
(I just got my 4 cu ft flat pack so this weekend just starting assembly later today)
I noticed the underside of the sub driver cone is covered with paper, for lack of a proper descriptive it simply feels like paper mache.
What caught my attention is the 18" backside paper is very smooth and consistent, while the 15" backside felt wavy and possible some air bubbles even, is this normal?
Is there any reason to contact SI and ask them?
18" SI D2, pretty smooth and consistent.
15" SI D2,this picture does not capture it but there are distinct waves/squishy feel spots compared to the 18" driver.