A quick recap and update.
The reflection at 700Hz is from the basket posts. It comes from the large flat portion facing the underside of the cone (6 posts). Closed cell foam works best (black in colour (here in Canada we spell color (colour))), open cell foam (white (this we spell the same)) doesn’t work.
My crossover is a series crossover, so don’t look at my inductor value’s. Parallel crossover’s are different.
I’ve been using copper foil air core inductors for testing. Now that I’ve narrowed down my value, 2.7mH, I’ve been listening to a lot of music. I remembered I have a couple cored inductors. I decided to listen to a Mundorf Vacuum Impregnated Zero Ohm Cored Inductor.
Let me first recap what I’ve found over the years. For woofers, the only type of inductor I will use is cored. So no air core inductors. The cored gives me tighter and more impactful base. For tweeters, and mid ranges, air cored is best.
What about for a mid woofer. My design is a 4-way. So my TD6M is responsible for 150Hz – 1200Hz (even though is cross’ at 1800 (still working on that). Yesterday I installed the cored. There is a fullness in the mid base with the cored. Unfortunately there might also be a slight drop in articulation higher up.
I will listen for a few days, swap the air cored back in, listen, and report what I think I hear.