keithtexas100 posts02-18-2017 9:43amKeith, the shape of the enclosure is first designed using SOTA Finite Element analysis modelling tools, then then ultimately formed using a proprietary polymer material.I think it’s just a plastic dish of a specific size, which is likely filled with some damping material (of celestial origins no doubt). Here is a video of the S3; discussion (and picture) of the polymer housing for the midrange is at about 9:45 mark.
https://www.youtube.com/watch?v=6aE3mx9-6-M
As stated above, many manufacturers isolate the midrange in a closed/damped housing or chamber.
You're right, most high end manufacturers isolate the midrange driver using either an isolated module (like Wilson) or midrange enclosure. Magico were using a midrange enclosure for the S5 Mk1 for example, though it was made of aluminium and had a no parallel surfaces. The S5 mk2's custom polymer enclosure takes it a step further and has much lower harmonic distortion.