Quote Originally Posted by Phil-G View Post
They look good without the vanes. Who ever took them out did a nice job.
Yep.

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Quote Originally Posted by GM View Post
Improves the mids, mucks up the HF to my ears. Better overall to just remove the little vertical brace, cut the vane welds and use vibration damping inserts like Altec did near the end of the 511's production. Among other things, it takes the 'starch' [stress] out of it form welding. If any 811s were done, I don't recall learning out it.

IME tweaking these things, by far the most audible gains were had in matching [align honing] the driver/throat out to where this conical HF WG joins the square flare, replacing the cardboard gasket with a proper sheel metal one using wax paper or similar thin, yet ultra sealing, gasketing material [get it right and wheel bearing grease suffices], damping bell modes with the vane inserts and proper baffle mounting to load the driver lower as it was originally intended along with a foam mouth extension that's somewhat larger, deeper than the one developed for the M19 and later replaced fiberglass insulation on other models to quell the mouth's eigenmodes, which reflect back to the throat causing most of the 'ripple' one sees in all but the most smoothed response plot.

GM
I did the honing, wax paper gasket, removing the vertical inserts in the throat, and damping, All of these tweaks provide audible sonic gains.