Help with ideas for Altec mid-bass front horn using 416's

[GM]

Thanks guys

How about this from David Haigner?

Mouth is 840 x 650mm.

My drawings is the CAD 3D image....

You're welcome, but no clue without design details, but again, your 70 cm depth precludes a 70-90 Hz XO point at any HF horn matching efficiency/transient response unless you increase the number of low Qt mid-bass horn drivers to further truncate it.

GM