Quote Originally Posted by Tralalalala View Post
Any other people out there that has built or heard Altec Duplex speakers in MDF cabinets ?
Yes.

?? MDF cabs have a low Fs due to their higher mass, damping, usually in the lower mids BW, so tend to ?suck the life out? of some speaker?s critical mids, especially low Qt ones like most Altecs.

If driven with a ~matching impedance or the driver has a high Qt though, the cab?s damping tends to reduce any under-damped driver ?ringing?.

19 mm BB or similar no-void ply OTOH tends to have a high enough Fs due to its extreme rigidity to be above the cab?s gain BW, so only minimal damping is required to keep the driver from exciting the cab, ergo any ?liveliness? in the response is all driver generated and most Altecs are known for their ?liveliness?.

A decent compromise is to make the baffle and top out of 19 mm no-void ply and the rest out of MDF and use some ply scraps to reinforce the MDF panels. If stand or wall mounted, then make the bottom out of ply also.

GM