Quote Originally Posted by bfish View Post
I'd suggest measuring the T/S parameters on your 416s before settling on boxes for them.

AFAIK, the current kits are the one-size-fits-all 416C kit Altec was using when they quit........

Another option to use what you have if they don't match well enough is a 4-box MTM.

Doing a passive XO for a 3-way with mid and HF horns of such vastly different dimensions... I wouldn't go there.
Agreed, though not a big deal in most sealed apps. Vented is a different matter since even the dissimilar path-lengths between the drivers and vent accepts power sharing. In extreme cases, I've seen one woofer 'hog' most of the power, causing it to audibly distort due to both thermal power compression as well as over excursion while the other woofer is mostly acting as a passive radiator. For most HIFI/HT apps using large HE woofers though, it's normally not a concern.

Still, when the desired driver/vent layout allows it, putting each driver in its own vented 'cab' is a good plan if for no other reason than the divider makes for a much more rigid cab and each can be individually tuned/optimized.

Bummer, guess if I ever need one of my 515Bs re-coned I'll have to sell them.

4 box MTM?

Yeah, been there, done that way back when and why I swapped 805/288 for 511/802 to get a satisfactory HF response and later adding a second pair to get the larger horn combo's more robust mids to 'have my cake and eat it too'.

GM