Ported midrange in a 3way

[augerpro]

So I'm looking at my Onix Rocket 760s and see the midrange is ported. What would be the point of doing this? Considering they are probably crossed at 300ish Hz.

The mids may share the enlosure with bass, but I have to look and see.

[joecarrow]

The excursion at the tuning frequency is reduced. This could be used to decrease excursion and distortion at higher volumes. Of course, there is an increase of group delay around tuning as well, so that's probably why you don't see this used very often.

[augerpro]

Do you think the tuning frequency would be high enough to matter though? These are 5.25" drivers, probably crossed at 300Hz or so. i would think the box would be tuned much lower, probably similar to what an MTM design would be using these drivers. Crossed at 300Hz I don't think you would have much excursion left to reduce at say 80hz. Or not?

[Landroval]

Depending on the steepness of the crossover slopes, a 300Hz x-o point means that the driver is still putting out a lot of stuff in the 100-300Hz range. The venting might be there to shape the output of the midrange. Just a possibility.

There's a point in reflex tuning the midrange when x-o point is very low (e.g. Verity Audio), but seems plain stupid with small midranges and high x-o's.