Can someone explain how a.FHXL "works"? Basic acoustic engineering?

[planet10]

Some of these have been covered

1. This cabinet is to get better bass from a smaller driver, and that is its primary purpose?
2. Would all frequencies above the bass frequencies be created directly from the driver, with the cabinet having little impact, and the cabinet is designed to try to ensure this?
3 What is the approximate frequency where the transition to cabinet enhanced bass occurs?
4. What is the approximate lower limit to bass frequency in ideal room conditions?
5. What frequency is the cabinet tuned to, or if this doesn't make sense, what does tuning a cabinet mean?
6. Would the cabinet perform roughly the same if it were a long wedge of the same dimensions, instead of being folded?

1/ the basic purpose of the box is to isolate the rear output of the driver from the front. If we put a “hole” in the box it is possible to use that energy from the back of the driver to extend the bass further (not free thou). A horn is typically large, a quarter-wave resonator, and shaped to get gain in the bass.

2/ the shapes of the cabinet will affect the way higher frequencies, but its intention is to enhance the ability of the loudspeaker to reproduce bass

3/ somewhere 250-300 Hz.

4/the lower limit of the horn is determined by its geometry, and in the case of the FHs the wall/corner the mouth loads into is an extention of the horn mouth, so trying to estimate bass extention without knowing exactly how they fit in the room is really not possible. Bass extention gets into the low-mod 30s F10 (FHXL).

5/ the shape and size of the cabinet determine that. As in 4

6/Yes. But it is not pretty or practical :^) And it makes it difficult to take advantage of the wall/corner loading.

dave

 

[GM]

Note, it was NOT designed as a bass reflex. Let's het this straight.

Right, it's a mass loaded [vented] TL with 1/4 WL pipe action adding some acoustical damping to the vent whereas a bass reflex alignment is presumed to have a ~uniform particle density, so just one air mass 'slug' exciting another one.