midrange back housing

[Mosquito]

Hi every one
For a three way system with cone midrange, I was wondering if a back volume shaped roughly like the drawing, and filled with appropriate material, will succeed in diminish wave return through the cone itself.
Or maybe just a 90 deg sewer pipe section(one end closed) will do the same and there's no need to bother.?

 

[Inductor]

Nice. Like!

 

[Lojzek]

Mosquito,

put some stuffing material in a cuboid chamber and you won't get any
standing waves coming through the cone. You can check if it works by
measuring impedance and FR. Any impedance wiggles at the natural
frequency od the chamber dimensions showing on impedance means
it still exists. The FR graph showing chamber standing wave looks like
a sinusoid.

 

[infinia]

standing waves in a tube, the dominate nodes still exist not affected in 2 of 3 dimensions? do you need the xtra volume for the mid or is the bend gonna help non parallel walls.

 

[Mosquito]

Hi, I understand what Lojzek said, not so sure I catch infinia's post. The whole idea (maybe out of a bit of naivety), was to guide the back wave to somewhat a trap, where it can't travel back.(and with a lot loss of energy making through the filling material) The drawing was just a concept, w/o any optimization of dimensions and angles.

 

[markbakk]

Lojzek's right of course. Unless you have about every other aspect on enclosure geometry and it's acoustic consequences optimized, don't bother too much about the illustrious back wave effect. Most people I see struggling on that don't seem to mind that the baffle sides of their enclosures often form near perfect secondary sound sources (diffraction) which they sometimes even claim to be of no effect as opposed to that back wave thing.

 

[infinia]

trapping the energy? why don't you let the tube exit to the back of the box since the tube volume matters little or edit> maybe you haven't got that far into the design,

 

[Mosquito]

Ok, I got it. What I was told here makes sense to me. A bit of myth busting is useful too.
Infinia, that idea came to my mind but, as it is going to be a box with removable back panel, that thing seemed complicated and unpractical.
This one will be something like Leach's Gatech three way box, whith some twists here and there ( for the diffraction at the sharp borders) , nothing more.