Does this kind of dual opposed config cancel vibrations?

[lowerFE]

The standard dual opposed configuration is fantastic at canceling out cabinet vibrations. But what if, say for depth limitation reasons, I need to have this kind of configuration. Let's assume the passive radiators aren't going to be a problem. 

 

W    P

P     W

 

Would this still cancel out cabinet vibrations like a standard dual opposed woofer configuration?

[chrapladm]

You still have drivers moving opposite of each other so I would say yes this will cancel some mechanical induced vibrations. I dont think it will be as good as a regular sealed D.O. but still better than without opposing forces.

[SME]

I can't tell from your picture exactly how you plan to arrange the drivers.  I.e., is it a top view? side view? are the drivers mounted as pairs on opposing sides?  The answer is most likely no.

 

Even if each type of driver is firing in opposing directions, the drivers can create a net moment on the enclosure.  A moment is like a force, except it causes rotational instead of straight-line motion.  Instead, you want each pair of drivers oriented so that the back ends of the woofers point directly at one another.  Why not do something like this:

 

P  <==> P

W <==> W

 

where you have one woofer and one passive oriented vertically on each of two opposing faces with both of one type on top and both of the other type on bottom?

[lowerFE]

I can't tell from your picture exactly how you plan to arrange the drivers.  I.e., is it a top view? side view? are the drivers mounted as pairs on opposing sides?  The answer is most likely no.

 

Even if each type of driver is firing in opposing directions, the drivers can create a net moment on the enclosure.  A moment is like a force, except it causes rotational instead of straight-line motion.  Instead, you want each pair of drivers oriented so that the back ends of the woofers point directly at one another.  Why not do something like this:

 

P  <==> P

W <==> W

 

where you have one woofer and one passive oriented vertically on each of two opposing faces with both of one type on top and both of the other type on bottom?

 

That's a top view, so a woofer and a passive radiator in the front, and a passive radiator and woofer in the back. I did not want to do the standard configuration like you recommended, because W <==> W would make the cabinet very deep. W <==> P would be much less deep since the depth of a passive radiator is much shallower than an actual driver. That's why I'm wondering if this is doable as it can reduce the depth requirement of the cabinet. 

[Ricci]

Even if each type of driver is firing in opposing directions, the drivers can create a net moment on the enclosure.  A moment is like a force, except it causes rotational instead of straight-line motion.  Instead, you want each pair of drivers oriented so that the back ends of the woofers point directly at one another.  Why not do something like this:

 

P  <==> P

W <==> W

 

where you have one woofer and one passive oriented vertically on each of two opposing faces with both of one type on top and both of the other type on bottom?

 

Correct...The original proposed arrangement would create rotational forces. How much is unknown but the rearrangement SME showed should be better.

[MemX]

I guess you could build the arrangement in the opening post but instead add another set of woofers and PRs on top but reversed, so it was a cube and the arrangement shown was on each face rather than being a top-down view - there would be torsional forces across the middle of the box so it would need to be pretty strongly built in that regard, but it would be pretty inert overall, from what I can tell?

 

Plus you'd have double the number of drivers and PRs

[SME]

That's a top view, so a woofer and a passive radiator in the front, and a passive radiator and woofer in the back. I did not want to do the standard configuration like you recommended, because W <==> W would make the cabinet very deep. W <==> P would be much less deep since the depth of a passive radiator is much shallower than an actual driver. That's why I'm wondering if this is doable as it can reduce the depth requirement of the cabinet. 

 

Yeah, that definitely won't work to cancel vibration.  How much width do you have to work with?  Can you put the woofers on the sides and the passive radiators on the front and back?  Something like (top view):

 

+------P------+

|             |

W             W

|             |

+------P------+

 

If you have the width, that could help you reduce the depth even more, and the woofers will interact more favorably with the wall.  You'll still need enough wall clearance for the PR on the back so that the wall doesn't cause it to slot load.  As a rough guideline, I think you want a wall distance of at least (D/4) where D is the diameter of the passive radiator.  So an 18" PR should have 4.5" clearance.  You might want a tad more than that to be safe.  If the wall is too close, then the two PRs will see different loads and will not be truly dual-opposed.

[lowerFE]

Correct...The original proposed arrangement would create rotational forces. How much is unknown but the rearrangement SME showed should be better.

 

Are you saying an arrangement like

 

P  <==> P

W <==> W

 

would not be completely inert like a W <==> W arrangement?