Interesting passive radiator module

[bassl0va]

Came across this today.
Interesting design and would probably be fun to play around with. Probably more use to the home theater crowd though, and even then passive radiators aren't popular.
Not sure the one with a sub and PR mounted on the same module is a good idea, but could be interesting if it was 2 subs.

Of course you could just build this sort of thing in with traditional drivers/PRs when making an enclosure, but it's cool all the same

[Triticum Agricolam]

Interesting.

[hispls]

The big problem with passive radiators vs. port is that a port costs either a 10$ stick of sono tube/PVC or less than 10$ worth of wood, glue, and screws whereas Passive Radiator would start at 50$ and some time and that's assuming you just buy a frame, spider, and cone and use glue and lead shot to add mass.

If space and the ability to quickly change tuning by screwing on weights is worth the premium price it's a good option.

That all said I wonder if the passives radiating out through that narrow opening doesn't begin to act like some sort of 6th order or if their behavior in that chamber is figured into the design?

[bassl0va]

The big problem with passive radiators vs. port is that a port costs either a 10$ stick of sono tube/PVC or less than 10$ worth of wood, glue, and screws whereas Passive Radiator would start at 50$ and some time and that's assuming you just buy a frame, spider, and cone and use glue and lead shot to add mass.

If space and the ability to quickly change tuning by screwing on weights is worth the premium price it's a good option.

That all said I wonder if the passives radiating out through that narrow opening doesn't begin to act like some sort of 6th order or if their behavior in that chamber is figured into the design?

Yeah exactly and for the extra money you could go for more cone area or a better sub. Plus there's not really much point in car audio unless you want to start doing demo with organ music or movies. I don't think there's all that many subs that work well tuned low in a tiny box either. They're handy for HT subwoofers for those who have to worry about WAF though haha.

Yeah I was wondering about that too. I think it'd appear as more complicated than just extra cone mass since it's practically a port.

I'm thinking a 4th order wall full of these, who's up for it?

[ShadeTreeMechanic]

I think they invented a solution in search of a problem.

[meade916]

whether or not it's practical to use a PR like this, i don't know. But what i do know is i love all things car audio. I love cool gadgets. I would love to hear this and see if it is any good

[Triticum Agricolam]

...

That all said I wonder if the passives radiating out through that narrow opening doesn't begin to act like some sort of 6th order or if their behavior in that chamber is figured into the design?

Having the PRs in a manifold like that is definitely going to have a low-pass filter effect, like a 6th order bandpass box. The frequency that it filters output above is probably going to be high enough to not matter though.

There are sub box styles that mount the subs in a similar manifold fashion for sound quality reasons, they are pretty interesting IMHO. Google "push-pull slot loaded" subwoofer or PPSL and you will find lots of info on them.

[ShadeTreeMechanic]

I have seen ht subs manifolded in an ib setup installed in a basement below the listening room. The open end of the manifold was put up into a hole in the floor of the listening room.