Passive Radiator question.

[Jimi77 5,000+ posts]

Today I learned about enclosure orders.

A standard bass reflex is considered a 4th order.

I learned that the bass roll off arguably defines the order of the enclosure.

Would this passive radiator represent a higher order enclosure? Because of its steeper roll off?

Passive radiator acts like a port, still 4th order. Additionally, roll off could be altered by changing tuning frequency, but it's still 4th order. I can alter the roll off a sealed enclosure by making it really big or really small - still 2nd order. The shape of the curve and roll-of on a 4th order bandpass can also be altered by changing tuning frequency. In the case of bandpass it's possible to have 2 different roll offs.

 

[SlugButter]

You know what. I could be wrong about dual passive radiators making it a 6th order bass reflex. The response curve does change using dual passive as opposed to 1, but they are pushing and pulling as a team. I think it's a 4th order bass refllrx.

 

[Evyn1]

Today I learned about enclosure orders.

A standard bass reflex is considered a 4th order.

I learned that the bass roll off arguably defines the order of the enclosure.

Would this passive radiator represent a higher order enclosure? Because of its steeper roll off?

The “order” is describing the energy storage. its like a spring with a weight on the end (2 orders of stored energy), or a piston with a push/pull component. The coil(spring) is stored energy and the mass of the cone is stored energy, so a sub in a sealed box is a 2nd order (2 components of stored energy). Adding a port acts like adding a second “piston” with a push/pull effect, making it a 4th order. A PR is the same as a port essentially, having a spring and a mass(the cone) it adds 2 orders of energy storage, making a PR enclosure a 4th order. Adding 2 PRs to a single sub would make it a 6th order bass reflex enclosure, not to be confused with a 6th order bandpass enclosure.

Super interesting!

Does this 6th order apply if there are 2 ports? Compared to 1 port (4th order)?

 

[Jimi77 5,000+ posts]

You know what. I could be wrong about dual passive radiators making it a 6th order bass reflex. The response curve does change using dual passive as opposed to 1, but they are pushing and pulling as a team. I think it's a 4th order bass refllrx.

I think 4th order is correct. The 2 PRs just replace a larger single PR. I guess if tuned the PRs to different frequencies, then you could change the order.

 

[SlugButter]

Super interesting!

Does this 6th order apply if there are 2 ports? Compared to 1 port (4th order)?

a 6th order has the sub (2 orders) a port (2 orders), and a port tuned to a different frequency than the other port (2 orders). There is also an 8th order, which is a 3rd port tuned to a different frequency than the other 2.

 

[SlugButter]

I think 4th order is correct. The 2 PRs just replace a larger single PR. I guess if tuned the PRs to different frequencies, then you could change the order.

Yeah. That’s correct.

 

[Evyn1]

A 4th order bandpass/passive radiator. With the PR 18” would it sound more like a 12” Sub or a 18”Sub?

Because a 718 could be a better bass reflex for music. Like chopped and screwed rebased.

XCLSV Has quality youtube Rebased Songs. The music reaches lows!

 

[Jimi77 5,000+ posts]

It'll sound like a 12" sub in a bandpass enclosure