passive radiator testing

[mhtplsh]

How to test passive radiator?
I saw the following data of commercial passive radiator.
How they hv measured it?

[mhtplsh]

Here is the data

[Ron E]

I think I have posted a procedure here.
Yep:
Passive Radiator measurements?

[mhtplsh]

Thank u very much Ron E.
I will use ur method.

[mhtplsh]

I refer to Brians's website http://www.diysubwoofers.org. about
Passive Radiator.

It is mentioned :
To measure the resonance frequency of the passive radiator, install it
in a free-air baffle (e.g. the box it's going in, without the driver
in place), then hold a driver, driven by a sine wave generator, as
close as possible to the passive radiator, then vary the frequency. At
the passive radiator's resonance frequency, you should see the
greatest peak to peak excursion of the passive radiator.

I understand that free air baffle means just one sheet of any plywood
with hole to mount driver.
Is this correct.

[Ron E]

Originally posted by mhtplsh
Is this correct.

It could work, not sure how apparent the PR motion would be, though. If you did the test twice (once after adding mass enough to shift Fp by 30% or so) you could also calculate Vap, theoretically...

If you are daunted by the testing, simply calculate the mass of air in a port with the same diameter (with the same box volume and tuning you want) and try to make sure that the PR weighs that much (in total) should suffice.

[noah katz]

"Here is the data"

That's a very low Qms, which will attenuate output significantly.