Watts needed to measure TS parameters for Big Car Audio Subs

[jvgabs]

Hi,

I am planning to measure the TS parameter of the 12" brother of this sub
My audio interface is a Behringer UMC22 and I have successfully built and calibrated the basic jig with 33ohm rsense. I was able to use it to measure an unknown 8inch woofer without weird issues.

Will that UMC22 be enough to drive the subwoofer? If not, how much power from an external amplifier be needed? I am thinking using the built in amplifier of a head unit which I think roughly around 15W.

I would also like to know what was the percentage to target in bringing down the fs of the speaker using added mass method? I read somewhere should be 10% lower fs than free air but not sure.

 

[sm52]

I read somewhere should be 10% lower fs than free air but not sure.

This is true. Almost. In my experience, 86-87% of the estimated mms.

 

[jvgabs]

This is true. Almost. In my experience, 86-87% of the estimated mms.

I added 149grams, and this is what it looked like. another bump appeared around 140hz. is this considered normal? this is an an undocumented PA speaker

this

 

[sm52]

another bump appeared around 140hz. is this considered normal?

This is the resonance of the measuring setup or speaker basket.

What mms did the measurements show?