Calculate Q and F of sealed subwoofer

[Unklejoe]

Hello,

Is there any way to easily calculate the Q and F0 of a sealed subwoofer from its measured frequency response?

At the least, I know it can be done manually by iterating over the values (and plugging them into the Excel sheet from MiniDSP) and checking which ones produce the same response, but I’m wondering if REW can do this for me?

I also tried using the measured impedance and calculating Q and F from there using the equations provided on the Linkwitz website, but my calculated values seemed off.

For context:

I have a sealed Dayton UM18 in one of those 4 cubic foot flatpack sealed enclosures, powered by a Hypex FA501 DSP amp. I’m planning on using a Linkwitz transform to extend the frequency response a little bit and correct the Q to 0.707, and it would save me a lot of trial and error if I knew the current Q and F since the Hypex filter design software allows me to plug them in to derive the exact “asymmetric shelf” (i.e., Linkwitz transform) filter that I need to achieve the desired response.

Thoughts?

If this can’t be done, I’d be willing to donate a small amount of money towards a feature request, if that kind of thing is acceptable.

Thanks!

 

[John Mulcahy]

Have you tried the TS params calculator? You can get Fs and Q results from a single measurement.