Pi Aligned Afterburner & Port Calculation


Hello,

I'm just started to build a Pi-aligned version of Thorsten's Afterburner. I haven't yet the RS tweeter, but I will try the piezo - maybe KSN1038 ? May this be a good match for the 99dB of Beta 12LT ? I used the values given by PiAlign soft, the same as Wayne gave in this post.

I tried to re-do the calculation for the port dimensions (I like verify the things before cutting :). Unfortunately it doesn't work as I supposed. For 2.5" diameter port that's 2.75" long I've got 0.1Hz instead of Wayne's 33Hz . More details, see link. What's wrong ?

Thanks in advance,

O'Tor



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