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

See my post "Crossovers for Delta15 @ 700 Hz, Beta12LT @ 15kHz? " below. There are others as well; just take a look.

I tried Wayne's crossover and the KSN1038 but the piezo didn't seem loud enough to me. I was thinking of trying the more sensitive KSN1177--it's basically two piezos side by side!

You might want to redo the PiAlign calculations with the "new" Beta12LT specs off the eminence site. The data file in the PiAlign program uses the "old" specs.

Good luck,
Jeff

...but my problem persist....

> You used 2.4 as as cabinet volume but you should have used 2.4 x
> 1728 to convert it to cubic inches. You must use the same terms
> throughout - If inches in one place then inches must be used
> everywhere. You can use feet if you wish, but then the port
> dimensions must be in feet for "Lc" and sq. feet for "Ap".

I suppose I am wrong but I cannot find where :-(
Question is : what is eqation Fre = 1/2pi * sqrt(Ap/VeLc)
calculating?

Using your values and formules from Pi white paper,
Ve = 2.45 cu ft = 4242 cu in then
Dp = 2.5" => Ap = 4.9 sq in
Lp = 2.75" => Lc = 4.872 in

Fre = 1/6.28 * sqrt (4.9/(4242*4.872) )= 0.00245 Hz :-(((

Thanks in advance,
O'Tor

> See my post "Crossovers for Delta15 @ 700 Hz, Beta12LT @ 15kHz? "
> below. There are others as well; just take a look.

thanks for the type...

> I tried Wayne's crossover and the KSN1038 but the piezo didn't
> seem loud enough to me. I was thinking of trying the more
> sensitive KSN1177--it's basically two piezos side by side!

Thanks for your opinion!

> You might want to redo the PiAlign calculations with the "new"
> Beta12LT specs off the eminence site. The data file in the PiAlign
> program uses the "old" specs.

Wayne allready used this new values (Qts/Fs = 1.51/45).

How is your Beta 12LT performing ?

O'Tor