crossover networks for waveguide loaded tweeters?

[kappa546]

Most of the designs i've seen incorporate a simple 1 cap network to shape the WG boost down and achieve a 2nd order acoustic crossover. I noticed that all of the SP tech speakers took a little different approach and accomplished a 4th order LR acoustic xover at a much lower frequency (6-800hz). http://www.4sptech.com/version2/genprod.html

I'm new to crossover design and was wondering how one achieved this type of response? I'm curious because i think i'd like to experiment building an MT using a Dayton RS270S and a WG loaded D26NC55. while i'm being a bit outrageous, how high will an Aura NS10-513 remain pistonic? :E

Thanks in advance

[rc white]

Details of an equalizing network can be seen here..

http://sound.westhost.com/articles/waveguides3.htm

In this the series resistor is chosen to provide the required amount of low end attenuation.
The capacitor is chosen so it has the same reactance as the Ohmic value of the resistor at the point where the frequency starts to roll off.
If the shunt leg is incorporated it gives a very near constant impedance characteristic.

[Jed]

Most of the designs i've seen incorporate a simple 1 cap network to shape the WG boost down and achieve a 2nd order acoustic crossover. I noticed that all of the SP tech speakers took a little different approach and accomplished a 4th order LR acoustic xover at a much lower frequency (6-800hz). http://www.4sptech.com/version2/genprod.html

I'm new to crossover design and was wondering how one achieved this type of response? I'm curious because i think i'd like to experiment building an MT using a Dayton RS270S and a WG loaded D26NC55. while i'm being a bit outrageous, how high will an Aura NS10-513 remain pistonic? :E

Thanks in advance

The RS270 is good to about 600hz before harmonic distortion rises to audibility. The Aurasound has low sensitivity and dips at 300-400hz- which was audible when I had my experiences with it, and the D26 has a relatively high Fs and low distortion down to 2K, so it's probably not a good candidate for a lower crossover point than that.