@mrdecibel wrote:
horn loading a sealed woofer? I do not understand. My AR 3a pair have a sealed woofer system. My best, MrD.
The 15" woofer in your La Scala’s is placed in a sealed chamber from where the front wave of the woofer cone fires into a slot (i.e.: a compression) and then the wave shoots into the back wall divider section and continues through the expanding horn to either side. That is to say: the front wave of the 15" woofer is the only thing loading the horn, whereas the backside of the cone looks into the sealed chamber and is therefore not exploited. Classic front loaded horn approach.
The 12" woofer in the AL6 La Scala’s on the other hand sits in a ported chamber, and so not only the front wave of this woofer (which also fires through a slot) is loading the horn, but as well the back wave of the cone that releases its energy through 2 ports. That’s the same trick they’re using on the few years old, domestic version of the Jubilee’s.
I’ve seen a version of the La Scala’s (likely a DIY variation) that is ported in addition to its horn-loading, but those ports were visible on the front side and so not firing into the horn itself.