Originally Posted by
Mr. Widget
Before we began our horn comparisons we wanted to explore the low end capabilities of the 2431 and 2435HPL compression drivers with their small back cap and compare them to the 435Be with it's large back cap. To do this we mounted the three drivers on a 500Hz 1.5" throat horn I have that is about the size of an Altec 511. It is not a CD horn so it's on-axis response is reasonably flat without compensation.
Here we see that the low end performance of the 435Be, 2435HPL, and 2431 are all quite good. It would seem that the larger back cap isn't necessary for performance below 1000Hz. We did not do any listening tests or power tests measuring distortion, but the initial measurements were surprisingly encouraging. I am not sure if it is due to the back cap or other tweaks, but the 435Be did exhibit, albeit by a small margin, the flattest overall response of the three.