I stumbled across an Altec 825 on 3D warehouse, and started to wonder how would modern driver perform in such enclosure. Since I had data for Celestion TRUVOX TF 1530, I started Sketchup and Hornresp, and this is what I got.
This is 3D model from 3D Warehouse
Enclosure from ebay. In my simulations I modeled box as Altec 828, with closed front pole.
Reverse engineering using advanced centerline method
So, after analyzing enclosure, I made compound horn in hornresp, which looked like this:
This is power response, rolloff begins at about 55-60Hz, as predicted.
Impedance curve.
Compound horn model.
I was wondering if I can make things simpler. Therefore, I modeled Compound horn as Exponential horn + BR box. It looked like this:
Not exactly the same, but very close.
Impedance curve also very similar to previous model.
Simplified Compound horn enclosure.
I decided to use simplified model. After litle tweaking of BR port, with final area of port of 500 cm^2:
-3db point is below 40Hz.
Impedance curve looks more like BR now.
So much for now, stay tuned...
