The opening was 4.5 inches with a roughly 5 inch step around the hole.
Here's a photo of it with the baffle installed, made from a threaded cap for 4" ABS DWV pipe. It helps to have a lathe or access to one. It's thoroughly stuffed with itchy fiberglass insulation and doesn't ring when I tap on it. It's the focus of my first foray into measurement so I will likely post some measurements when I figure it out.
Subjectively the thing sounds better than I expected for something so small and inexpensive.
Here's a photo of it with the baffle installed, made from a threaded cap for 4" ABS DWV pipe. It helps to have a lathe or access to one. It's thoroughly stuffed with itchy fiberglass insulation and doesn't ring when I tap on it. It's the focus of my first foray into measurement so I will likely post some measurements when I figure it out.
Subjectively the thing sounds better than I expected for something so small and inexpensive.
Attachments
Here is a set of measurements by sine sweep, my family is feeling tortured 
by my new apparatus.
I measured without EQ, with and without mic cal file, and after applying some BSC and two parametric filters to minimize the large peaks at 8.3kHz and 15.5kHz
I can't listen to music until morning so no opinions on the eq'd sound yet. I'm very very interested in learning how to measure phase and to see how badly the digital crossover affects it compared to passive crossovers.
by my new apparatus.I measured without EQ, with and without mic cal file, and after applying some BSC and two parametric filters to minimize the large peaks at 8.3kHz and 15.5kHz
I can't listen to music until morning so no opinions on the eq'd sound yet. I'm very very interested in learning how to measure phase and to see how badly the digital crossover affects it compared to passive crossovers.
Attachments
