Of course the most important measurement was cranking up some music and giving the speaker a good listen. The Carrera’s passed that test with flying colors. Awesome. But being and engineer at heart, I would love to be able to quantify “sounds great”. Well, easier said than done. Partly, because it is difficult to measure, especially at lower frequencies. And partly because of that grey stuff between our ears: “sounds good” is by nature subjective.
Anyway, for now, I’m settling for a few measurements that confirm the build is more or less in line with the design. And looking for any red flags that may indicate mistakes that I made.
I ran an impedance sweep using the Dayton Audio DATS audio test system. Everything looks about as expected.
The bass reflex port I used was 9″ long, giving the expected box resonant frequency (fb) right around 38Hz (at 0° phase angle). Per Paul’s comments, a 7″ port should increase that to around 43Hz, but I have not tried that yet.
The right and left speaker were closely aligned. Impedance and phase looked roughly in line with the original design. The center channel response below 100 Hz is a bit different, but that is not surprising since the geometry is different and the bass reflex port is on the side instead of the back.
I don’t see any ripples in the curve that would indicate internal cabinet reflections.
I’ll circle back to some frequency response measurements when I have a chance
