Passive Speakers Rev. 2

Updates

Z-Offset Fix

With the original design, the tweeter and the woofer were not aligned correctly. The tweeter itslef was firing at a distance in front of the woofer. If the acoustic centers are misaligned (different Z-offsets) between the woofer and tweeter, the phase relationship between the two changes. This causes constructive or destructive interference (or distortion), depending on frequency and phase difference. To fix this, the tweeter mounting area was recessed back half an inch. While a 1/4 inch ring was created to bring the woofer forward. Now both drivers are firing on the same plane.

Internal Dampening

Another design detail that was overlooked initially was the actual size of the cabinet. The woofer I selected was too large for the enclosure. This cause the resonant frequency to increase, loosing a bunch of low frequency response. To simulated a larger enclosure, I added a layer of dampening foam to the interior.

Refined Port Distance

The port cylinder distance was also refined to give the desired bass response. Previously its reponse was overlapping with woofers response, causing the design to miss out on lower frequency coverage. The combination of the this and the internal dampening gave the speakers more low end, that was previously missing.

Results