I am happy to report you that I've succesfully completed my Acapella
project. Main difference to your design was to use Seas "Millenium"
T25CF002 tweeter and make modifications to crossovers. You can see also
that I used L21RN4X_P as a woofer. So in a sense this is a slight
adaptation based on your designs.
I initially built a prototype cabinet for measurements and LSPCad
simulations and after I was happy made the commitment to build final
cabs. I've painted them glossy white and polished the surface to remove
most of "orange peel" surface. This is my first major DIY build and
first painting project as well so I am very happy with results. Sound
and stereo image of open baffles is very different from typical boxed
speakers I am used to.
I've built into tweeter crossover possibility to change attenuation
resistors, so I am able to balance out the sound to my liking. Only
minor detail from measurements is the 3db peak at 2700hz crossover
frequency. I used 0.33mh coil as per your dZ comments and LSPCad
simulations showed it to work. Now I'd be inclined to try it with 0.25mh
to see if the peak flat's out. Is there any concerns that come to your
mind doing this?
Bass performance and dynamics from Acapella are very impressive. Port is
tuned to 32hz and -3db point is around 26hz. One question is that do you
use or recommend any other filling to bass cabinet than bitumen mat and
foam attached to cabinet walls? I've added some extra acoustic cotton
filling, but I do not think this will hurt anything.
Please find some images below and as a attachment. I plan to do a bit
more comprehensive DIY report when I've composed all the pictures. I had
a lot of help from Finnish DIY community (Hifiharrastajat Ry) doing
measurements and working surface finish.
Also my build thread (in finnish) is here:
Thank you very much for your design and help! Please feel free to
include this with images to your builders response page, if you like.
Best regards, Janne