Acapella SEas, built by Janne, Finland
Copyright 2014 © Troels Gravesen


Dear Troels,
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