Oppirahat was my first attempt of doing a very serious high-end speaker. A tailor-made one all for my own needs. I wanted to create an active loudspeaker which would sound crystal clear even at low levels and have radically different form factor. The project was done during Autumn 2009.
Oppirahat is a Finnish expression for the costs of initiation to a profession or other aspiration. Given that I had rather little experience on speaker design, the components I used were an order of magnitude too fancy. The ceramic drivers by Accuton sound fantastic but require very skillful cross-over design and acoustic measurement in order to reap the maximum rewards. The amplification and signal processing was done with Hypex AS2.100 DSP plate amp which is an amazing piece of hardware. At least when it works.
The enclosure design was done with cost-no-object principle. I wanted to give My fancy high-end drivers the best possible conditions to work in. Box design is a vented 16 liter enclosure with a down-firing port. It has diffraction optimized curvature on the facade and abundant diffuser shapes for breaking echoes inside the box.
Enclosure is laminated from CNC-cut layers of 21mm birch plywood, 42 of them per speaker to be exact. This method gave Me a total freedom of design but came at a cost. The initially good idea of assembling the layers with glued-in wooden rods quickly backfired as the plywood started to shrink in the dry indoor air. Small gaps emerged between layers as the rods prevented even shrinking of the stack. It took ridiculous amount of time and filler paste to seal these gaps. Sanding and polishing the boxes also took many more hours than I dare to count.
All in all, the project was successful in its goals. It sounded almost as good as I wanted except for the bass which didn't quite have the punch I was after. I imagined these to be My long time companions for the years to come. This of course couldn't be further from the truth. As I really got sucked into the topic, new projects and purchases would soon replace these speakers...