Source site fully documenting the build: http://www.troelsgravesen.dk/Jenzen-SEAS-ER.htm A couple of months ago I built a pair of Jensen ER speakers from Troels Gravesen's website linked above. Given my room size I went for the slightly smaller ported design that is 360mm deep. Now both they and I have had chance to break in I'll write a little about them. In my case usage is about 50-50 audio and AV, and IMHO these speakers are equally at home with both Home Cinema and Music duties.
For some time now, I've been running a pair of high quality bookshelf speakers based on the Seas Mimir design. Apparently, they are named after the Nordic god of Wisdom and Knowledge, I cannot disagree and with each listening I like them more and more. I've run them off both Roksan and Arcam amplification and I've really liked the sound from each. Many people think that when building speakers, the most important thing is the drive unit, but there are many concerns: the quality of the crossovers, the cabinet construction and the stuffing used.
Having built several speaker set-ups and amplifiers when I was younger I had got out of the hobby for quite a number of years. However, this build was back in about 2011 and since then I've built a few much better units. However, this is still kept here for completeness. Why I hold this view? In a small room I think it can be difficult to get the right balance between mid to high frequency staging and concentrating the low frequency response near the user.