I posted this a while ago in the "open baffle" forum:
Hello to all! I know it has been a while since this topic was commented on but I'm a Tekton OB Sigma owner and I'd like to add a 1st hand report on the speaker:
A little background: I have spent more than 17 yrs enjoying a pair of Apogee Duetta Signatures and I am very familiar with dipoles/open baffles and the concerns of how to get them to perform at their best. As most of you know dipoles have an especially appealing "airiness" or "spaciousness" about their presentation but their designers do have to contend with the bass cancellation issue which, of course, various manufacturers have done with varying degrees of success. I dealt with my Apogee's ultimate lack of low end by carefully blending in a pair of Hsu Research subwoofers and I managed to achieve a quite satisfactory measured and subjective balance in the 2 different listening rooms in which they were used. Both were rather sizable allowing for over 7 feet of space to the rear wall and over 4 feet to the side walls in the 1st room. The 2nd room had dormer openings left and right that were 5 ft deep half way down the side walls on both sides. The speakers were placed at the leading edge of the dormers from the back wall and eliminated what early side reflections there are with dipoles and worked as a diffuser offering the best sound I'd ever had. These speakers did have to go back to the factory in MA twice over the years to have the panels tensioned and the second time they actually replaced the bass panels with an "updated" version less prone to the tensioning issue (so I was told, but that was the last time I had the issue before I sold them).
After a few years with a selection of stand mounted monitors from B&W and Spica (incredible sound stage from these old favorites!) and the Hsu subs. I began to miss the dipole magic and began looking around again for what was available. I was aware of Maggies of course but had found their sound "constrained" for the kind of dynamic music I most enjoy. Then I started reading about this guy in Utah and his Pendragon and Enzo speakers and how popular they'd become for their price. When I looked at his website I saw the reference to his OB Sigma and his brief description. Now, you can poo-poo his comments if you like but the idea of cancellation of low end behind a baffle of sufficient width fading carefully into the upper bass/lower dipole midrange made a great deal of sense to me. Shortly thereafter he offered these speakers at nearly half price with a 30-day return policy. With no risk I ordered a pair to see what it was all about.
I've been playing with these for nearly a month now. They work rather spectacularly IMHO, but their are a few issues I'm looking into dealing with. Walking behind them as they play is revealing...the "initial" bass is gone in the near field. As I pass into my bedroom behind and across a stairwell away it returns as carryover from front firing bass no longer cancelled wafts into the house. The fairly wide baffle (17") does tend to focus the tweeter's output to a fairly narrow sweet spot and, though the baffle edges are rounded, I suspect diffraction off the edge a bit. A little playing around with some F11 wool felt strips should ameliorate that issue and, in black and carefully cut, I should be able to retain the speakers stark but appealing "industrial" simplicity. I really don't give a damn what they look like as they're in a room dedicated to only music and usually totally blacked out
I'm keeping these for sure as they have again returned to me that wonderful dipole airiness, solid slam factor that dynamic drivers do so well (excellent Seas drivers) and SOLID bass performance. Like all speakers I've ever owned they do benefit from a little careful room treatment - bass traps, diffusers, and absorption panels here and there.
Update: moved into recently vacated basement space (goodbye son, have a good life!) - it is smallish, only 14' by '21' with a somewhat odd shape prompting me to set up angled about 20 degrees from the central axis of the room placing the listening chair in a nicely open area where the stairs lead up on the left leaving me with about 8' either side of my head and 6'+ behind. Shelves at the other end behind speakers contain a mixture of diffusing items and mom's old pillows dispersed fairly randomly until I got the right "sound". With toe-in and the natural low level of side dispersion common to dipoles I've got things sounding quite good but more to do.
1st action based on years of dealing with baffle diffraction was F-11 .5" wool felt around the excellent Seas soft dome tweeter on this 17" wide baffle - inch between tweeter, 4" to left and right, 7" below...looks like a rectangular beard on the tweeter. Immediate smoothing of treble response - those that have used felt know exactly what I mean.
Spacious sound, balanced, coherent, detailed with no etch - well recorded voice floats in a deep & wide soundstage. From Eva Cassidy to Mary Black, Clark Terry scattin' to even Mark Knopfler "singing", anything well recorded sounds, well, well recorded! Conversely bad recordings tend to sound worse than you remember. Btw Clark Terry's "Portraits" CD (Chesky JD2) and Dire Straits "On Every Street" CD - one recorded "audiophile", one a masterful mixing room concoction, both outstanding through these Eric Alexander creations! Alison Krauss, ridiculously good - Tingstad & Rumbel, sweet and airy - Fourplay, stunning - Aaron Neville.....well, let it suffice to say that if it's well recorded it sounds remarkable!
Right now upstream is a garden variety Adcom GFA 555 II (never have understood the negatives on this truly fine Nelson Pass designed amp...I think it's quite good for the $) driven by a HK dvd48 through a dBX CX1 pre. I do have a pair of Hsu Reseach subs through a Rane active xover @ 70 Hz supplementing @ low level the Sigmas running full range.
Check Terry London's review at hometheaterreview.com. He explains in better detail the technical details of the speaker's design. Also I should note that Eric at Tekton is releasing a newer version of the Sigma OB soon....I can only imagine!
