Tekton OB Sigma Design--What?

gnostalgick · « **on:** 18 Oct 2016, 01:11 pm »

From a Home Theater Review review:

To explain his design theory and the implementation of his strategy, Alexander states, "My open-baffle hybrid concept is easily visualized as the following...place and locate a speaker on a flat panel--a pure open-baffle dipole producing sound on both sides of the panel in equal and opposite pressure and polarities. Next, place a second speaker matching in size on the rear side of the open baffle, locate it within immediate proximity to the open-baffle speaker, and use it to create a short circuit nullification path for all low-frequency content radiating from the back side of the open-baffle speaker. Wire the open-baffle speaker and the nullifying speaker in tandem, so they are moving in the same direction to create an acoustical mass transformer. This process produces a monopole low-frequency radiation pattern that entirely emanates from the front panel, then smoothly transitions into an open-baffle dipole radiation pattern, the attribute of open-baffle/planar design that makes audiophiles drool, from the mid-bass frequencies going up. The standard (classical) embodiment of the invention/design is to dissipate the rear energy produced by the nullification (short circuit) speaker using a secondary enclosure of the infinite baffle or transmission line with long termination. Product development phases proved it was advantageous to incorporate a venting system that increased system efficiency and further extended low-frequency performance."

So what does this do, in simple terms? Or is this just an example of salesmanship hyperbole & technobabble? (Which is not to say they don't sound good.)

JLM · « **Reply #1 on:** 18 Oct 2016, 01:35 pm »

Sounds like dipole for higher frequencies and bipole for the lower frequencies.

But what does "wiring in tandem" and "acoustical mass transformer" mean?

Infinite baffle can only practically be done via wall mounting, which can't be a bipole (but transmission line is mentioned).

mcgsxr · « **Reply #2 on:** 18 Oct 2016, 02:20 pm »

I take wiring in tandem to mean in phase. Though the description sounds more like out of phase.

I cannot comment on the science. Not my bag. I have not tried what is described either.

When I run OB it is simple. Driver on panel. Size panel to suit. Space panel in room to optimization sound.

Then again mine were mostly DIY other than a year with Maggie 1.6's.

It sounds like marketing to me.

Wind Chaser · « **Reply #3 on:** 18 Oct 2016, 03:30 pm »

Quote from: mcgsxr on 18 Oct 2016, 02:20 pm

I cannot comment on the science. Not my bag. I have not tried what is described either.

It sounds like marketing to me.

Whether it be marketing or not, there's only one thing that matters, and marketing has nothing to do with it.

opnly bafld · « **Reply #4 on:** 18 Oct 2016, 09:31 pm »

In tandem = in phase; dipole radiation out of phase with ported box driver.
Infinite baffle = sealed box.

Does it work well?

I like OB bass.

mcgsxr · « **Reply #5 on:** 18 Oct 2016, 09:40 pm »

So push pull isobaric but on OB? Don't get it.

I have absolutely enjoyed OB bass in the past too. But just a simple implementation.

opnly bafld · « **Reply #6 on:** 18 Oct 2016, 09:46 pm »

Ported driver firing up in back.

smk · « **Reply #7 on:** 19 Oct 2016, 03:16 pm »

Interesting technobabble for the clueless. What is URL (webpage) so I can read article in context?

gnostalgick · « **Reply #8 on:** 20 Oct 2016, 01:11 am »

Very positive review overall:

http://hometheaterreview.com/tekton-design-sigma-ob-floorstanding-speakers-reviewed/

Chicken Man · « **Reply #9 on:** 20 Oct 2016, 02:57 am »

I dare say the frequency response would be rather lumpy around the low end and rather odd with just the front firing ports supporting the open baffle section.

C.M

Russell Dawkins · « **Reply #10 on:** 20 Oct 2016, 06:46 am »

I had some respect for Eric Alexander—in fact quite a lot. I thought his designs were clever and effective. I also think the OB design referred to in the first post, the Sigma is clever in the way it partially cancels the rear radiation from the bass driver—if, in fact that is a benefit. I also think the asking price has been reduced to what it should have been in the first place, at $1750. This is a pretty simple looking box.

However, I detect loose techno babble of a kind I find objectionable in the descriptions of the various design principles on his website. I puzzled, for example over his mentioning that the mass of the source of the 41Hz tone from a bass guitar was 19gm whereas the mass of the transducer hoping to reproduce the sound was typically 200+ gm and thus was incapable of reproducing the overtones properly. What was 19 gm, I wondered? Reading his patent application, I see he is referring to the mass of the bass string(!!!) on the bass guitar. Really??

The notion that apparently was the core of the idea that was considered patentable seemed to be that the (moving) mass of the transducer should approximate the mass of the sound producing part of the instrument which is intended to be reproduced by the speaker system. If this is explored a little you come quickly to imponderables—like what should the moving mass be if attempting to reproduce the sound of an oboe—the weight of the reed? How about a flute? The weight of the air in the bore?

I can't tell whether the patent was granted or not, but if it was I am stunned, and my estimation of the discernment of the patent review board has slipped dramatically. Do I read the 'Brief summary of the invention' correctly in that the claim is that an array of very light moving mass transducers can reproduce overtones better than fewer heavier moving mass transducers? This is news? This is patentable???

This is nonsense.

See for yourselves:
http://www.google.com/patents/US9247339

Chicken Man · « **Reply #11 on:** 22 Oct 2016, 02:21 am »

Electro-mechanical transducers can only follow the 'average' level of an electrical waveform anyway so perfect reproduction of the source's peak levels is not possible.

Our ears also cannot follow the 'peaks' in a source's waveform, it is just all averaged out, and that's what we live with.

You are right Russell, it's pure nonsense.

C.M

Russell Dawkins · « **Reply #12 on:** 22 Oct 2016, 05:57 am »

I'm not arguing that the weight of the moving element in the transducer has no relevance—all other factors being equal, lighter is always better. What I am arguing is that this is not news and should not be part of any patent. However, the implied relationship between the weight of the moving element in the transducer and the weight of the object producing the sound is specious at best and that, to me, is nonsense—unless, as I say, I am misinterpreting the text in the 'Brief summary of the invention' in the patent application.

JohnR · « **Reply #13 on:** 22 Oct 2016, 08:38 am »

Its been a few days since I read the patent but I didn't really get it. For one thing, surely electrostatics and planar magnetics are "prior art"? For another, I don't see how the moving mass on its own is intrinsically relevant. Finally, the connection of transducer moving mass to the instruments that were originally recorded seems completely spurious.

fidobite · « **Reply #14 on:** 2 Dec 2016, 04:20 pm »

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.

- Trace

Folsom · « **Reply #15 on:** 2 Dec 2016, 05:32 pm »

Quote from: Russell Dawkins on 20 Oct 2016, 06:46 am

However, I detect loose techno babble of a kind I find objectionable in the descriptions of the various design principles on his website. I puzzled, for example over his mentioning that the mass of the source of the 41Hz tone from a bass guitar was 19gm whereas the mass of the transducer hoping to reproduce the sound was typically 200+ gm and thus was incapable of reproducing the overtones properly. What was 19 gm, I wondered? Reading his patent application, I see he is referring to the mass of the bass string(!!!) on the bass guitar. Really??

Wow... If that were true then all guitar/bass-guitar amps are absolute blasphemy too. Only acoustic is permissible.

DaveC113 · « **Reply #16 on:** 2 Dec 2016, 05:43 pm »

This is going to produce a cardioid-shaped bass response: https://www.google.com/search?q=cardioid&ie=utf-8&oe=utf-8

It's not a new concept and most recently the Kii Three speakers also employ a rear-firing bass driver that is meant to cancel instead of add, so it also produces a cardioid-shaped bass response.

IMO, it's an overly-complicated solution to a non-existent problem. It's not like cardioid bass is going to eliminate bass nodes under the Schroder frequency...

DaveC113 · « **Reply #17 on:** 2 Dec 2016, 05:44 pm »

Quote from: Folsom on 2 Dec 2016, 05:32 pm

Wow... If that were true then all guitar/bass-guitar amps are absolute blasphemy too. Only acoustic is permissible.

Lol, yeah... the concept is more than a bit ridiculous.

Tyson · « **Reply #18 on:** 2 Dec 2016, 06:01 pm »

I don't see why more manufacturers don't use the Servo OB solution that Danny and Rhythmik offer. It's a simple/easy solution that gives tons of bass slam while keeping OB wave propagation. Going from an OB upper section to any kind of sealed or boxed bass solution just makes no sense to me.

Folsom · « **Reply #19 on:** 2 Dec 2016, 07:04 pm »

Quote from: Tyson on 2 Dec 2016, 06:01 pm

I don't see why more manufacturers don't use the Servo OB solution that Danny and Rhythmik offer. It's a simple/easy solution that gives tons of bass slam while keeping OB wave propagation. Going from an OB upper section to any kind of sealed or boxed bass solution just makes no sense to me.

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