January 2010

Tekton Design OB4.5 And Subwoofer
A follow-up to my original reviews.
Review By Rick Becker 
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  "Stop the presses!", begged Eric Alexander of Tekton Design. He had forgotten to send me the high pass filters for the OB4.5 monitors to be used in conjunction with the Tekton subwoofer I had just reviewed. The filter, he claimed, would overcome my chief complaint about the combination — that it couldn’t play louder without causing the monitor to break up. The short story, of course, is the review was published and the monitor and sub were awarded a Blue Note Award for 2009. The combination had some limitations and some flaws, but for less than $2000, it was a category killer. The longer story, obviously, is this follow-up review. If I seem to have overlooked something here, revisit the review of the OB45 hybrid loudspeaker (click here) and S12 subwoofer (click here).

The filters arrived housed in an open box that was to be connected in line with the monitors, using an extra pair of speaker cables. Fortunately, I have a second set of JPS Labs Superconductor+ for reviewing bi-amplified or bi-wired loudspeakers. If the OB4.5 monitors are ordered with the subwoofer the filter can be built into the monitor for an additional $125 and a second set of speaker cables will not be needed. Some might question whether adding the filter works contrary to the benefit of having no crossover whatsoever with this full-range single driver design. The filter acts well away from the midrange, as does the variable crossover in the sub. In fact, this is a similar approach to the one used by Albert VonSchweikert in his Unifield 3 loudspeaker. The proof is in the listening and I found the music coming from the monitor to have even greater focus and transparency when the little 4.5” Fostex driver was not asked to cover the upper bass region.

The most beneficial effect for me was a greater sense of ease in listening. Without the filter, I had to be careful about not playing music loud enough to break up the full-range driver. I always gave it my best guess, but music is a complex signal. Occasionally a combination of notes and instruments might come along that would generate noticeable distortion. Not often, but it would happen once in a while. This has the effect of creating subconscious stress while listening. I wasn’t aware of this until the filters were installed, permitting the loudspeakers to play much louder than my normal comfort zone. The music was more relaxed and so was I.

Is Louder Better?
The open baffle designs of both the monitor and subwoofer have incredible focus and transparency as I noted in my original reviews. It gets even better with the filter in place. But such a high degree of focus and transparency leaves little room for flaws in the music or flaws in the reproduction system to hide. It also makes it less pleasurable for listening at high volume unless you’ve got a great system in a dedicated room, listening to good recordings. Even with the filter, you will not be able to play back music at concert levels. At least in my large room the little 4.5” driver couldn’t do it. But it plays at considerably higher volume than I care to listen to most of my recordings. Roy Orbison rocked with “Oh, Pretty Woman” from Black & White Night with the filter at 95dB without breaking up, whereas it was barely comfortable at only 87dB without it. BB King, along with Eric Clapton in Riding With The King, peaked at 98dB when he was shouting his “Three O’clock Blues” and sounded coarse, but undistorted. This is a substantial difference and a huge improvement, though still not ear-splitting concert levels.

The good news is you don’t need to blast your music to enjoy it with the Tektons. One reason I used to crank up the volume was an often futile effort to pick out details in the music or figure out obscured lyrics. Another reason was to simulate the experience of a live performance — to create the “you are there” experience. Those days are gone with these loudspeakers. The Tektons tell you without ambiguity what is on the recording. And the transparency and focus make it far easier to make the leap of faith that you are listening to live music rather than a recording. It may not sound like being at the edge of the stage, mere meters from a tower of speakers, but listening further back in the venue will undoubtedly prolong your sense of hearing — and you’ll miss nary a word or a note.

Louie, Louie
Those who really know will tell you the best way to figure out the lyrics of “Louie, Louie” are to play the 45rpm single at 33.33. For an analysis and historical perspective, check out this link. Being the curious type, I pulled out my well worn LP by the Kingsmen and gave it a try with the Tektons. I couldn’t verify the lyrics with certainty one way or another, but I’m here to tell you, if they had switched the mike on the kick drum with the vocal mike and EQ’d it properly, J. Edgar Hoover would have thrown the band in jail and the ACLU would have raised an uproar.

The Flaws?
My friend Tom Lathrop has heard the Tekton monitors in my rig and in his own where it temporarily displaced his Usher Tiny Dancers. He has also heard the monitors in combination with the subwoofers with the filters in place. He feels there is a slight coloration in the midrange that he picks up with some female vocal recordings with which he is very familiar. I don’t listen to much female vocal music, aside from Joni Mitchell and Melissa Etheridge, so it went unnoticed to my ears. Nonetheless, I respect his listening skill and feel obligated to mention it.

The other flaw, which I hinted at above, is that the speaker combination is so articulate that if you were not a big fan of CDs and the quality of digital sound, you may like CDs even less with the Tektons. Or perhaps you will be enticed to upgrade your digital front end — something that may be inevitable anyway with the blossoming of Blu-ray. The flip side of this coin is that if you love analog sound, the Tektons take it to the next level, coming across like a major upgrade of your cartridge, turntable and phono stage. Shortcomings in your analog front end may well be revealed, but with analog music, that revelation is a lot more palpable. Likewise, the Tektons will probably enhance your enjoyment of music if you are using older tube gear that comes across on the warm side.

With Filter Yet Without Sub
The inevitable question arises, if one could only afford the monitor alone, should they be purchased with or without the filter? I’ve detailed the differences as I’ve added first the subwoofer and then the filter. To get a better perspective on this issue, I deconstructed the ensemble in two steps. First, I disconnected the subwoofers, not by simply turning them off, but by removing the interconnects from the preamplifier and also unplugging the power cords at the power conditioner. The importance of this complete disconnect was driven home to me in a conversation with Ken Stevens of Convergent Audio Technology. The line stage and the dedicated ac line still “see” the subwoofer if it is merely turned off. Disconnecting the power cord at the wall or power conditioner and the interconnects at the line stage take the subwoofer completely out of the circuit and the sonic picture. Of course Ken had a much more technical explanation.

The audible consequence of this was to remove the mid and lower bass, of course. But the loss was not as great as I expected it might be. Subtle low frequency room tone was gone, but much of the music on my compilation CD had little room tone, being processed studio recording. Nor was the absence of bass as obvious as I thought is would be. Most of the music lies in the midrange as we are told over and over. If I knew bass notes were present in a certain piece, I noticed their absence, but I didn’t necessarily miss them being there. And with unfamiliar works, you don’t miss what you don’t know is supposed to be there. Notes that were on the cusp of the cut-off (70 to 80 Hz) were merely distant in the mix. What was readily noticed and greatly appreciated was the top to bottom continuity of outstanding focus, phase coherence and point source imaging, as well as all the other great features I’ve mentioned before. So often small loudspeakers strive to extend the frequency range of the bass and it comes across with a prominent bump in the upper bass and/or the bass gets more out of focus the deeper it goes. Not so with the OB4.5 with filters. It goes top to bottom with outstanding focus and transparency. But the bottom is not as deep as the OB4.5 without filters. And this was the next step.

The OB4.5 Without Filters
Removing the stand-alone filters and the additional set of speaker cables brought me back to the original form of the first review. The bass definitely went a lot deeper, but in doing so it became a lot less focused than the midrange. In fact, the midrange and treble both lost some focus and transparency. This was the flip side of the benefits of adding the subwoofer about which I spoke in my second review. If you upgrade from a lesser loudspeaker, of which there are legion, to the OB4.5 you will be as ecstatic about this speaker as I was in my first review. But downsizing from the full-tilt boogie with the filter and subwoofer combination, the unfiltered stand alone OB4.5 seems a little more ordinary and the looser bass becomes less acceptable.

You can’t have everything in a small package. The OB4.5 with the built-in filter is a great compromise if you can anticipate adding the subwoofers sometime in the future. But if you listen in a small room and you wish to keep the overall expenditure to a minimum with no expectation of upgrading the loudspeakers, the standard OB4.5 is hard to beat. In downsizing the speaker to just the monitor the most significant observation may be the increase in my toe tapping. While the fuzzier bass is less accurate, it hits the emotional side of the brain, whereas the more accurate combination of subwoofer, filter and monitor appeal to the more cognitive lobes. But cognitive as it may be, it is a surprisingly easy leap to imagine you are listening to the live event.

Stacked
One of my problems with the addition of the second subwoofer was my lack of a sufficiently long interconnect and power cord to allow stacking the left channel monitor on top of the left subwoofer. My friend Tom Lathrop cobbled up a long interconnect from some Canare GS-6 guitar amplifier cable. Together with a cheap, but longer power cable and some Sound Dead Steel IsoFeet and Boston Audio Design TunePlates I was able to stack the monitors on top of the subwoofers. Without doing micro-measurements it sounded pretty good in spite of the fact that I had to pull the left speaker a foot closer to the center line of the original position. This also raised the height of the Fostex driver closer to ear level. The biggest improvement was the effect it had on tidying up the listening room and giving me better access to my component rack. Acoustically, there is an optimum position, but the speakers sound so great that I haven’t mustered enough momentum to find it. Beside that, we are about to cut down a Noble Fir and graft it to the floor of the listening room for Christmas.

Aesthetically, stacking the OB4.5 on the Subwoofer creates sort of a garage band look in the black satin finish. Optional finishes and veneers are available for both pieces, and some work needs to be done to establish repeatable positioning relative to each other. It is all do-able if you and the significant others who share your abode have an open and refined sense of design. If you’re talking about your personal Man-Cave, satin black is sufficient.

SPL Chart
I charted the OB4.5 with the filter in place and then charted the combination of the Subwoofer and monitor together. They overlapped perfectly in the lower midrange. Surprisingly, with just the monitor and filter playing, the upper bass measured stronger than when the subwoofer was added to the monitor. Below 100 Hz the monitor rolls off precipitously. I had the crossover on the subwoofers set somewhere around 80 Hz. Note the mid-bass hump in my previous review without the filter in place has been virtually eliminated. The area shaded in red represents the contribution of the subwoofer. While the addition of the subwoofer extends the bass significantly, the chart does not reveal how fast, tight and true the notes sounded. Have I heard better subs? Precious few, but nowhere near this price range and size. Keep in mind this SPL graph is an in-room measurement with a Radio Shack analog meter located at the listening position, not an on-axis measurement.

Summary
A lot of people will not be able to get beyond the look of this loudspeaker ensemble. The construction is basic; the parts are few and inexpensive. On the other hand, the engineering design is Patent Pending, the construction is very competent and with the filters in the monitors most people would consider the sound reference quality. While it is not perfect; it still will not play at ear shattering volume, though it plays significantly louder with the addition of the filters. But it is by far the best full-range loudspeaker I’ve ever heard under $2000. If I close my eyes, it is not difficult to imagine I am listening to a $20,000 pair of speaker. It is that good.

Specifications
OB4.5
Type: Full-range single-driver hybrid loudspeaker
Frequency Response: 45 Hz to 20 kHz
Drivers: Two 4.5-inch Fostex 127E
True full-range-no crossover
Sensitivity: 92dB/W/m 
Impedance: 4 Ohms
Weight: 21 lbs
Dimensions: 22 x 13.25 x 12 (HxWxD in inches)
Custom finishes available
Price: $550, optional grills adds $45/pair
Tweeter addition adds $50/pair

Subwoofer
Type: Subwoofer with 300-watt amplification
Drivers: Two 12-inch transducers (Danish Sound Technology)
Frequency Response: 27 Hz to 120 Hz (20Hz in-room)
Sensitivity: 92dB/W/m
Power: 300 watt RMS, BASH300S subwoofer amplifier
Adjustments: Variable frequency X-over, LFE input, phase, high level inputs
Weight: 52 lbs
Dimensions: 18 x 14 x 19 (HxWxD in inches)
Grille included
Custom finishes available
Price: $650

Company Information
Tekton Design LLC
272 South Ridgecrest Drive
Orem, Utah 84058

Voice: (801) 836-0764
E-mail: tekton_design@yahoo.com
Website: www.tektondesign.com