Tekton Design Enzo XL loudspeaker Measurements

Sidebar 3: Measurements

I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Tekton Enzo XL's frequency response in the farfield; and an Earthworks QTC-40, with its small, ¼"-diameter capsule, for the nearfield responses.

The Enxzo XL's specified sensitivity is an extraordinary 96.5dB/W/m; my estimated value was 90.6dB(B)/2.83V/m, which is much lower but still significantly and usefully higher than the average of all the speakers I have measured, which is between 87 and 88dB(B). Other than a small region in the mid-treble, the Tekton speaker's impedance magnitude (fig.1, solid trace) remains above 6 ohms at all frequencies, and the electrical phase angle (dotted trace) reaches extreme values only when the magnitude is high. The Enzo XL is therefore well suited for use with low-powered tube amplifiers.

Fig.1 Tekton Enzo XL, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

Some small wrinkles in the impedance traces suggest the presence of panel resonances in the large cabinet, which did indeed sound lively when subjected to the traditional knuckle-rap test. A more scientific version of that test is to excite the enclosure by feeding the speaker high-level MLS (Maximum-Length Sequence) noise, and plot a cumulative spectral-decay or waterfall graph from the output of an accelerometer fastened to one of the panels (footnote 1). Doing so, I found several high-level resonant modes on all cabinet surfaces, with one at 301Hz the strongest on the sidewalls level with the bottommost tweeter (fig.2) and on the rear panel. Another mode, at 262Hz, was strongest on the top panel, while a mode at 414Hz dominated on the bottom half of the side panels. All of these modes are of high Quality Factor (Q), so may measure worse than they sound. Also, the Enzo's high sensitivity will work against these resonances being as fully excited as they are in my measurements. It's appropriate to note that HR didn't comment on any coloration or midrange congestion that could be laid at the feet of this measured behavior.

Fig.2 Tekton Enzo XL, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of side panel level with bottom tweeter (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

The saddle centered just above 30Hz in the impedance-magnitude trace (fig.1, solid) suggests that this is the tuning frequency of the twin large, 2"-diameter ports on the Enzo's front baffle. As expected, therefore, I found that the minimum-motion notch in the woofers' combined output (fig.3, blue trace) occurred at 31Hz, the frequency at which the back pressure from the port resonance holds the cones stationary. The combined output of the ports peaks between 20 and 60Hz, confirming HR's finding that this speaker offers excellent bass extension. Though I've shown the combined outputs of the woofers and ports, each behaved slightly differently, the lower woofer having a double notch in its low-frequency response, and the upper port a much lower response peak at 230Hz.

Fig.3 Tekton Enzo XL, anechoic response on central tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with nearfield responses of woofer (blue), port (red), and their complex sum (black), respectively plotted below 300Hz, 1kHz, 300Hz.

The complex sum of the woofer and port responses, which takes into account acoustic phase, is shown as the black trace below 300Hz in fig.3. Although HR felt the Enzo XL had a low-Q bass alignment, the apparent peak in the midbass, which is primarily due to the nearfield measurement technique, does suggest that the Q is a little higher than he conjectured.

Higher in frequency in fig.3, the black trace shows the Enzo XL's farfield response on the middle-tweeter axis, averaged across a 30° horizontal window. Overall, the balance on this axis is impressively even, though a slight lack of energy in the upper midrange and low treble probably correlates with the lower-than-specification measured sensitivity. It might well also correlate with HR's finding that the Tekton's "overall sound leaned a tiny bit more toward the Puritan, the restrained, and the businesslike than I prefer."

With the Enzo XL's larger-than-usual woofers, whose radiation pattern will narrow at the top of their passband, it was not surprising to find a slight off-axis flare in the tweeters' passband (fig.4). But this will also be due to the lack of energy on axis mentioned earlier filling in somewhat to the speaker's sides. It might, therefore, be worth experimenting with toe-in to get the most neutral treble balance. However, with that wide baffle, the tweeters' radiation pattern narrows considerably above the cursor position in this graph, 4.35kHz, and this is not compensated for by any rise in the top-octave response. Though this will not be a problem in small rooms such as HR's, the Enzo XL might sound a bit too mellow in large or heavily damped rooms. In the vertical plane (fig.5), a suckout develops more than 5° above the middle-tweeter axis. This will not be a problem, given the fact that that axis is 42" above the floor. The suckout in the on-axis response around 2kHz does tend to fill in below this axis, and to my surprise—given the vertical array of three tweeters—the Tekton's vertical dispersion in the top octave is wide.

Fig.4 Tekton Enzo XL, lateral response family at 50", normalized to response on central tweeter axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis.

Fig.5 Tekton Enzo XL, vertical response family at 50", normalized to response on central tweeter axis, from back to front: differences in response 15–5° above axis, reference response, differences in response 5–10° below axis.

The Enzo XL's step response (fig.6) indicates that all five drive-units are connected in positive acoustic polarity, with the arrival of the tweeters leading that of the woofers by about 400µs. However, the decay of the tweeters' step smoothly blends with the start of the woofers' step, implying good crossover design. There are some undulations in the decay of the woofers' step, which the cumulative spectral-decay plot (fig.7) shows are associated with a high-Q resonance at 1864Hz. I would have thought that this resonance, perhaps due to a problem with the termination of the woofer cones' surrounds, would add hardness to the sound. HR didn't comment on an audible problem in the presence region, but did say that the Tektons "got not only the tone, the attack, and the decay, but the plucked-string pulling-up emphasis of the bass player's art"—just the kind of tonal emphasis I would expect from such a low-treble resonance. (Bass guitarists often use a presence-region boost to emphasize the "ping" in their instruments' sound—at least, I do.)

Fig.6 Tekton Enzo XL, step response on central tweeter axis at 50" (5ms time window, 30kHz bandwidth).

Fig.7 Tekton Enzo XL, cumulative spectral-decay plot on central tweeter axis at 50" (0.15ms risetime).

Overall, the Tekton Enzo XL measured much better than I was expecting, given its idiosyncratic design: three tweeters in a vertical array, two large-diameter, paper-cone woofers, and that lively enclosure. Its combination of high sensitivity and extended low frequencies is rare in speakers in this price class, and, other than that resonance just below 2kHz, seems to have been achieved with little compromise elsewhere.—John Atkinson

Footnote 1: See "The Sound of Surprise."
Tekton Design LLC
1488 W. 400 S.
Orem, UT 84058-5139
(801) 836-0764

BradleyP's picture

It's good to see this company (this man?) get serious attention. Tekton owners--tubophiles, mainly--rave about their speakers and wouldn't be parted from them. Their $1k floorstanders seem to set a standard in the category, as the Enzo is now implied to do with its enviable Class B recommendation. I've never heard Tektons but am eager to do so.

Jacob Nielsen's picture

This speaker may be a fun listen, but it has fundamental issues: The cumulative spectral decay plot hints that the woofers output extend into breakup region. Sacrificing two of the tweeters for a dedicated midrange would have resulted in a conventional (boring?) 3-way performing better at the same parts cost.

tektondesign's picture

Good loudspeaker design at this price point ($1050 each) is an exercise in trade-offs and I personally don't see any of this as a deal breaker. One could always go with the smaller original Enzo (8" diameter) and sidestep the issue entirely.

Jacob Nielsen's picture

So a dedicated midrange was traded off for two extra tweeters? And an extra woofer? These are not cheap tweeters, and they are good tweeters, but they are not midrange drivers. Having 3 units to distribute the burden does help some, but then the resonant frequency should have been lower (units must have bigger rear chambers) Two woofers is a way to lower distortion while trying to deliver midrange. The drawback is twice the box volume - and twice the parts cost. A conventional 3-way could be made from similar parts (plus midrange unit) at around 2/3 material cost, smaller box, but still deeper bass, cleaner midrange, less vertical treble beaming. Why then was this conventional design not reviewed, why wasn't it built? Because it would look boring, right?

tektondesign's picture

Thanks. Not much in the world of loudspeaker design ever gets too "boring" for me. In my estimation the Enzo XL doesn't contain "drawback" attributes. There is more going on with this model/design than you are perceiving. I see it as forward thinking innovation that sounds great and delivers something truly special at a $1050 price point.

Jacob Nielsen's picture

...has been cleverly dealt with, it seems, by having only one of the units handling the top frequencies. My point is just this: a wwttt is a bit of a gimmick.

tektondesign's picture

I invite you to review the past successes of our company. I would be saddened to ever be perceived as a company that produces "gimmick" products.

Jacob Nielsen's picture

...has been cleverly dealt with, it seems, by having only one of the units handling the top frequencies. My point is just this: a wwttt is a bit of a gimmick.

tektondesign's picture

I invite you to review the past successes of our company. I would be saddened to ever be perceived as a company that produces "gimmick" products.

Allen Fant's picture

Excellent review, as always, HR. What happened to your friend Ryochi?
I will add these speakers to my must-demo list. Reading over your review, you mentioned about hearing deep Bass- this is accomplished by drivers at least 10" in diameter. It is wonderful to see/read about a manufacturer placing double 10" drivers per cabinate. This practice makes all of the difference.

corrective_unconscious's picture

Says a lot. That's an odd choice to mate a 10" driver right to a 1" one.

Putting three 1" drivers vertically like that is also odd, but it's less unusual to find a speaker which demands listening on a limited vertical axis.

They're affordable and offer high efficiency relative to other non mass market floorstanders, but I'm skeptical they'd really compete with the Vandie 1C or the similarly priced JBL or Polk floorstanders.

Audio Fyle's picture

Not sure about the Vandersteens. Been many a year since I heard any. But trust me, these will leave the comparable JBL's in the dust.

Audio Fyle's picture

Having heard the Enzo's big brother the Pendragon, I can honestly say that I have never heard a speaker more dynamic. Shame it was at a show, so I really couldn't give them the audition they deserved. But I was amazed at their musicality and power.

By the way, I find it interesting that you chose Mahavishnu for auditioning material. One of my go to discs for speaker testing is 'Visions Of An Inner Mounting Apocalypse'...an excellent Mahavishnu tribute CD featuring some of modern fusion's greatest guitar talent. Smokin' disc and the dynamics really give speakers a working over.

klosterman's picture

Nice review.

tektondesign's picture

An ad hominem attack – how sad. Truly discerning if Herb’s right or wrong requires some real thought and effort.

klosterman's picture


tektondesign's picture

The word is discerning. As in discern... to perceive or recognize.

dbs5150's picture

I have some insight on these speakers. I went to a high-end A/V company and auditioned two sets of speakers. First the Vaunted Golden Ear Triton 1. Sterile, mechanical sounding and when I asked the salesman to put on "Brain Damage" from "Dark Side of The Moon" it was a disaster. The ribbon tweeter could not handle the music, it was nothing but a horrible failure, it turned to spaghetti. The salesman rushed into the listening room to turn the the amp down. He the admitted "well his music IS very dynamic."$5000 for that? The low end Martin Logans were not much better.

So on to Tekton. Yes I rolled the dice on not hearing the speakers, and I am glad I did. The first cd I put on was "Dark Side of The Moon". The same friend that was with me(no clue about hi-end audio) at the hi/end demo busted out laughing at how great the speakers sounded. She could not believe it, even SHE knew these were much, much, better than what we heard AND it was with a cheap Yamaha receiver. Not the $50 thousand dollar amp set-up at the a/v store.

This is a "Real world" experience from a audiophile and a lay person.

Listen to them BEFORE you give your "theory" opinion.

iListen's picture

which ML's are you talking about please?
I am looking high an low for a speaker that I find satisfying for around $2k
I found a local place where I can go listen to the ML motion 40's.

I also want speakers I can drive without needing a $5000 amp. Considering something like NAD 375, or Nova 125SE, etc etc, $1500-ish range

dbs5150's picture

And "Brain Damage" was handled by these speakers absolutely perfect. These speakers handle everything, wait until you hear classical music on them. WOW.

sharethemusic's picture

let me just say this.every single person,without fail,who has entered my music room states the following:"best speaker,andy..i have ever heard in my life".....no over analytical approach,no measurements,no words..the PROOF IS IN THE LISTENING. i owned altec lansings as a kid playing thru mcintosh..than i owned dalquists dq20's thru college and beyond...i have listened to many home audio systems with 25k and up speakers. the enzo xl is BETTER than any i have heard. i might add i have erics lore reference in my living room. there sooooooo amazing as well. forget best value.best speaker maker in US period. andy rothman sharethemusic@aol.com

reubenr's picture

Regrettably, this is my first post, so it will be longer than it need have been. Much of the speaker commentary is not very helpful, since they seem to reflects biases that are ungrounded for the most part or are so esoteric, they beg for irrelevance. These speakers seem to get some very positive reviews with only minor negative commentary, the latter having mostly very little to do with how they sound, but more like a nit picking engineering feud that might mean something, but to those who are trying to make a purchase, it means little or nothing, mostly nothing. The last post by "1st Person" seems like a very relevant post, since he has heard and lived with the speakers. There are other very relevant posts, as well. I guess the only real question that I would have is the conflict between the stated SPL and the tested, which seems to present quite a variance. Either the speakers are easy to drive with a tube amp like the Cronus Magnum II or they are borderline or worse. It makes a difference to get the facts straight. Why there is such a big difference seems very confusing, but, like I said, this is my first post, so what do I know. I've been listening to great music for a very long time and have never really wondered about the speaker's ability to deliver the goods, but now that I have a few bucks to throw around, why not try to get the best. These sound like they would sound very good in a small to medium sized room for a wide variety of music with the emphasis on musicality rather than loudness. No?

Rust's picture


Thank you for the review. Prior to your review I had never heard of Tekton Designs. I had been looking for a new set of speakers for a couple of years as my ancient and much loved primary speakers could no longer be repaired as I had already bought the last mid-driver in existence. I had listened to a LOT of potential replacements in the $10k and under range and was in general disappointed. So I called Tekton, spoke to Eric, and based on that conversation ordered the larger Pendragons.

Once received, I tossed the packing material the next day, they were NOT going back. Like my old Fender Tweed and Washburn T-Bird Deluxe, they are keepers. Yeah, the driver layout is different, they don't weigh a ton, they aren't made of exotic unobtanium. They just work on everything from Hillary Hahn to Led Zeppelin. You'd have to spend a lot more money to find a speaker that had better overall performance. After a year my opinion is unchanged.

Once again, thank you Herb

Sleepr0's picture

You know, it amazes me how self-declared “audiophiles” and “engineers” have opinions on the sound or veracity of a loudspeaker’s design without having heard it. I mean here they are, facing a positive review from someone who does that sort of thing for a living and without having heard the product themselves, panning it. This is how audiophilia gets a bad name.

I am currently auditioning the Lore a Reference and, to be honest, still trying to get a handle on it 4 days on it. When I try to listen “to the speaker” I get frustrated, probably because each musical piece sounds different from the other, unlike any speaker I’ve ever owned before. By that definition, these are the most neutral speaker I’ve ever heard. They are not kind to poor recordings, but sing out on excellent ones - not unlike the Snells I heard many years ago. Thing is, I did not like the Snells then because they were really unforgiving toward bad sources and the first thing I heard on them was just that. I never gave them another chance because the Klipschorns in the next room were so amazing and flattering to everything played through them. I have since recognized that that was because the Khorns had a sound of their own; a good sound, but theirs nonetheless.

I wrote Eric a short note about the Lores and mentioned that I was still “breaking in my ears”. And that that’s just it. These speakers have truly full range with absolutely no glaring faults. The question is, is this what I want? I don’t know, but I’m not passing judgement until I’m done listening to them and asking myself if they are right for me. Every commenter here should do the same, IMHO.

I will say one thing - there is absolutely nothing “wrong” with this design. Eric should be proud of what he’s done with them. If I do return them, it will be because I am not ready for “the truth” - not because they are bad speakers. I won’t be updating this post because my opinion should not matter to you. I suggest that you take a chance and try them yourself. Yeah, it’s a risk because you will be out return shipping AND a restocking fee, but the audition is worth that cost at least and you may learn something - about yourself - in the process.