Tekton DI Monitors


Finally got to see the measurements for the Double Impact monitors. I’m a little disappointed.

https://www.stereophile.com/content/tekton-design-impact-monitor-loudspeaker-measurements

This woofer - tweeter - woofer configuration is similar to the style named after the esteemed Joseph D’Appolito. Done well this configuration functions like a single large woofer in terms of dispersion. Less floor and ceiling bounce yield better detail at the listening position. 

Interestingly, the Audiogon craze of criticizing the tweeter array for possible comb filtering is not what I’m sad about. In fact the array appears to be the least of the issues. Look at figure 4. The horizontal plots are superbly clean. Any comb filtering from the tweeter array would be displayed here, and it’s not. Those critics going nuts about the array’s poor performance can apologize for their uninformed criticism right now.

The problem is really the vertical response. It is terrible. Here we do have evidence of comb filtering! See the plot closest to the viewer in figure 5? See the regularly occurring hills and valleys completely absent from figure 4? That my friends is comb filtering. However it’s not coming from the tweeter array, but from the two widely placed woofers. There’s also a great deal of hash above 5kHz on this same plot. This makes me so very very sad.

Part of this is fixable. As Dr. D’Appolito discovered, the designer should have used a higher order crossover slope, which would have taken care of the hash above 5 kHz. However the comb filtering below this is not easily remedied. The issue has to do with how far away the two woofers are from each other. They are so far, and cut in so high that they can’t help but interfere with each other and this woofer to woofer distance is ultimately controlled by the size of the tweeter array.

Should you buy this speaker? I think you should listen to it. See how it sounds to you as you move around your listening space. If you find yourself enamored of the mid-treble resolution and detail, I would encourage you to listen to other Tekton designs that don’t attempt a D’Appolito design, because I'm afraid that the main benefit of this type of design, narrow mid-woofer dispersion, is lost.  A simpler 2-way would avoid these issues and be as good at detail and resolution 
erik_squires
To address seanhies1 "pet peeve",

Here's the speakers that have been in the same system for review that the the DI Monitors were compared to: Role Audio Enterprise Speaker 4K, Lawrence Audio Violin SE Speaker $8,500, Lawrence Audio Mandolin $5,500, NSMT Super PSM Monitor Speaker 5K.  These are all wonderful music makers that I gave high ratings to and enjoyed having them in my home.  However, the much less expensive DI Monitor was at least there equal and out preformed them on certain sonic parameters.

erik_squires,

Part of the magic of both the DI Monitor and the DI's is that the circle array with the tweeter in the middle functions as a single point co-axial driver that virtually weights nothing so it presents with horn like dynamics and yet has the speed/transparency of a planar design.  So, in my experience with this speaker you get all the benefits with out short-comings.  I hear no muddling of the mid-range band and the upper bass foundation, along with taut powerful lower bass extension, is excellent.


roberjerman,
I'm sure you speakers are better than mine and I'm glad you are able to fully enjoy them while walking about the room.
Me, I'd never seriously listen to ANY speaker that way--yours included.


Based on the impedance charts, I'm guessing the woofers cross over at around 1kHz when (based on spacing) they should have been crossed around 300 Hz.  Alternatively, the designer could have done an (array) - WW design, eliminating the comb filtering altogether and providing similar output. 

In case it's not clear, one reason I wanted to talk about this design and measurements is that it clearly illustrates comb filtering while at the same time proving the tweeter array doesn't have any. It's pretty ironic to me. :) 

Best,

Erik 
@teajay - On the other hand the woofer to array crossover seems rather high, around 1-2 kHz, so we can’t call the outer ring mid-woofers either.

Point is, why bother with a W - (something) - W array if you are not going to get the benefits?

Yeah, this is one major reason I throw Stereophile reviews in the trash. Bad rooms they refuse to do anything about, or failure to listen to manufacturer's requirements before auditioning. Their measurements are credible though, so worth looking at, especially when they completely dispute their review. :) 
By the way guys,

Technically, the DI Monitor is not a D'Appolitos design because it is a three way design, not a two way design.  The smaller transducers sonicly function as a single point two way coaxial speaker, hence it's a three way design.  In a true D'Appolitos approach you have MW/T/MW drivers that are always a two design.

The reference UIF's are a true D'Appolitos were the double circle array of small transducers are the MW "drivers" flanking the tweeter between the two arrays.  

I nick named the DI Monitors Jr DI's because in a smaller acoustic space they are very similar to their larger siblings in performance.  What surprises a lot of my listeners is the powerful bass extension and overall macro-dynamics of this stand mounted speaker.  It completely disappears like all reference level stand mount monitors, but presents over all as if its a full size floor-stander.  Unlike Herb, I had no problem with over loading my room with bass, and did not have any reason to stuff the rear ports with socks. I think his review says more about the limitations of his room regarding bass response, then any short-comings in the bass response of the DI Monitor. 
Terry, sorry but this is a reviewer pet peeve of mine. Mentioning that a speaker outperforms speakers costing more than 3 to 4 times its price....but then failing to name those mystery speakers. 

In the review, you make a comparison to the pint sized KEF LS50, a speaker that costs $500 less and the B&W 705S2, a speaker that costs $500 more...
teajay -

* moot * :)

And thank you for your informed listening experience! It sounds like that tweeter array is behaving as expected for you. 

Erik
@corelli - 

It really depends on the buyer. I often have music playing in my home regardless of what I'm doing, so having a pleasant off-axis experience in both planes is important for me. There's much that has been written that a lot of consumers really value a wide sweet spot. Magico and Revel designs specifically for this. The DI Monitors seem to have plenty of that. 

I'm just super disappointed in that these appear to be a failed D'Appolito design. Part of what you get with a D'Appolito is a tighter vertical dispersion down to the mid-bass, which these speakers do not have. 

They are aesthetically D'Appolitos without being functional D'Appolitos. Am I being too critical? 
I reviewed the Double Impact Monitor for hometheaterreview.com, gave them five stars out of five stars, bought the review pair to use in my smaller reviewing system and am delighted with their performance.  I have had speakers in for review in this system that cost more then 6K to 8K that were easily out performed by this 2K speaker.  I have had many listeners that are shocked at how beautiful the DI Monitor sounds even compared to the ULF's in my much more expensive reference system.

Frankly, when I'm listening to music I'm sitting down in front of my system, therefore, believe it's mute how the speaker sounds when I'm walking around in the room.  I'm always listening to music when I'm home, like now as I write this, as background pleasure, but that has nothing to do with serious listening to either of my systems.  So, who cares what any speaker sounds like when your walking around the room. 
Don't stand up! Seated listening only! I doubt that the DI's sound as good as my JSE Infinite Slope two-ways!
I noted the same issue.  But honestly, I never listen outside the sweet spot.  Even if I am outside that spot in the horizontal plane it totally destroys the sound stage/imaging for me with the DI's or any other speaker for that matter.  So for me it is a total non issue. 

For more mobile listeners, this will be a consideration.  I'll just never understand how this would be a priority for the vast majority of critical listeners however. 
Mr. Erik, wouldn’t the Ulfberht solve the issues you mention due to the much lower crossover point? 200hz vs 1000hz?