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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
erik_squires OP
5,268 posts
 
teajay -

* moot * :)

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

Erik
seanheis1
359 posts
 
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
1,333 posts
 
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. 
erik_squires OP
5,268 posts
 
@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. :) 
erik_squires OP
5,268 posts
 
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 
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