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Monacor Triax 15 - quasi-coax with mid in a magic eraser "enclosure"

jhaider

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*For those unfamiliar with American cleaning supplies, the foam material used here is commonly sold in the US under the "magic eraser" brand name.

There’s a really unusual design in the current issue of Klang+Ton called the Monacor Triax 15. Basically it looks "inspired by" ME Geithain but with a less interesting bass cabinet - there is a 6" mid and an AMT tweeter on a bridge over a 15" woofer, but the woofer is standard bass reflex cabinet rather than a cardioid. Woofer-to-mid crossover is a bit under 500Hz. It looks like the writeup on this speaker (in German) is free at the link below (I did not redline it against the K+T article but it looks substantially the same):


The really interesting part to me is the mid “enclosure” - there is none! All they did was plug the midrange's pole piece with a felt furniture foot and wrap the midrange basket in a magic eraser* that seems to be secured with the midrange's speaker wire! (The mid-tweet baffle itself seems to be some sort of laminated construction, with a 10mm board and a 6mm board, along with a carpet underlayment-type material.)

monacor-triax-15-lautsprecherbausaetze-75818.jpg


My (bad) translation of the relevant part: The holes in the basket of the midrange are covered with Basotec, and its polepiece is sealed with a felt glider from the hardware store. The mid doesn’t have to play bass, so [the foam and felt] largely acoustically seal it."

The FR - fairly described in the article as "not the prettiest in the world" - does not really show any clear effects from the midrange "chamber" from what I can see, but obviously that's just a sweep and not IM. This might be a question for @René - Acculution.com!
 

Zvu

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Here's the original thread:

 

thewas

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Basically it looks "inspired by" ME Geithain but with a less interesting bass cabinet
The really interesting part to me is the mid “enclosure” - there is none! All they did was plug the midrange's pole piece with a felt furniture foot and wrap the midrange basket in a magic eraser* that seems to be secured with the midrange's speaker wire
By the way a similar mid "enclosure" is also used on the cardioid 3 and 4 way MEGs.
 

kemmler3D

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Hmm, neither the on or off-axis measurements seem like this design really panned out so well. It's interesting but is the idea to absorb the backwave from the mids with just a bit of basotect / melamine? I feel doubtful that that would work. Press a piece of basotect over your ear, you will still be able to hear things. It's good for absorption but not sealing / blocking.
 

mhardy6647

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I mean -- folks were doing this (more than) 70 years ago -- although there was no Magic Eraser stuff to use for damping or backwave control or whatever.
1946 Jensen:
1705357617845.jpeg


It's not a great way to make a coax, but it's a cheap way to make one.
 
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jhaider

jhaider

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Not an open with foam delayed mid for cardioid pattern though like at Geithain.
Right, I wasn't clear. More like a more rigorously modeled and production engineered variant of the midrange damping used in the Monacor speaker kit.
 

Haskil

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I just noticed the new big KEF in-ceiling triax uses the same approach as well.

index.php
This type of tri-axial speaker, new to Kef, has been a great specialty of the French company Cabasse for a good thirty years. It is used on their two-way in his bi axial version and three-way models in four way. Including the model that crowns their ranges: the Sphere. And before The Atlantis...

Cabasse was an objectivist manufacturer...

“The speaker is the “The speaker is the opposite of an instrument. It must be transparent, neutral, make no sound of its own but be able to reproduce them all; without adding, subtracting or distorting anything. This is why we always compare our speakers to direct music"
Georges Cabasse opposite of an instrument. It must be transparent, neutral, make no sound of its own but be able to reproduce them all; without adding, subtracting or distorting anything. This is why we always compare our speakers to direct music"
Georges Cabasse

He had invested in what was the largest anechoic chamber in Europe, published complete measurements, free brochures advising choices in terms of amplification by giving charts in terms of necessary power as well as for the diameter of the cables depending on the length, the impedance of the speakers, organized comparisons of direct sound reproduced at the Paris International Sound Festival (an orchestra played live... stopped and the same music continued on the brand's speakers ), railed against HP cables and therefore provided a standard cable with its speakers: in the midst of a subjective audiophile wave, this manufacturer was going against the tide... He admitted to having been forced to stop providing this cable with his speakers due to from the network of resellers who did not appreciate...
I don't think Cabasse was distributed visibly in the United States, but in Germany and France the brand was very, very famous... And the second-hand market is still alive... And given the exceptional quality manufacturing, models over 50 years old are still going strong! The brand repaired all the loudspeakers it had manufactured for a very long time... decades later... But the founder was, he said, incapable of producing good speakers economically and the 5.1 caused him a lot of problems. wrong... But hey, the brand survived and remains a flagship of electroacoustics... and its idea of a true triaxial was innovative. It's very good that Kef is getting into it








 

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