The Contendo II is here, my quest is ...over?

Aries Cerat

Industry Expert
May 30, 2015
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Contendo2-images13.jpg


Establishing the company 12 years back, with a sole purpose of creating the Contendo MK1, what is IMVHO the best speaker out there. In Feb 2010, I had no idea how big, complicated and elaborate this project would be.

From the creation and design of our electronics, for the task of helping us develop our speaker, to the spin-off speakers that came out (using tech from the main speaker project), it was a quite a ride.

The electronics that were developed as lab tools for the speaker design, were the foundation of what is now our electronics series, are now what become our main design and manufacturing business.

It was time to finish the speaker project
The Contendo II is out. First pair is already in it's shipping crates, a total of 20 crates, totalling 3 tones, is soon on it's way, while we are preparing for another two pairs.

More technical stuff to follow.

A number of people heard the prototypes in our space from the four corners of the globe.

I just feel lucky i am enjoying the prototype as a daily speaker in the shop, even as background music :)

Cheers
Stavros

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LL21

Well-Known Member
Dec 26, 2010
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Look forward to reading more. Congratulations on your efforts to push the performance barrier with your company once again. I recall that the original Contendo had a sub tower almost the size of a big Wilson speaker...dual 15" cones I believe. Is that still the case here...4-tower flagship? Was that one self-powered? If you have a subtower here, will that also be self-powered?
 

Audiophile Bill

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Mar 23, 2015
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Congratulations, Stavros. I admire your all out pursuits on this venture and hope to hear one day. Perhaps you will bring to Munich High End or would that be too much logistical hassle?
The compression driver mid bass is a very cool solution and only typically heard in the massive WE snail installations we hear at Munich. The manufacturing challenge of the scale of that horn (weight and thickness of the poplar plywood) is immense let alone trying to finish it to that degree. My mind boggles trying to get that colour and resin onto the wood uniformly and without runs or imperfections!
Would like to learn more about how you use the triple Fostex 8 inchers backloaded into the sub horn to get the desired output in the really low frequency stuff (say 20-30hz).
Oh and also time aligning the mid / tweeter with the really long mid bass horn?

Best regards.
 

the sound of Tao

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Jul 18, 2014
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Extraordinary Engineering and Artisan Craftsmanship combines Modern Art with Highest Fidelity to produce a Transducer Masterpiece, Bravo Stavros.
It is that epic sense of art in craft that I admire in these also. I’m not going to say I have the technical where with all to get all the implications of the design but I do admire the singular audaciousness of it. Then there is the wind tunnel formation of those big jumbo jet engine inspired horns. Part of me would love the tweeters to fall into line and fit the lovely bulbous spherical forms of the rest that bit better.

Sometimes our Sota gear can be a bit variable in design ethos and at times almost predictably robotic and some tend to the overscale and the awkward even, but these are anything but that. They are just OTT luxe and sensuous. Few perhaps will have the room to fit the scale as well as the expansive sculptural spirit of these but they are certainly intensely fluid and expressive moments of craft and art combined. Hats off to the unrelenting joyous madness of it all.
 
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Aries Cerat

Industry Expert
May 30, 2015
286
403
193
Thank you for the kind words of support!

I will start describing the design, the other way around, starting from the heart of the system, the crossover.

The four way design is 100% passively driven, and the crossover is passive.

The tweeter covers 2.500~100,000Hz and is filtered by a filter we have been developing for a while, the constant group delay filter. This filter prioritizes a linear(constant)( as much as physically and mathematically possible) group delay in the stopband.

The midrange filter (600Hz, 2500Hz) is also using constant group delay passband filters.

The midbass filter (100, 600Hz) is asymmetric with constant GD for the low pass section

Bass horns have their own filter (100Hz ) with no EQ and no shelve/boosting filters. The basshorns run as low as their natural basshorn acoustic loading allows, no tricks used (usually the norm in active basshorns) to boost low end.

Now for the true tricky part.(One may wonder why the crossover has power inlets)
The complete crossover, is reconfigurable , on the fly, using a complex circuit , controlled by specially designed circuit, and an Android Bluetooth application. All circuits and application developed in house of course.

This is not an active system , no dsp or A/D/A conversion made. All filters are analog passive circuits. The controller activates and switches a complicated array of components, (capacitors, multiple coils and transformers) to control many parameters of the design.

By doing so, the user, if they please doing so, while sitting in their listening spot, can tune the speaker to better suit their personal taste and most importantly , room.While using the phone application.

As an example of parameters a user can alter, is the power response of the midbass, the midrange, the bass horns (all independently), the group delay optimization of the tweeter,slopes between midbass and bass, slopes between mid and midbass among others.( there are some a bit more advance settings , but these are the main to be used by the user)

The level of the midbass and midrange can be adjusted using a multitap transformer, again controlled by the app.


The four independant inputs of the crossover allows for multimapping of course, a feat we used in our lab (using multiple Essentias)

Contendo2-images5.jpg

Contendo2-images2.jpg


Contendo2-images3.jpg
 

Audiophile Bill

Well-Known Member
Mar 23, 2015
4,320
4,008
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Thank you for the kind words of support!

I will start describing the design, the other way around, starting from the heart of the system, the crossover.

The four way design is 100% passively driven, and the crossover is passive.

The tweeter covers 2.500~100,000Hz and is filtered by a filter we have been developing for a while, the constant group delay filter. This filter prioritizes a linear(constant)( as much as physically and mathematically possible) group delay in the stopband.

The midrange filter (600Hz, 2500Hz) is also using constant group delay passband filters.

The midbass filter (100, 600Hz) is asymmetric with constant GD for the low pass section

Bass horns have their own filter (100Hz ) with no EQ and no shelve/boosting filters. The basshorns run as low as their natural basshorn acoustic loading allows, no tricks used (usually the norm in active basshorns) to boost low end.

Now for the true tricky part.(One may wonder why the crossover has power inlets)
The complete crossover, is reconfigurable , on the fly, using a complex circuit , controlled by specially designed circuit, and an Android Bluetooth application. All circuits and application developed in house of course.

This is not an active system , no dsp or A/D/A conversion made. All filters are analog passive circuits. The controller activates and switches a complicated array of components, (capacitors, multiple coils and transformers) to control many parameters of the design.

By doing so, the user, if they please doing so, while sitting in their listening spot, can tune the speaker to better suit their personal taste and most importantly , room.While using the phone application.

As an example of parameters a user can alter, is the power response of the midbass, the midrange, the bass horns (all independently), the group delay optimization of the tweeter,slopes between midbass and bass, slopes between mid and midbass among others.( there are some a bit more advance settings , but these are the main to be used by the user)

The level of the midbass and midrange can be adjusted using a multitap transformer, again controlled by the app.


The four independant inputs of the crossover allows for multimapping of course, a feat we used in our lab (using multiple Essentias)

View attachment 90453

View attachment 90452


View attachment 90451

Stavros - did you ever try the system with an analogue active crossover?

Are the 3 x Fostex fe208 sigma drivers wired in parallel? I saw that the impedance goes up from their nominal 8 ohms to 15-20+ sub 100hz so would make sense.
 

Aries Cerat

Industry Expert
May 30, 2015
286
403
193
Hello William

You can imagine, being an electronics company, a quite significant number of active filters were designed.
There are a number or types of active filters in prior art,and we did develop our own type of active system (tech of this type of filters is trickled down to the Aurora system btw :) ) that was used for both the developing of the filters as well as for auditioning the system.

A big proportion of the development of the passive filters were designed with the help of active filters as well.

Active vs passive is a big and interesting story, with pros and cons.We could discuss this on a separate thread with pleasure.

Cheers
Stavros
 
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Aries Cerat

Industry Expert
May 30, 2015
286
403
193
Look forward to reading more. Congratulations on your efforts to push the performance barrier with your company once again. I recall that the original Contendo had a sub tower almost the size of a big Wilson speaker...dual 15" cones I believe. Is that still the case here...4-tower flagship? Was that one self-powered? If you have a subtower here, will that also be self-powered?
Hello Lloyd

Thank you very much!

You recall correctly:)
Yes the initial design, in early stages, had big active sub sections (100Hz and up), using dual drivers,of the probably best long throw 15'' out there. It was a great sub section, using our tube crossover and over 2kw per channel.
Unfortunately, when you use horn loading down to 100Hz, there is simply no proper matching in speed and texture to the horn + sub section with conventional drivers. The speed difference(or as i prefer to call it, " trackability" of the lower section ) is there to hear it, especially when you compare it with proper basshorns. One can argue that under 80Hz the speed of the driver does not matter, i beg to differ. Once heard, cannot be unheard.

The new basshorns are passive, they have the same efficiency as the main speakers, and require no EQ nor shelve /boost filters. Thus you can power them from the main amps directly, or bi-amping them.

Cheers
Stavros
 

Billygxx

Well-Known Member
Nov 23, 2015
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There are actually six drivers per channel, the total impedance of the basshorn stack is ~6ohm.
My question is can I get a taller , narrower version of the subwoofer?
Of course while the speaker is now refined and beautiful, it‘s aesthetics are nothing compared to music it performs. As they say in audiophile land, it’s not how it sounds but how the speaker makes you feel that is important. In my humble, limited opinion, it outperformed any other speaker system at any price even in what was not a purpose built room. The sonic grace of a horn system with the gravitas of a complete Wamm system. One of only 3 systems I have heard that can reproduce the full spectrum of music with the dominance of a complete orchestra. Glorious.
A pic of a person standing next to the midrange horn would give one a concept of the massive complexity of machining a titanic wooden horn. The photographs just don’t convey the size of that upper bass, lower midrange mammoth trumpet. Hopefully others will have the opportunity to hear these magnificent beasts once we get them set up in the US. That is the only way to really fathom them.
I know we have a rule here against hyperbole but this system is a colossal(sorry again) achievement.
Great work Stavros!
 

Audiophile Bill

Well-Known Member
Mar 23, 2015
4,320
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My question is can I get a taller , narrower version of the subwoofer?
Of course while the speaker is now refined and beautiful, it‘s aesthetics are nothing compared to music it performs. As they say in audiophile land, it’s not how it sounds but how the speaker makes you feel that is important. In my humble, limited opinion, it outperformed any other speaker system at any price even in what was not a purpose built room. The sonic grace of a horn system with the gravitas of a complete Wamm system. One of only 3 systems I have heard that can reproduce the full spectrum of music with the dominance of a complete orchestra. Glorious.
A pic of a person standing next to the midrange horn would give one a concept of the massive complexity of machining a titanic wooden horn. The photographs just don’t convey the size of that upper bass, lower midrange mammoth trumpet. Hopefully others will have the opportunity to hear these magnificent beasts once we get them set up in the US. That is the only way to really fathom them.
I know we have a rule here against hyperbole but this system is a colossal(sorry again) achievement.
Great work Stavros!

Billy - what about upgrading from your existing Aries Cerat speakers to the Contendo Reference?
 

Mobiusman

Well-Known Member
May 25, 2010
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I use to think that my Von Schweikert Ultra 9's were big, but these speakers make then look like a speck of dust. Bravo and would love to hear them some time.
 

LL21

Well-Known Member
Dec 26, 2010
13,380
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...The sonic grace of a horn system with the gravitas of a complete Wamm system. One of only 3 systems I have heard that can reproduce the full spectrum of music with the dominance of a complete orchestra. Glorious.
...I know we have a rule here against hyperbole but this system is a colossal(sorry again) achievement.
Great work Stavros!
Wow...would love to hear these.
 

Willgolf

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Jul 22, 2019
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Gold Canyon, Az
What is the MSRP of these bad boys?
 

matthias

Well-Known Member
Mar 14, 2019
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Germany
The new basshorns are passive, they have the same efficiency as the main speakers, and require no EQ nor shelve /boost filters. Thus you can power them from the main amps directly, or bi-amping them.

Hi Stavros,
congratulations, this is extremely interesting!

Will you bring the complete Contendo II system to HE Munich this year for listening (or at least the new Aurora)?
Thanks

Matt
 
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JackD201

WBF Founding Member
Apr 21, 2010
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VERY handsome speakers Stavros. Congratulations!
 

Aries Cerat

Industry Expert
May 30, 2015
286
403
193
Hi Stavros,
congratulations, this is extremely interesting!

Will you bring the complete Contendo II system to HE Munich this year for listening (or at least the new Aurora)?
Thanks

Matt

Hello Matt

This pair is being loaded to be delivered to the owners (18 out of the total 20 crates of the speaker,loaded in the picture).

We will however bring the new kid, the Aurora ,to Munich.

Cheers
Stavros

IMG_20220318_121244.jpg
 

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