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GGNTKT Model M1

q3cpma

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#1

https://ggntkt.de/en/model-m1/
Just wondering if anyone had anything to say about it; impressions, even hearsays. This could be a nice addition to the Kii, Grimm and D&D new generation of Hi-Fi speakers.

Here are the specs and highlights:
* 119 dB peak level
* 140° x 100° constant directivity
* THD <0,3 % (@90 dB/1 m)
* Up to 200 Hz cardioid radiation pattern
* 280 Watt Class-D amplifier
* 39 Hz cut-off frequency (-6 dB)
* Sealed high-tech cabinet (5-axis CNC-milled basic structure made of Valchromat forms the housing and offers 30% higher stability than standard MDF boards)
* External electronics with Pascal amps and SHARC DSP connected via SpeakON
* Price: 5900€ for a pair with the electronics; apparently there's a more powerful version (280 -> 420 W per channel for 121 dB peaks) for 1000€ more

Quite competitive even if they're not full-range (though they seem to have a floorstander in the work).
 
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Mnyb

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#2
Very interesting speakers :) almost perfect execution of thier ideas .
I miss some information.

Is there a room correction software included ?

There is no built in xover for subwoofer(s)
 
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q3cpma

q3cpma

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Thread Starter #3
Very interesting speakers :) almost perfect execution of thier ideas .
I miss some information.

Is there a room correction software included ?
I don't think there's any DRC software given with any of those speakers,
There is no built in xover for subwoofer(s)
Yes, that's something of importance that do seem to be missing.

I guess asking them would be easier. I do wonder about the software side, too.
 
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q3cpma

q3cpma

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Thread Starter #5
Neat! Love the fact that it uses a compression driver and a biradial horn :)
Yeah, I too like the idea of well executed compression driver/horn (i.e. that goes beyond pure horn theory and tries to reduce significantly diffraction/throat reflections, like the M2). The low baffle step inducing wide baffle trend set by Grimm is also quite exciting; and it looks great, to be honest.

Incidentally, I consider Neumann's waveguide to be almost worthy of the same horn/waveguide attribute, seeing how deep they are.
 

beefkabob

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#9
Only one amp? Should be two. Wouldn't it be even better as a 3-way?
 

roland{at}GGNTKT

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#12
Hi there!

thanks for highlighting our Model M1. I was notified by our engineer that our active speakers were discussed here and so I joined this board.

My name is Roland and I'm the founder of GGNTKT – the company with the password-generator-name ;) (Right, its German for "Gegentakt"... and the fact that you do talk about the name, ensures that you will remember it). We started in 2018 and were in stealth-mode for about 12 months to develop Model M1 and also two others. As you might have guessed we have a strong orientation towards evidence-based design. I myself am no an acoustical engineer (at least I'm holding a computer science degree), but we joined forces with well-known talents in the industry and also have access to many Klippel tools, including the NFS. Coming from DIY I build my first speaker more the 25 years ago and over time passion grew into profession. In 2015 I co-founded Schanks Audio which was specialized in motional feedback technology and highly vertical integrated for such a small company.

I always wanted to have speakers with a certain level of aesthetics and industrial design, combined with the best possible acoustical performance in a given form factor. Yes, you could argue the B&O is also trying that, and its true. But I think they are a bit more on the design side and do sacrifice performance here and there. The reason why Model M1 (and also upcoming Model M2) has a wide baffle is because of that – I liked the design and its works acoustically very well.

Model M1 is a very compact speaker with less than 10l internal volume and you will be surprised when you see the only 140mm/5,5” deep/flat cabinet the first time. The goal was (1) very controlled radiation pattern with constant directivity, (2) high SPL and (3) distortion below hearing thresholds, whereas (2) + (3) do interact very much.

Obviously, we use the same SB Acoustics Aluminum drivers that Buchardt, Revel and others are using, since they are extremely low distortion designs (by former Scan-Speak masterminds). I even think it’s the best driver in its class, except the new Purify drivers (which were not available then). We decided against a ventilated cabinet, because in a small 2-way design it’s very difficult to get a clean midband even with passive radiators. Also designing a noiseless and resonance-free port is not that easy. So, went with a closed cabinet and to meet our SPL goals we had to put in three (!) SB drivers and a lot of amping power. That was a quite expansive decision but gave us the best results. The two drivers in the back are used to create a cardioid radiation pattern which extends the constant directivity to apx. 250 Hz. Below that frequency all three woofers do play bass in parallel (in phase). Since we have full three channels per speaker, we can apply different radiation patters (right now there is no-cardioid, supercardioid/135° and hypercardioid/180°).

As for the HF region we wanted drivers that radiate a plane wavefront which make the integration to any waveguide and therefore shaping directivity much easier and cleaner, so that’s why we went with a compression driver. Also, a nice side effect is the high SPL capabilities which are 5-10dB more than most dome tweeters, very useful in home cinema use cases. As evidence-based designers know there is no “tweeter-sound”, it all comes from radiation/directivity and partly from distortion (if above hearing thresholds). That is why for us there is no dogma in drivers types (domes, ribbon, AMT, Compressions, etc) and materials.

Because of the compact cabinet we decided to swap the electronics out, so all DSP-processing and amping is done outside for all six channels, so there is one 1U case to drive a pair of Model M1. We use Pascal U-PRO2S(D) class-d amps and do source our DSP from a German premium brand Fouraudio, because of their excellent software. Most of our filtering is FIR based, so Model M1 is linear phase 20 Hz – 20 kHz.

I could go on and write much more, but feel free to ask and have a look on some pictures:
https://www.instagram.com/ggntktaudio/

Thanks again,
Roland

PS: There will be Model M2 and a third home cinema Speaker (codename SRND), both before the end of the year...
 
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q3cpma

q3cpma

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Thread Starter #13
Hi there!

thanks for highlighting our Model M1. I was notified by our engineer that our active speakers were discussed here and so I joined this board.

My name is Roland and I'm the founder of GGNTKT – the company with the password-generator-name ;) (Right, its German for "Gegentakt"... and the fact that you do talk about the name, ensures that you will remember it). We started in 2018 and were in stealth-mode for about 12 months to develop Model M1 and also two others. As you might have guessed we have a strong orientation towards evidence-based design. I myself am no an acoustical engineer (at least I'm holding a computer science degree), but we joined forces with well-known talents in the industry and also have access to many Klippel tools, including the NFS. Coming from DIY I build my first speaker more the 25 years ago and over time passion grew into profession. In 2015 I co-founded Schanks Audio which was specialized in motional feedback technology and highly vertical integrated for such a small company.

I always wanted to have speakers with a certain level of aesthetics and industrial design, combined with the best possible acoustical performance in a given form factor. Yes, you could argue the B&O is also trying that, and its true. But I think they are a bit more on the design side and do sacrifice performance here and there. The reason why Model M1 (and also upcoming Model M2) has a wide baffle is because of that – I liked the design and its works acoustically very well.

Model M1 is a very compact speaker with less than 10l internal volume and you will be surprised when you see the only 140mm/5,5” deep/flat cabinet the first time. The goal was (1) very controlled radiation pattern with constant directivity, (2) high SPL and (3) distortion below hearing thresholds, whereas (2) + (3) do interact very much.

Obviously, we use the same SB Acoustics Aluminum drivers that Buchardt, Revel and others are using, since they are extremely low distortion designs (by former Scan-Speak masterminds). I even think it’s the best driver in its class, except the new Purify drivers (which were not available then). We decided against a ventilated cabinet, because in a small 2-way design it’s very difficult to get a clean midband even with passive radiators. Also designing a noiseless and resonance-free port is not that easy. So, went with a closed cabinet and to meet our SPL goals we had to put in three (!) SB drivers and a lot of amping power. That was a quite expansive decision but gave us the best results. The two drivers in the back are used to create a cardioid radiation pattern which extends the constant directivity to apx. 250 Hz. Below that frequency all three woofers do play bass in parallel (in phase). Since we have full three channels per speaker, we can apply different radiation patters (right now there is no-cardioid, supercardioid/135° and hypercardioid/180°).

As for the HF region we wanted drivers that radiate a plane wavefront which make the integration to any waveguide and therefore shaping directivity much easier and cleaner, so that’s why we went with a compression driver. Also, a nice side effect is the high SPL capabilities which are 5-10dB more than most dome tweeters, very useful in home cinema use cases. As evidence-based designers know there is no “tweeter-sound”, it all comes from radiation/directivity and partly from distortion (if above hearing thresholds). That is why for us there is no dogma in drivers types (domes, ribbon, AMT, Compressions, etc) and materials.

Because of the compact cabinet we decided to swap the electronics out, so all DSP-processing and amping is done outside for all six channels, so there is one 1U case to drive a pair of Model M1. We use Pascal U-PRO2S(D) class-d amps and do source our DSP from a German premium brand Fouraudio, because of their excellent software. Most of our filtering is FIR based, so Model M1 is linear phase 20 Hz – 20 kHz.

I could go on and write much more, but feel free to ask and have a look on some pictures:
https://www.instagram.com/ggntktaudio/

Thanks again,
Roland

PS: There will be Model M2 and a third home cinema Speaker (codename SRND), both before the end of the year...
Thanks a lot for coming here to discuss your speakers! Some questions:
* Can you give some measurements? Ideally, a spin-o-rama with some distortion information; at least some on-axis/off-axis data. The dropbox link to the pdf on instagram is dead. Here's what I managed to get from instagram
specs.jpg

* Do you have more information about the software side? How is the DSP controlled, for example. Being a GNU/Linux user, I wonder if there's an API allowing to upload filters or something.
* As asked, how are we supposed to integrate one or more subwoofers?
* Warranty length?
* You talked about MFB, is this used here? Would make sense in a small sealed enclosure where distortion does matter.
 
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#14
Hi @q3cpma,

* Can you give some measurements? Ideally, a spin-o-rama with some distortion information; at least some on-axis/off-axis data. The dropbox link to the pdf on instagram is dead. Here's what I managed to get from instagram
There should be some graphs on the website: https://ggntkt.de/en/model-m1/technische-daten/ or as PDF
We will provide the Klippel NFS measurements next month, since there is a new software revision and minor tweaks we want to cover.

* Do you have more information about the software side? How is the DSP controlled, for example. Being a GNU/Linux user, I wonder if there's an API allowing to upload filters or something.
It's supplied by Fouraudio, they do all the soft- and hardware. Many technics are borrowed from PA, like dynamic-EQ, look-ahead limiter...
You can have a look here (there is a GUI for enduser and developer).


* As asked, how are we supposed to integrate one or more subwoofers?
Right now there is no subwoofer integration based on the platform we use. So you have to manage it all external.
But to be honest – in small rooms and with music content, i would doubt that you need a sub. In home cinema applications the bass management is integrated into the AVR anyway. But I see your point on having the function option to do so.

* Warranty length?
It's 3 years if you register the product: https://ggntkt.de/en/produktregistrierung/

* You talked about MFB, is this used here? Would make sense in a small sealed enclosure where distortion does matter.
No, we decided against MFB. Four main reasons:
  • Costs: For a driver modified and equipped with MFB sensor you can buy 2-3 "regular" drivers (that size) and guess what, which constellation performs better overall?
  • Performance: The SB drivers have exceptional low distortion in the mids, so MFB is just not needed here.
  • Implementation: You are limited to sealed enclosures, which is fine for Model M1, but not for Model M2 (which will be ventilated).
  • Implementation: You add complexity and potential risks of failure.
MFB is a topic by itself, I know the numbers. You have to decide whether it is useful in every single application individually. That is what we did und still do. As for Model M1 it made no sense, we reached our goals better with more drivers.
 

GelbeMusik

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#15
Nice, really. A bit of an Apple (c) it has, or of a glider plane.

An other contender to the cardioid tribe, well. I have one question and another remark:

What about placing the M1 close (50 centimeter or so) against a backwall?

The cost for an upgrade option for some bigger capacitors is about 550 Euro ( eq. $ ). Such markup policy extinguishes my enthusiasm immediately.
 

roland{at}GGNTKT

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#16
What about placing the M1 close (50 centimeter or so) against a backwall?
Model M1 was designed to be placed near to a backwall and the cardioid directivity pattern also helps to do so, as there is less energy behind the speaker. In our showroom we only have apx. 15cm/5-6" space left to the wall, so it's almost on-wall. I think in modern listening areas people don't accept speakers standing "in the middle" of the room anymore (since their TVs are flat).

However depending on the exact distance to the wall, you have to fine tune/EQ a bit because of the boundary effects. That can be easily done in our software (access vis USB).

The cost for an upgrade option for some bigger capacitors is about 550 Euro ( eq. $ ). Such markup policy extinguishes my enthusiasm immediately.
Model M1 works very well without the extra caps, but there might be certain circumstances that demand even more. We decided to deliver a setup that probably fits 90 % of the customers, but leave it up to them to decide which configuration they prefer. Freedom of choice.

As for the price, please keep in mind that we are talking about additional 3x PCBs with 48x high-quality (low-ESR, 105°C) caps in sum. That's a lot of material.
 

GelbeMusik

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#17
As for the price, please keep in mind that we are talking about additional 3x PCBs with 48x high-quality (low-ESR, 105°C) caps in sum. That's a lot of material.
As for the price, please keep in mind that we are talking about additional 3x PCBs with 48x high-quality (low-ESR, 105°C) caps in sum. That's a lot of material.[/QUOTE]

So, no 'audiophile' grade pricing. I'm enthusiastic again, thank You!


However depending on the exact distance to the wall, you have to fine tune/EQ a bit because of the boundary effects..
Tja, there's my doubt coming from, the bondary effect. Of course You know of the concept of "mirror sources" (germ.: spiegelquellen). Wouldn't these render the former cardiod a quadrupole, with quite different behavior? From some amateurish calculations I concluded that a cardiod would lose all its advantages when placed, say, less than a wavelength against a backwall. It made me stop fumbling with cardioids any further. I came that far to measure the abovementioned affect, and then stopped.
 

roland{at}GGNTKT

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#19
Tja, there's my doubt coming from, the bondary effect. Of course You know of the concept of "mirror sources" (germ.: spiegelquellen). Wouldn't these render the former cardiod a quadrupole, with quite different behavior? From some amateurish calculations I concluded that a cardiod would lose all its advantages when placed, say, less than a wavelength against a backwall. It made me stop fumbling with cardioids any further. I came that far to measure the abovementioned affect, and then stopped.
The cardioid pattern of Model M1 does not shape the bass, it is used for directivity control >250 Hz. So actually mirror sources are reduced, because as I said, above that frequency there is less energy behind the speaker which could be reflected.
 

GelbeMusik

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#20
The cardioid pattern of Model M1 does not shape the bass, it is used for directivity control >250 Hz. So actually mirror sources are reduced, because as I said, above that frequency there is less energy behind the speaker which could be reflected.
I'm thinking like this. In free field, on the single mountains peak of a distant tropical island, where all boundaries are very far away, the loudspeaker behaves as a cardiod. In case the microphone position is not too close. This is the far and free field, cardioid with, referring to M1 three sources. For this specific case a clear and easy construction recipe exists. Some distant mounting position, some delay and inverted, done.

Now change the position to close to a backwall. Due to the mirror sources (the wall reflects sound) the cardioid becomes a quadrupole, effectively. That messes with all the fine maths, which applied so happily to the abovementioned case of far 'n free field.

Your argument goes that, since it's a cardioid, the backward radiation is null or so. Hence the backwall is quiet.

I say, that with a backwall the cardioid pattern doesn't form (that easily). Hence the backwall is not quiet.

I only wanted to know, if there are some settings available to cope with the near by backwall, roughly.
 
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