"The Clue" - ny amerikansk högtalare

[Laila]

Borde det inte gå att skaka fram ett par i Sverige?

Det är enkelt.

En standard HiFiKit-låda. En bas och en diskant. Bygg ihop. Färdig.

Smart, att ingen tänkt på det tidigare?

Joerå . . . redan på sjuttiotalet . . .

[phon]

[celef]

men vad kan vara anledningen till skapandet av denna högtalaren, vad är det som har hänt, har sjöfn ställt krav på guru om en mer hemmaanpassad högtalare och fått nobben, sjöfn har då blivit sura och börjat gapa å skrika för att sedan kavlat upp skjortarmarna för att skapa sig något eget?

[Ragnwald]

Hm... är det möjligen den nya i6 ?

Parts Expresslådorna är väldigt välbyggda. Zaphs använder dem flitigt.

[Objektivisten]

men vad kan vara anledningen till skapandet av denna högtalaren, vad är det som har hänt, har sjöfn ställt krav på guru om en mer hemmaanpassad högtalare och fått nobben, sjöfn har då blivit sura och börjat gapa å skrika för att sedan kavlat upp skjortarmarna för att skapa sig något eget?

I ain't gotta clue.

[Jacro]

Hello Everyone,

I am the designer of 'the clue' loudspeaker.

I noticed that there appeared to be some interest and I would be glad to discuss the clue or answer any questions that anyone might have.

I alway enjoy reading your forum, albeit with the help of Google translate.

I hope that posting in English is acceptable.

Best regards,

- James

[nilsviktor]

Vi noterar att det spekuleras om vårt förhållande med Sjöfn. Det kan vara värt att notera att vi inte haft samarbete med dem sedan hösten 2008. De hade oss med på sin hemsida längre än så, men det var inget vi kunde göra något åt.

[screen]

Vi noterar att det spekuleras om vårt förhållande med Sjöfn. Det kan vara värt att notera att vi inte haft samarbete med dem sedan hösten 2008. De hade oss med på sin hemsida längre än så, men det var inget vi kunde göra något åt.

Kan det vara värt att notera varför också?

[JanBanan]

Hello Everyone,

I am the designer of 'the clue' loudspeaker.

I noticed that there appeared to be some interest and I would be glad to discuss the clue or answer any questions that anyone might have.

I alway enjoy reading your forum, albeit with the help of Google translate.

I hope that posting in English is acceptable.

Best regards,

- James

Welcome, James!

[paa]

Hi Jacro!
Please tell us about your history with loudspeakers.

[Nattlorden]

Welcome Jacro.

If you're able to manage it with through the translator - do make a footer which tells of your commercial involvement - it's a forum rule to have it like that.

[nilsviktor]

Vi noterar att det spekuleras om vårt förhållande med Sjöfn. Det kan vara värt att notera att vi inte haft samarbete med dem sedan hösten 2008. De hade oss med på sin hemsida längre än så, men det var inget vi kunde göra något åt.

Kan det vara värt att notera varför också?

Nej. Vi tyckte olika bara.

[celef]

välkommen jacro, kul att ha dig här, berätta gärna mer om högtalarna, är det verkligen parts-express-lådor?

[Jacro]

Hi Jacro!
Please tell us about your history with loudspeakers.

First, thank you for the warm welcome!

My involvement in music reproduction goes back to childhood, but professionally it started in 1973 when after studying psychoacoustics, acoustics, and power electronics in college, as my final college project I developed a new type of Regenerative Transmission Line (currently produced by Wisdom Audio) similar to what is often referred to as a Tapped Horn.

After college I developed loudspeakers for Audionics of Oregon, the importer of the British Radford electronics at the time.

In 1975 I opened a high-end audio store called Definitive Audio, in Seattle Washington, which continues today with three stores, but I don’t participate much anymore, as I stopped running the store in 1985 and continued as Chairman of the board of directors.

With funding from Definitive Audio, in 1976 I started extensive 9-year research into psychoacoustics, acoustics, electro-acoustics, and power electronics, in an effort to define the remaining issues that keep us from having the effect of a live concert in our homes.

I’m not sure I can remember all the loudspeaker systems I’ve developed since I started professionally in about 1974 but I will list a few of the products I developed that some of you may be familiar with (I’m not sure how many products that were known in the USA were also visible in Sweden).

Audionics of Oregon:
TL-30
M33

Snell: Type One (concept and proof of concept prototypes)

Fulton (FMI) J-Modular Premiere Subwoofer and Supertweeter

Speakerlab Delta-i Hybrid

Satterberg MW2 mid-woofer for the Rogers LS3/5a

Carver Corporation:
The Carver Amazing Loudspeaker
(Planar magnetic line source/Dipole bass 12”x 4)

Carver/Toshiba Surround Sound Television Systems

JBL/Philips Projection TV Sound Systems

Dipole Surround Patent licensed to Lucasfilm/THX

Dahlquist DQ40, DQ30, DQ16, DQ6

American Technology Corp: (Now LRAD Corporation)
Hypersonic Sound (Hyper directional, Ultrasonic-to-Audio Parametric loudspeakers)

LRAD Long Range Acoustic Device (beam formed 1.5 kilometer communications)

Stratified Field; constant directivity electrostatic loudspeakers

NeoPlanar; planar magnetic transducers

The Clue

I have about 30 or 40 patents in the field of audio, mostly loudspeakers, power amplification and signal processing and continue to do consulting for many in the industry such as SJÖFN HiFI, Atlantic Technology, Magnepan and Wisdom Audio.

I hope this is the kind of answer you were looking for. If you wish to have me expand on anything in particular or answer something else, let me know.

Best regards,

James Croft

[KarlXII]

Impressive resume there, James. Jeez.


Again, Welcome to faktiskt.se.

Any chance we will see these speakers over here?

[paa]

My involvement in music reproduction goes back to childhood, but professionally it started in 1973 ...

...
Snell: Type One (concept and proof of concept prototypes)

Thanks for the resume.
Did you come up with the concept of the Snell Type One?
What is your comment to that design today? Could that floor bound tweeter solve any of todays reproduction problems, or has evolution found better ways by now?

By the way, this is my attempt at full range floor support, a mini speaker built just for fun, inspired by Stig Carlssons prototypes and patents:
http://user.faktiskt.io/paa/minione_8.jpg
I also believe Stig Carlsson was somewhat inspired by the Type One at that time.

[Jacro]

Impressive resume there, James. Jeez.


Again, Welcome to faktiskt.se.

Any chance we will see these speakers over here?

Thank you. With old age comes long resumes'.

I'm not sure of the President's (Lars Erickson) plans for export. I know he is a big fan of all things Scandinavian, and I would expect that he would like to have a good reason to visit more often. So, eventually, he may introduce The Clue in Sweden or other parts of Europe. As you may know, he is the US importer for Supra Cables.

For now, we are very busy working to build enough for the US market and it appears that will keep us busy for awhile.

Cheers,

- James

[Jacro]

My involvement in music reproduction goes back to childhood, but professionally it started in 1973 ...

...
Snell: Type One (concept and proof of concept prototypes)

Thanks for the resume.
Did you come up with the concept of the Snell Type One?
What is your comment to that design today? Could that floor bound tweeter solve any of todays reproduction problems, or has evolution found better ways by now?

By the way, this is my attempt at full range floor support, a mini speaker built just for fun, inspired by Stig Carlssons prototypes and patents:
http://user.faktiskt.io/paa/minione_8.jpg
I also believe Stig Carlsson was somewhat inspired by the Type One at that time.

Thank you for the Carlsson pic! I hadn't seen that particular model.

Yes, I came up with the concept for the Snell Type One, but in late 1976, when I did a patent search, I found Snell's original patent (US 3,964,571) had somewhat anticipated the idea, even though he was producing only the Type A at the time. So, I contacted Peter Snell and presented the concept to him, along with sketches of my configuration and test data (Mine was 8" two way, Audax and Peerless, Snell's was 10" two way Audax all around). It wasn't very nice looking, and it wasn't very practical with a 60 cm 'tongue' sticking out for people to trip over, but the performance was rather special. I had adjusted my prototypes to sound almost identical to the QUAD 57's placed on the floor.

Anyhow, I was busy with other projects and didn't want to have a patent dispute, and I was working on making a better version anyhow, as the one problem with my original approach, and the production Type One, was that the image is too low... similar to sitting up in the balcony and looking down at the orchestra. But, it was remarkably uncolored and transparent.

Two or three years later (in about 1979 I believe), Snell came out with the Type One and I offered it for sale at my audio store. Unfortunately, it went out of production after just a couple years. Even so, it was the beginning of something special and I was surprised that they abandoned it so completely. But, also, Peter Snell died around that time, so I think he would have done more with it if he had lived longer.

Yes, the concepts still have much validity today and about 12 years ago, I built prototypes of some of my next generation thinking on the idea, of which I hope to get back to in time.

With all the DIY work that the groups in this forum do, I'm sure it would be a fun project for many here to try. The patent is public domain, so have fun!

All the best,
- James

[BB]

Carver Corporation:
The Carver Amazing Loudspeaker
(Planar magnetic line source/Dipole bass 12”x 4)

James Croft

Hi James,

Cool to see that you have been working with line source systems.
Maybe we can have a chat over a beer next time I go to US..?

Best,
//BB

[paa]

[Thank you for the Carlsson pic! I hadn't seen that particular model.
...

..., and the production Type One, was that the image is too low... similar to sitting up in the balcony and looking down at the orchestra. But, it was remarkably uncolored and transparent.

Yes, the concepts still have much validity today and about 12 years ago, I built prototypes of some of my next generation thinking on the idea, of which I hope to get back to in time.

With all the DIY work that the groups in this forum do, I'm sure it would be a fun project for many here to try. The patent is public domain, so have fun!

All the best,
- James

James,
With my small speaker the sound stage can at best be quite a bit higher than one would expect, but then sometimes not.
Do you see a possibility to raise the heigth of the sound stage from loudspeakers whith the drivers placed so close to the floor?
Here is an in-depth look into the design of the never finished Carlsson Three Way speaker:
http://www.faktiskt.se/modules.php?name ... c&p=502903

[Jacro]

välkommen jacro, kul att ha dig här, berätta gärna mer om högtalarna, är det verkligen parts-express-lådor?

jacro welcome, good to have you here, tell me more about the speakers, it's really parts-express-boxes?

Celef,

I’m not sure which aspects of the design you are most interested in, so I will discuss some of the design concepts and please feel free to ask more questions if I don’t provide what you were looking for.

I believe that if the science of audio is well understood by the designer, then high quality sound doesn’t have to have high cost. Ultimately, if the design is truly advanced, the “quality” of sound should be able to be made to equal the state of the art for a modest price. With effective design, only the “quantity” of sound should drive the cost upwards, as one attempts to have the system play much louder and fill larger spaces.

The President of SJÖFN HiFi, Lars Erickson and I have known each other since the late 1970s. He and I always talked about developing a new loudspeaker that would challenge the very best, but could be affordable to those that loved music but didn’t have a lot of money to spend. We had both gone different directions for the last 25 years but we linked back up a couple years ago and immediately started where we left off, both feeling like it was time to build the speaker we had discussed so many years ago.

I had been working for a few years on new room interaction and transducer technologies and had developed a few different approaches, one of which looked like it would meet the requirements for our high value/low cost concept.

I have worked with a number approaches that attempt to ignore the room, and substantially provide direct sound only. While these can be very effective, they are at this stage in their development, rather expensive, and fairly inefficient. I wanted to have a more practical product, but one that still dealt with the “room problem”. So instead of fighting the room, and attempting to ignore it, I went in the other direction and worked to embrace the room, but to decorrelate its affects in a manner that minimized room coloration and provided great leverage to the acoustic power delivered to the listener, allowing for a modest sized system to create the level of dynamics that would be satisfying.

To start with, The Clue is based on an “enhanced” full range driver concept. The 100 mm ‘woofer’ was originally conceived as a full range driver. Full range drivers being seamless, without crossovers, have a certain desirable potential (Peter Walker of Quad was working on a full range dynamic driver as one of his last designs) but, at least in conventional form, even the few that have good on-axis response also have very poor, collapsing power response in the upper octaves, tending towards a rather ‘dark’ sound.

I wanted to have the coherence of a full range device but also with optimum power response. So, we developed the ‘woofer’ to be very smooth and wideband on axis, while using the tweeter in an unconventional manner to contribute primarily increased off-axis energy as the full-range driver dispersion starts to collapse above 2 to 4 kHz. The dispersion driver comes on stronger with increased frequency, filling in more and more of the off-axis energy while they operate together with the woofer still dominating the on axis response up to about 11 kHz wherein above that frequency, the dispersion driver starts to take over both the on and off-axis energy maintaining consistent power response to beyond 30 kHz. (I hope that is a clear enough explanation).

To further enhance the seamless transition, the dust-cap of the woofer utilizes the same silk material as the tweeter diaphragm. All of this provides a very well integrated and low coloration wave front over a consistent angle of dispersion across the entire bandwidth.

The woofer is unusual in that it has both a large linear X-max and smooth, extended upper range capability. We worked hard to get as much large signal capability (quantity) as possible while maintaining a cost effective structure. The woofer is rather expensive, but could not be built for less and still meet our bandwidth and large signal design targets.

The low frequency alignment is based on a Keele Cs = 0.58, step-down tuning, as disclosed in his 1974 AES presentation, but without requiring an active equalizer.

The very narrow use model is that of the sequential engagement of boundary gain and specific left/right speaker spacing to provide mutual coupling gain at the maximum excursion frequency. This is to passively duplicate the gain of a Q of 2 high-pass equalizer down to Fb (but with much greater acoustic power to excursion ratio), and coordinate that with a golden ratio diversification of specular boundary reflections, such that the arrival at the listener is not colored by combing of the amplitude response due to correlated reflections cancelling on-axis energy at odd half wavelengths.

This diversified, half space approach achieves very satisfying sound pressure levels while maintaining useful response to below the tuning frequency without reaching non-linear excursion from about 28 Hz upward, providing approximately a 1/3 octave deeper bass extension than the active version of the Keele alignment.

The near boundary coupling has some aspects in common with the design practice of others, such as Carlsson, Audio-Pro, and Ino-Audio, but also includes novel attributes that allow us to realize our specific target functions.

The all production units are matched within less than ½ dB to The Clue reference standard pair.

These are just a few of the design elements, and they don’t really represent a complete set of attributes that determine the sound quality of The Clue, but hopefully I have provided some useful information.

In terms of the questions about the enclosure, originally we designed a different cabinet structure with optimized internal ratios, and a form fit to the boundary coupling. In keeping with our goal of maximizing sound for cost, we found that if we modified the internal cabinet for controlled wave development and applied efficient bituminous damping to remove any remaining panel resonances, that we could use a cabinet built at the same factory as the Parts Express enclosures and equal or exceed the performance of our original custom cabinet for less than half the cost.

The goal with The Clue is to design from a systems approach, wherein increased money is spent only where it actually provides a sonic improvement and cost is reduced wherever it has no impact on sound quality.

This is achieved by way of a process that I call “Design from Local and Global Variables” using “Impedance Interface Matching”, but that is a much longer story and I have probably already carried on longer than what the questioner was looking for.

I hope this provides some of desired answers. Let me know if there are any more questions.

Cheers,

- James

[Jacro]

Carver Corporation:
The Carver Amazing Loudspeaker
(Planar magnetic line source/Dipole bass 12”x 4)

James Croft

Hi James,

Cool to see that you have been working with line source systems.
Maybe we can have a chat over a beer next time I go to US..?

Best,
//BB

Hi Bo,

I very much look forward to chatting with you about line sources and planar magnetics over a beer, or two... I'll buy.

Cheers,

- James

[Jacro]

[Thank you for the Carlsson pic! I hadn't seen that particular model.
...

..., and the production Type One, was that the image is too low... similar to sitting up in the balcony and looking down at the orchestra. But, it was remarkably uncolored and transparent.

Yes, the concepts still have much validity today and about 12 years ago, I built prototypes of some of my next generation thinking on the idea, of which I hope to get back to in time.

With all the DIY work that the groups in this forum do, I'm sure it would be a fun project for many here to try. The patent is public domain, so have fun!

All the best,
- James

James,
With my small speaker the sound stage can at best be quite a bit higher than one would expect, but then sometimes not.

Do you see a possibility to raise the heigth of the sound stage from loudspeakers whith the drivers placed so close to the floor?
Here is an in-depth look into the design of the never finished Carlsson Three Way speaker:
http://www.faktiskt.se/modules.php?name ... c&p=502903

It IS possible, by a few different methods, to raise the height of the sound stage with the speaker boundary coupled close to the floor. As with many acoustical subjects it is difficult to provide a useful and thorough answer in a few paragraphs in this forum, but I'll mention a few things to hopefully at least stimulate some thinking and discussion on the matter.

The psycho-acoustics of the situation is that we receive most of our information relative to image height from frequencies above 4 kHz, at least when we keep our head perfectly vertical. in actuality, we are always tilting our heads sideways a small amount as we listen to music and this allows our ear/brain system to start to use left/right ear comparison for vertical imaging, which lowers the frequency sensitivity down below 1 kHz for vertical detection.

Even so, one approach is to use the midrange or woofer/midrange driver floor coupled, while placing the tweeter up at ear level, crossing over at about 2 to 3 kHz with precision 8th order slope crossovers to minimize lobing in the vertical polar response at and near the crossover frequency. With this approach the tweeter provides the height information and the boundary driver operates below 3 kHz where it is most important to eliminate correlated reflections (those arriving equally at both ears, such as front wall, floor and ceiling reflections). This approach has a number of things that have to be carefully optimized to work effectively, (such as perfectly matched tweeter/midrange horizontal directivity at the crossover frequency) but it can be made to work reasonably well.

Another approach is to use both the tweeter and midrange drivers boundary coupled to the floor, and use altered frequency response above 4 kHz to mimic the pinna derived frequency changes that normally tell the ear/brain system that an image is elevated. While this can work, it tends to vary in its effectiveness depending on the listener. Additionally, the ripple that one needs to invoke to get this effect is difficult to optimize for a variety of reasons, one being that one wants the ripple to have enough amplitude and bandwidth to stimulate the ear to sense elevation of image, while at the same time not to be so high in amplitude and broad band that it colors the tonal balance.

Again, I must mention that there are many subtle issues that must be dealt with to make these types of approaches work well without side effects causing audible tonal and spatial colorations.

I hope this answers your question.

Best regards,

- James

[RogerJoensson]

with the woofer still dominating the on axis response up to about 11 kHz wherein above that frequency, the dispersion driver starts to take

So widely centered around (or mainly below?) 11 KHz you have two drivers several inches apart outputting equal levels? How have you solved the vertical dispersion, without getting deep cancellations only slightly above and below height center? -Or is this a design feature?

[Jacro]

with the woofer still dominating the on axis response up to about 11 kHz wherein above that frequency, the dispersion driver starts to take

So widely centered around (or mainly below?) 11 KHz you have two drivers several inches apart outputting equal levels? How have you solved the vertical dispersion, without getting deep cancellations only slightly above and below height center? -Or is this a design feature?

Roger,

I can share part of 'what' we are doing in this regard, but 'how' we do it must remain a trade secret.

The way this approach of enhanced power response can be made to work successfully without interference is that the outputs of the two drivers are tailored in a unique manner such that the through the overlap region, the dispersion driver contributes more off-axis energy than on-axis energy, and the full-range driver contributes more on-axis energy and less off-axis energy. The amounts that each contributes to the on or off-axis energy varies with frequency, but at any given frequency, and axis, they are not providing equal energy, so the interference is minimized and good response is maintained above and below the listening axis.

We work hard to maintain smooth response at all angles as we want to have smooth response at the listening axis and also smooth response for most room reflections, to have good first arrival response and also a balanced spectrum for the delayed, room response.

Best regards,
- James

[paa]

James, would it be possible to push this concept with a full range driver and a filler tweeter to ever larger sizes, do you think?

[Piotr]

Interesting reading, welcome to faktiskt Jacro!


/Peter

[RogerJoensson]

The way this approach of enhanced power response can be made to work successfully without interference is that the outputs of the two drivers are tailored in a unique manner such that the through the overlap region, the dispersion driver contributes more off-axis energy than on-axis energy, and the full-range driver contributes more on-axis energy and less off-axis energy. The amounts that each contributes to the on or off-axis energy varies with frequency, but at any given frequency, and axis, they are not providing equal energy, so the interference is minimized and good response is maintained above and below the listening axis.

So, in short. -The smooth/tailored power response is to heal the off-axis cancellation of the direct radiated/unreflected sound (due distance between drivers)?

[Jacro]

James, would it be possible to push this concept with a full range driver and a filler tweeter to ever larger sizes, do you think?

Generally, yes, it is scalable, but to work without compromise, the basic architecture must change with larger devices, particularly if one wishes to maintain the same transition bandwidth and corner frequencies.

For what we wanted to achieve, The Clue is the best size that still allows standard driver constructions to be effective and for the upper frequency transition frequencies to be in the right place while still being able to generate adequate low frequency extension.

- James

[Jacro]

The way this approach of enhanced power response can be made to work successfully without interference is that the outputs of the two drivers are tailored in a unique manner such that the through the overlap region, the dispersion driver contributes more off-axis energy than on-axis energy, and the full-range driver contributes more on-axis energy and less off-axis energy. The amounts that each contributes to the on or off-axis energy varies with frequency, but at any given frequency, and axis, they are not providing equal energy, so the interference is minimized and good response is maintained above and below the listening axis.

So, in short. -The smooth/tailored power response is to heal the off-axis cancellation of the direct radiated/unreflected sound (due distance between drivers)?

Well, I would say it a bit differently. The smoother power response of the combined system is to optimize the direct and off-axis responses to combine the most accurate direct arrivals while also keeping the reverberant field well balanced. By having the off axis energy delivered independently from the on axis information, I attempt to have any particular angular vector from the system maintain smooth response, but at that vector, to have the energy dominated by either the dispersion driver or the full range driver, not shared, through the overlap region, so that the interaction is minimized.

As an analogy, think of the comparison being that convention speakers have a crossover between upper and lower frequencies, wherein we are attempting to have a crossover between on-axis and off-axis energy, at least over a certain band of frequencies.

I know it is probably somewhat confusing, but it is a bit difficult to explain more clearly without telling more about how we implement the effect.

I hope this helps at least make it somewhat clearer.

All the best,

- James