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Focal Sopra Part 2- The Obsession with Midrange

Posted on 15 February 2016

Welcome to our second installment on the innovative technologies employed in the new Focal Sopra Loudspeaker, this one focusing on the design of the midrange section. Midrange frequencies are undoubtedly one of the most complex areas of a speakers design and the most demanding musically, it is also a key element of the sound signature of all Focal Loudspeakers. The performance of the midrange driver is critical. On one hand, there must be a smooth transition to the bass driver, while on the other, it must be tuned to the tweeter in terms of dispersion and acceleration.  The Sopra design team have approached this dilemma with a series of exciting advancements in midrange driver design which I will expand on below.


W COMPOSITE SANDWICH CONE

The "W" composite sandwich cone permits total optimisation of the frequency response curve, thanks to the total control of three key parameters: lightness, rigidity and damping. At Focal, the letter "W" means Glass/ Glass, as it usually has two sheets of woven glass tissue that are "sandwiched" onto the structural foam core. The cone structure is more homogeneous and its behaviour in flex is much more superior than Kevlar® or Aramid fibre .
         
These unique characteristics of lightness and rigidity provide control of the signal transmission speed inside the material. Adjusting the thickness of the structural foam allows a very precise control of the "W" cone's damping. The variation of the number of glass fibre sheets and the thickness of the central foam can easily optimize the cone's behaviour according to the desired frequency range. When listening, the sound of the "W" cone is entirely transparent, has an excellent phase response and has a very low distortion rate (rigidity 20 times higher than Kevlar® or Aramid fibre).

 

TMD - TUNED MASS DAMPER

For the past 20 years, Focal have been working on mastering the "break up" (the frequency at which the cone becomes deformed, leading to distortion) of their 3rd generation "W" cones. Today, thanks to the power of finite element analysis, Focal's design teams have developed simulation software to visualise the dynamic behaviour of the suspension which connects the cone to the basket, thus revealing the performance issues requiring attention.

 

The problem is now well known: there  is a sudden change in mechanical impedance where the wave passes from the cone to the surround, which itself radiates sound and has a "boomerang" effect, causing deformation of the cone. Many attempts to resolve this have been considered by Focal's competitors but none is satisfactory, since all are detrimental to cone travel and cause dynamic compression.

Following the discovering of these issues, Focal had to conceive the approach to solve them. The solutions already known for increasing the damping properties of the suspension all result in an increase of the mass which consequently alters definition. The answer came from a technology used in earthquake-resistant skyscrapers and which is also used for the suspension on racing cars!  This technology is called a "Tuned Mass Damper": an additional mass oscillates in opposition to the resonance frequency to control it.

It was used with great success in the suspension of the Renault R25 F1 car in 2005 and was quickly banned because it was considered anti-competitive by the FIA. It is also the basic principle of anti-seismic systems for modern skyscrapers. This device offers major advantages. The speaker engineers were able to:

  • Use an exponential cone profile that extends the bandwidth to more than 5kHz and thus achieve better transient response;
  • Choose a very light surround, eliminating the resonance that is even stronger when the mass is low;
  • Damp resonance in the direction of the sound radiation (the radial plane) whereas competitors' devices damp circumferential resonances of the suspension.)

Thus Focal are able to combine benefits which were previously irreconcilable: low mass, optimum damping and extension of the frequency response. This leads to several benefits at the listening level:

  • Improved transient response coupled with a flat frequency response and reduced distortion, of the order of more than 50 per cent in an area where the ear is highly sensitive around 2kHz.
  • This results in more accurate timbre, improved definition and better stereo imaging.

To clarify the last point, the resonance of a conventional surround blurs the soundstage, especially when the resonance is marked. TMD suspension eliminates the problem at its source.

Focal's Tuned Mass Damper (TMD) consists of two tubular rings moulded onto the surround. This simple solution, perfected thanks to new software, stabilises the dynamic behaviour of the surround according to resonance, thus avoiding deformation of the cone without afflicting the dynamics.

Two moulded circular beads in the surround form the tuned harmonic damper. While this appears to be a simple solution, over a hundred different configurations were tested to optimise the result.

A committed research project  thus enabled Focal to develop a remarkable solution by addressing the problem at its source, without limitation of cone movement, using a "TMD" suspension for which a patent was filed in the third quarter of 2014.

VISUAL ANALOGY OF THE SURROUNDS- Left shows no TMD or default configuration, Right shows with TMD suspension

NIC - NEUTRAL INDUCTANCE CIRCUIT


STABILISING THE MAGNETIC FIELD

The precision and detail of audio reproduction depends on the stability of the drivers magnetic field. This stability is compromised by three factors which tend to modulate the magnetic field:

  1. the movement of the voice coil (Lenz's law),
  2. the current passing through it (Foucault current),
  3. the frequency.
Consequently, the voice coil, and all the moving parts, including the cone, are located within the magnetic field which becomes too variable, and leads to loss of precision.

 

THE SOLUTION- NEUTRAL INDUCTANCE CIRCUIT TECHNOLOGY

After three years of research and the development of simulation software which makes it possible to visualise these complex interactions, Focal engineers have created an incredibly stable magnetic circuit for the Sopra line. The solution, (NIC technology), lies in a Faraday ring whose dimensions, materials and positioning were optimised to make the magnetic field no longer affected by the position of the voice coil, by the amperage or the frequency of the current passing through it.

 

To implement this solution Focal developed a new midrange driver magnetic circuit for the Sopra line. A central Neodymium magnet is topped with a ferromagnetic pole piece brought to saturation by a second Neodymium pellet above it. The field is looped by a ferromagnetic circuit dimensioned to avoid saturation. Finally a Faraday ring is carefully positioned further to reduce distortion below 1kHz.


The end Result ...

Focal have now applied two major developments to the Sopra's midrange driver:   the harmonic damper suspension "TMD" and the  new magnetic circuit "NIC".

It is interesting to see the combined effect of these two innovations on overall performance. The results can definately be heard in listening tests:
  • extended frequency response for better transient performance and thus better definition
  • high linearity in the critical region 1-3kHz for improved timbral accuracy
  • drastic reduction of resonance in the surround and non linearities in the magnetic circuit which are responsible for blurring the stereo image.

In the Part 3 we will explore the Bass section of the Sopra.
Posted in: Focal   0 Comments

Focal Sopra- A peek behind the scenes

Posted by MD on 8 February 2016
As a lead up to our Special Focal/Naim Event on the 20th Feb, this is the first installment in a series of blogs which will give some insight into the design elements that give Sopra its unique look and sound. In this installment we discuss the High Frequency section.  In the Utopia Series Loudspeaker, Focal have created a flagship range, globally recognised, but out of the reach of many consumers. The Sopra is an exercise in passing down the new technologies inspired by what they have learned from the development of the Utopia III in the creation of a Loudspeaker with spectacular performance but at a more affordable price.

 

Introducing the Sopra Tweeter

 

 

The tweeter remains central to the design of the Sopra, it is the "eye" of the product that captures the eye of the onlooker. Its positioning is not just aesthetic, it is highly critical to the sound as it predetermines the speaker's spatiality, what Focal call "Focus Time".

WHY BERYLLIUM?

Due to its incredible rigidity, Beryllium represents the ultimate material for a tweeter dome. Focal, after two years of research and development, produced a world first: a pure Beryllium inverted dome, able to cover more than five octaves (1000Hz 40kHz). You may ask yourself, why strive for an extended response at 40kHz, if the human ear can only hear up to 20kHz? If you can extend frequency response, you will improve the perception of transients and other micro details. As well, the linearity of the speaker's response curve is mainly a function of three opposite parameters: lightness, rigidity and damping. To this day, Beryllium is the only material which permits a joining of these three parameters. The result is a sound wave propagation three times faster than Titanium and two and a half times faster than Aluminum. In the end, the linearity of the frequency response curve, the acoustic transparency and the impulse response of the Beryllium tweeter are maximized and offer near-perfect sound.


WHY AN INVERTED DOME?

The inverted dome tweeter is perhaps the perfect transducer. This design permits very high-efficiency, precision and energy. The particular advantage of the inverted dome tweeter is the optimisation of the mechanical coupling between the voice coil and the dome.

 

 

     Conventional Positive Dome Tweeter                  Inverted Dome Tweeter

The voice coil is fixed at mid-height on the dome and uniformly moves the cone entire surface. The positive dome is only joined at its edge, causing it to be inactive beyond 16kHz for a flexible surface. The inverted dome directly radiates into the air, with maximum efficiency, which is translated by an extremely precise soundstage. The dome's response curve is clearly more linear than that of any positive dome. It provides better space dispersion and very low directivity, contrary to ribbon tweeters. The inverted dome tweeter offers unequalled dynamics, enabling sound engineers to very precisely control compression. The image precision (height, width and depth) is outstanding and makes the positioning of each element very easy, as well as allows one to exactly assess the reverb tails.


A NEW APPROACH TO TWEETER LOADING - INFINITE HORN LOADING (IHL)


The requirement for Sopra to be compact meant that as much of the cabinet as possible had to be used for the bass. The Focal Design team had to explore a new system for loading the tweeter. Their Beryllium tweeter features an incredibly light and extremely rigid dome. Its main limitation comes from the compression of air in the cavity behind it. To overcome this, the ideal would be to have a nearly infinite volume.

 

THE IHL SYSTEM


With the Utopia IAL 2 tweeter Focal  worked on improving the flow of the rear-directed wave from the dome. In Utopia III the tweeter has its own enclosure with a large volume to absorb the back wave very gently, as would an infinite space. With Sopra, the need for compactness meant they could not devote the necessary volume for this. So their thinking has led them to imagine a rear acoustic load on the tweeter that approaches the ideal by gradually absorbing the rear radiation. Located on the back of the tweeter a progressively damped horn-shaped duct evacuates smoothly the rear radiation of the dome and has the advantage of being the most effective solution in terms of compactness, thereby preserving internal volume for the bass section.


The rear of the Beryllium tweeter is loaded via a small cavity which is connected to the exterior of the enclosure by a horn. The inside of the horn is filled with a damping material. Thus, sound waves from the rear of the tweeter are delicately and gradually absorbed. Its acoustic impedance approaches zero so that no resistance alters the movement of the dome. This pushes definition to its maximum. Moreover, a lot of effort went into isolating the tweeter from any interference from vibrations. The injected polyurethane mono-bloc tweeter frame provides the optimal mass and damping in a reduced space.
Thus, the Focal design team were able to get the most out of the woofers to enhance bass performance while having an ideally-positioned tweeter, and all this in a reasonably-sized cabinet.

In our next installment we discus the Sopra's Mid-range section.

Posted in: Focal   0 Comments

4K TV and premature marketing

Posted by MD on 1 November 2014

 

 

 

 

 

We all love to get excited about the "next new thing", and the latest "new thing" is undoubtedly 4K or now rebranded UHD. Unfortunately the industry has put the cart before the horse in many respects. UHD will eventually become mainstream but today it is probably only of real benefit at sizes of 80 inch and over. Future implementation of wider colour space and greater bit depth will lead to even greater benefits, but as of today it's only true advantage is resolution. If you buy a UHD TV today you are just buying and expensive upscaler. Your 4K content options are limited to a few streaming services but with our decrepit internet infrastructure the approximately 20Mbps bandwidth required to stream UHD means you will need to book your show a day or two in advance. The recently announced UHD Blu Ray player will be available late 2015, but until then upscaled SD & HD will have to suffice. My main gripe though is not the lack of content, but rather the lack of a firm set of standards, in particular something called REC2020. HD uses a standard called REC709, this specifies things like frame rate, resolution, bit depth and colour space. REC2020 is a working standard which means it is still not fully cooked. The danger is that people buying UHD TVs today may not be able to utilise features implemented further downstream. In fact the recent release of the HDCP2.2 copy protection spec has already rendered any TV or Receiver sold up to this point redundant due to them being unable to handshake with any HDCP 2.2 compliant device and therefore unable to display UHD content. Our advice is to forget UHD for the moment  and buy the best 1080p HD equipment you can afford. If you have to have UHD then talk to a speacialist in order to get the best advice you can so that you can make an informed decision and then , proceed with caution......

Posted in: 4K   0 Comments

Storm Season is Here, Are you ready for it?

Posted by MD on 24 October 2014
Power Protection and Filtering by Thor Technologies and Isotek

Storm season is once again upon us with the weather bureau predicting a stormy week for NSW next week. While I do enjoy a good storm, I'm not so enamoured with the collateral damage of a nearby lightning strike.  Therefore the point of this blog post is two-fold,  firstly to save you the heartache that accompanies the destruction of your beloved Hifi/Home Theatre system by a wayward lightning bolt, and secondly to expose you to a new avenue for improving the performance of your system.

There are two main objectives of a good quality power protection system. The first and most obvious, is protection, to stop your precious audio and video equipment from being turned into an expensive pile of molten carbon and plastic. The second, and less considered, is power filtration, to improve the quality of the power being fed to your gear. Power is the first input to any home entertainment system; it flows through the system, used by each component in turn to create the signal that moves the speakers’ drive units and delivers the pixels on the screen. What we see and hear is fashioned from, and by, mains electricity – it’s the ‘raw material’ from which the ‘art’ is created. Your musical or cinematic enjoyment will be reduced by mains noise contamination.

Let's take a closer look at the how's and why of 'Protection' and 'Filtration':


Power Quality

Power surges and spikes are the most common source of damage to electrical devices. A large majority of all electronic failures are power related. Faulty microprocessors, blown power supplies, damaged main or secondary boards and cumulative damage over time are some of the most common problems experienced. Nothing is more frustrating than having several thousand dollars worth of equipment destroyed in a matter of nanoseconds. While external factors such as thunderstorms or car accidents are the most obvious sources of power surges, many spikes can also originate from inside your home. For example, the spikes, surges and noise resulting from washing machines changing cycles, air conditioners, microwaves, fridges and printers will affect everything on that circuit.


Protection

Surge protectors are designed to limit excess voltage by blocking unwanted spikes above a certain threshold. A voltage spike may not immediately break your equipment but it could cause them to wear down over time by putting extra strain on the internal components. The clamping voltage determines the maximum point at which the surge protector will divert damaging voltage away from the protected line. In Australia, 240V is the expected voltage, a clamping voltage as close to this mark is ideal to protect electrical equipment from power surges. Depending on the size of the power supply, you will start to see smoke coming out of the back of an appliance at around 280/290V. Given that the industry standard for clamping voltage is between 680 to 710V for most surge protectors, this means that the majority of surge protection devices on the market won't stop damage to your equipment.

Joules is the measurement of absorption of a surge protective product. If Joules is likened to a sponge, the bigger the sponge, the more it can absorb and the better the power protective product. Joules are sacrificial; they cannot regenerate or be used again so once used up, the device can no longer absorb any excess energy. This can be catastrophic for protection on 'big ticket items' as the power protector is no longer a 'protector' it is effectively turned into a basic power strip. As power boards commonly sit behind cabinets, shelves or under desks however, unfortunately it is not commonplace for a board to tell you it is no longer protecting. Thor's Power Check Technology is unique and is critical to protecting any connected equipment. Thor's Power Check Technology shuts off a circuit automatically once the surge protection properties are used up, instantly alerting the user that the board needs to be replaced.

Filtering & Conditioning

Power line noise is a natural by-product of the distribution and use of electrical power. It is present in every electrical circuit and can pose huge problems with performance, reliability and longevity of any digitally sensitive circuit. Let's throw a few analogies around, who doesn't love a good analogy. A high performance sports car will not perform to it's maximum unless it is run on the very best available fuel. It can have gold plated fuel lines, platinum spark plugs and a state of the art fuel pumping system, but if the fuel tank is full of vegetable oil the performance potential will never be realised. Similarly, your HiFi system is unable to function to it's maximum potential because the fuel supplied to it from the mains is contaminated. HiFi source components are very sensitive to electrical pollution because the audio signals they process are at a very low voltage, and this signal must be amplified in order to drive the speakers. This causes a cascade effect within the electronic circuitry, resulting in a polluted amplified signal.

There are a number of benefits you will realise from a good power conditioner:

•Improved front to back layering and an extended and involving soundstage
•Effortlessly natural and open sound and far more 3D vocal image
•More attack and definition on the instruments and a Vanishingly quiet noise floor.
•Greater overlaying of harmonies, textures and detail
•Greater focus and bass articulation


With the above points in mind we have chosen two particular brands to fill out our power protection and filtering portfolio:

Thor- Thor make a great, affordable range of power protection and conditioning products for all budgets and applications. If you have unreliable power quality or are in a lightning-strike prone area, then there is a Thor product for you. Thor Technologies is 100% Australian and proud of it. All research, development and engineering is undertaken in Australia, even today their hardwired range is still 100% manufactured here. They really stand behind the products they sell, and all products are designed specifically for australian conditions and have a clamping voltage of 275V. You can rest assured that A Thor product will catch the spike and stop it before the smoke gets out, guaranteed. Check out their website, give us a call or drop into the store to learn more.

 

 

Isotek- Where Thor is a product for everyone, the butcher, the baker and the candlestick maker, Isotek build more esoteric products, aimed at the purist audiophile. Isotek's primary focus is on improving sound quality, their products are more about chasing the ultimate in audio performance, power protection is an added bonus. They claim to deliver the world’s best power cleaning solutions for lovers of high-quality sound. All Isotek products are designed and hand crafted in the UK. Check out their website, give us a call or drop into the store to learn more.

 

Drop by the store and check out your Power Protection and Filtration options.

Posted in: Power protection and filtration   0 Comments

Vienna Acoustic's Baby Beethoven Grand SE Now Playing.

Posted by Nathan on 17 September 2014
Vienna Acoustic's Baby Beethoven Grand SE Now Playing.
The most recent addition to the Vienna Acoustics Concert Grand Series, the Baby Beethoven Grand Symphony Edition is now gracing our hi-fi room. The BBGSE's (for short) combine a very open and wide sound-stage, incredible mid-range detail and a super fast and tight low frequency response that extends to levels normally associated with much larger speakers. But they don't just sound stunning - they look stunning too. The wonderful Craftsmanship of the Italian made cabinetry (which are lovingly turned into loudspeakers in Vienna - not china) is rarely found at this price-point. For those perhaps wishing for a smaller, sexier (and slightly smoother sounding) alternative to the B&W CM10's, I'd suggest coming in for a demo!
Posted in: Vienna Acoustics speakers hi-fi   0 Comments
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Focal Sopra Part 2- The Obsession with Midrange

Feb 15 2016

Welcome to our second installment on the innovative technologies employed in the new Focal Sopr...

Focal Sopra- A peek behind the scenes

Feb 08 2016
As a lead up to our Special Focal/Naim Event on the 20th Feb, this is the first installment in a s...

4K TV and premature marketing

Nov 01 2014
          We all love to get excited about t...

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