Focal stands out among others due to its strong scientific and technical potential. Those situations where most manufacturers reach a dead end, for Focal engineers are just a reason to think carefully and try to find a solution where no one has yet looked for it. The new driver technology for headphones, which the company announced some time ago, turned out to be an improved dynamic driver. It would seem, what else can be done with the headphone speaker to improve its sound? Moreover, the most famous manufacturers have been working on this task for decades, and who else, if not them, can achieve the highest results in the production of dynamic emitters.
It so happens that not a single manufacturer has yet been able to make a completely open headphone speaker. But Focal engineers did it. Although after four years of experimentation and work on production technology. Of course, they did not change the principle of operation of the dynamic emitter; accordingly, we can say that the main know-how lies in the selection of materials and methods of manufacturing parts. After all, all other manufacturers failed to cope with the task only because they did not have the technology to produce parts of such light weight and such high geometric accuracy. But let’s first figure out what the Focal engineers didn’t like about the conventional headphone speaker, and in what form they reinvented it.
It is customary to present top-level equipment in such a way that the buyer does not doubt its class for a second. Therefore, as a rule, the show begins with packaging. What kind of cases have I seen: designer, safe-like, made of expensive and pretentious materials… I thought I’d see something like that now, but the container for headphones with the price tag of a slightly used car was a black box made of thick cardboard, covered with “eco-leather” and stitched red thread – very good quality, but emphatically laconic.
Inside it is not just the result of four years of work by Focal engineers. This is an attempt to make perhaps the most technologically advanced headphones to date. The intrigue is further enhanced by the fact that a company that does not have many years of experience in designing such products has undertaken to achieve such an ambitious goal.
A traditional dynamic headphone driver has a plastic basket with a flat magnet. It is approximately the size of a ruble coin, and around it is a voice coil and a diaphragm attached to it; curly ribs at the edges of the diaphragm give them flexibility, acting as a suspension. This formula is simple and unchanged for the vast majority of dynamic drivers used in headphones. The diaphragm is usually made of mylar or similar plastic, which is lightweight and sufficiently rigid. The surface of the diaphragm can be metallized, for example, by sputtering titanium, but more often it has its original appearance.
The most important thing is that the back side of a regular speaker is always damped by an acoustic filter. This may be a layer of non-woven material covering the holes in the basket or a calibrated hole in the center of the magnet, limiting the flow of air from under the diaphragm. Without using an acoustic filter, it is impossible to properly configure the speaker. Try to undampen the headphone driver, and its more or less flat frequency response will turn into one large mid-frequency peak with a sharp decline in the low-frequency and high-frequency regions. And if you make the music louder, the coil will fly out of the working area and the speaker will fail. Acoustic filters that dampen the speaker help control the movement of the diaphragm and obtain a desired frequency response shape.
But why is damping bad then? Firstly, because when the diaphragm moves forward and backward, it is loaded differently, and secondly, any damping limits the freedom of movement as such and leads to a compression effect. Compression manifests itself in the loss of detail at low volumes, the inability to provide good macrodynamics and a truly open, wide stage. In short, listening to a speaker with damping is like driving a car without releasing the handbrake all the way. What difference does it make whether the car does not drive at all or drives with difficulty? Even if you slow down a little, the car will not be able to do what it is capable of with the brake fully released.
In an attempt to eliminate this problem, Focal engineers decided to use the speaker system’s tweeter as a model. As you know, in Utopia and Sopra acoustics the tweeter is completely dedamped, and its rear side emits sound waves into the open space behind the acoustics. A similar approach was implemented when creating new headphones. Moreover, the design and materials of the speaker are in many ways similar to those usually used in tweeters. For example, Utopia headphones are equipped with a beryllium diaphragm. This material has high rigidity and strength with extremely low weight. As a result, it is possible to make an extremely thin and light diaphragm from it, significantly superior to mylar in mechanical characteristics, but at the same time comparable to it in weight.
During the process of making the cone, it turned out that Focal’s usual concave dome headphone shape would not work because the driver was too close to the ear, and this shape would create dispersion problems. During the research, the developers came to the so-called M-shape: near the suspension, the diffuser has the profile of a concave dome, but closer to the center it turns into a traditional convex dome.
The suspension looks quite traditional for large speakers used in acoustics. In headphones, this approach is usually not practiced due to the inability to provide sufficiently low weight and high elasticity. Using synthetic NBR rubber and the latest production technologies, Focal developers managed to achieve suitable performance. To do this, we had to reduce the thickness of the suspension to 70 microns – this is approximately equal to the thickness of a human hair.
The voice coil is the third component of the moving system, the high mass of which would negate all the advantages of the diffuser and suspension. To achieve a low weight reel, Focal engineers did the literally impossible, depriving it of any kind of frame. The coil in the Utopia speaker is a single layer of copper wire, the turns of which are simply glued to one another. The height of the coil is 4.4 mm and the diameter is 25 mm! As a result, the total mass of the moving system of the Utopia speakers was only 135 mg.
Reducing the overall mass of the moving system was one of the main goals, since mass is the most important factor affecting sound quality. The lighter the moving system, the higher the acceleration with which the emitter diffuser can move. Combined with its extreme rigidity and non-limiting elastic suspension, this allows for excellent macro- and micro-dynamics, excellent attack and precise impulse processing – everything that makes music sound natural and expressive.
In order to accelerate the diffuser even better and ensure its rapid response to the slightest electrical impulses, a powerful magnet was needed. In the dynamics of Utopia headphones it is made in the form of two massive rings located outside and inside the voice coil. At the same time, a large hole in the center of the magnetic system allows air to be freely removed when the diffuser moves backwards. For obvious reasons, the earcups are also completely open; they do not have acoustic filters either on the back or inside. They are covered only by protective grilles and nets that are free for air to pass through.
The headphone speakers are quite miniature in size and are manufactured with precision precision. However, even they have some variation in parameters within one production batch. To ensure that both speakers in the headphones work identically, the drivers are first measured on a Klippel complex, after which they look at the data obtained and select pairs that are as close as possible to each other.
At the presentation of the headphones, Focal Marketing Director Nicolas Debard said that at first engineers spent a long time comparing headphones from different manufacturers. It is important that this comparison was not limited to only an analysis of the operation of the emitters. The developers took into account many points that affect ergonomics. “The heads of different peoples can vary greatly in shape and size,” said Monsieur Debar. “We took these features into account, and this headphone design will fit almost any head.”
Due to the fact that the headphone cable is Y-shaped and there is no internal wiring in the headband, you could experiment with the design as you wish. So the developers decided to make an extremely large adjustment range so that the headphones would suit everyone without exception.
The cup holders are made of carbon. They look good, lighten the structure and are highly durable. The mobility of the cups is ensured by the ability to rotate the holders around an axis at the junction of their entrance to the headband. This solution is usually used in professional headphones, but it is extremely rare in home headphones.
The headband and ear pads are made of genuine leather with perforations, providing the surface with “breathable” properties. The headphones adapt really well to the shape of your head and sit quite comfortably. The open design and large, wraparound ear pads in perforated leather provide comfort.
You can sit with headphones on for as long as you like. The only not very pleasant moment is being overweight. Focal Utopia, with all its open and airy design made of mesh with ultra-light carbon parts, still weighs like a real High End – almost half a kilo.
The included cable was selected according to its electrical characteristics. It has a linear capacitance of 70 pF and a resistance of only 0.09 ohms per meter. The connection to the amplifier is 6.3 mm in size from Neutrik, and the headphones are connected to two-pole Lemo connectors.