Sonido feels itself committed towardsfullrange (one-way and quasi one-way) systems. This has a couple of reasons, but first we should go a little more into the matter.

When we first bumped into a relatively good one-way (fullrange) driver, we had to turn over our technical world view. We were confronted by such a musical coherence – a sort of self-evidency – as in live performances. However it was depressing but at the same time motivating to admit the blemishes of this driver: it was indisputably colored, with insufficient bass and also the high tones were sometimes dim, matt. Even so, such a suggestive livingness rushed from this sound which we could not transgress with a flick of the wrist.

KLANG+TON magazine test 2011/5

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Problems of the Multi-way systems

Whether we think about sequence of sounds in a composition or the sound waves of just one musical tone, we shortly realize: the fundamental substance, almost material of music is time – just like space is of sculptures and light is of painting. So it is easy to see, that a good sound reproduction device should handle time assertively.

The musical signal is an immensely complex process, which agrees to a persistent alteration of pressure: in fact it is continuously varying speed. It can only be broken up to frequency bands through mathematical abstraction. The musical sound is an elemental whole. The web of overtones can not be detached from the keynote without retribution, while it is a fundamental precondition in multi-way radiation. But why is it?

To judge a high-range separately is useless, because it is not likely that it will operate this way during a listening session. More likely it will -even during the display of a single fluting- together with the mid-range driver which has highly different transient (temporal) properties. However in the vicinity of the crossing frequency a so called overlap band produced, where irrespective of the overtones, both speakers can be heard. Unfortunately, even with the most supremely designed crossover, these sounds will only be in the same phase (thus coherent) on a discrete frequency. Accordingly they will slither in time, the dynamics will smear and the details become dim. Some crossover designs minimize this error, but than the problems show themselves in the global phase response (an unsolvable mathematical necessity). So it is impertinence to have quality parts, if we temporally tumble the musical structure.

Another problem is the radiation from different places, which also adds to the phase-footing problems. Furthermore, at least one crossing frequency, will likely to be in the band, somewhere between 400 Hz and 6 kHz, most informative in hearing.

Through these problems we present to our brain's auditory center, a substantial amount of forced labor (with all good intent of course), which must reconstruct the right information from the stimulus tumbled in phase and ring off time. During listening it causes a premature feeling of tiredness, bluntness. Because these time distortions and strongly nonlinear type, our brain is not capable of salvaging all the important information. Because of this, in a multi-way system a typical electronic taste gets into the sounding, which we in the lack of reference not recognize most of the time.

Is the fullrange driver an answer?

It often proves to be scarce to just list the theoretical benefits of fullrange loudspeakers. Coloration and band bounding are the most commonly referred problems. However we must know, that these phenomena does not spawn from theoretical barriers.

Some also disapprove the directionality. According to our view this can even be turned to a virtue, if with an appropriately shaped membrane it made even. Thereby the room reflexions will drop off, and an accurate sound free of resonant overtones can be generated.

Getting rid of coloration is a bit harder task. It's main cause is that higher tones get out to the edge of the relatively large radiation surface, and than they bounce back (annularly modal partial vibration). Experience showed, that the effective radiating surface of a good fullrange driver should decrease with the increase of frequency. As we raise the frequency less and less kinetic energy is transferred from the voice coil to the edge of the membrane. In practice this can be achieved, by making the vicinity of the membrane neck rigid in the case of higher voices, but with the increase of radius they are partially absorbed in the material of the membrane. With this in mind -and with lots of abortive experiments of course- a kind of material and geometry can be produced, which keeps the waves from bouncing back from the edge. This way we get a special, split parametric radiation surface which is powered by a single mover.

To achieve good high-tone transfer, we need a very strong mover, and minimal moving mass. The entire moving mass of the Sonido SFR144 for example is less than 5 grams, which accelerates and decelerates with the help of 7 T*m (teslameter). (For comparison: a good quality mid-range driver with the same size, has at least 7 grams of moving mass, but the majority is even heavier. Their force factor often hardly reaches 3 T*m.) With this outstanding force-factor/mass ratio, we elevate the detailing capabilities into the world of static drivers, catching the advantages of point-like radiation, and at the same time ruling out the disadvantages of the coupling transformer and the big radiation surface.

Why horn?

In case of a driver of such strength we can't apply the “air spring” concept the conventional box constructions, because of the low Q value. But they can be exceedingly loaded with a bass horn. The horns are the most efficient couplers: they couple the energy transmitted with the driver with small diaphragm displacement, thereby the problems from inertia are lesser, and not the least this results in smaller distortion and excellent dynamics.

Upon mentioning horn speakers, many reply: -If its that good, why is it not widespread? The main reason is that the conventional sizing formulas are just plainly not good (they were adopted for an extremely simplified case), and because the dimensions are generally large, in reality it is hard to eliminate duct and box resonances. On top of that, the realization is expensive.

After an immense amount of research and development, with rewarding technology and sophisticated design we bravely claim to have achieved a highly uncolored bass-horn loaded sounding, additionally on a decent price.

In defiance of the long standing design stock phrases by now we approach the question of engrossment into a music's temporal structure or rather into the music itself, from this viewpoint. The result is an extraordinarily coherent, airy and finely structured sounding with clean-cut space representation. This combines with the astonishing dynamic potential of the horn which operates in the low registers. The transparency can be contrasted with the “difficult to drive” static panels, but with a more assertive space representation and bandwidth. Thereby we can get into a really close relation with the music, and it's real, fine structure.

The significance of running in

Running in is important with any driver. Spider and the surround “brakes in”, its permissiveness becomes uniform. This however in the case of paper cones, and especially with fullrange drivers is particularly important procedure. As the cone's fiber structure settles, measurable changes occur in the response. This is caused by the reduction of the partian vibrations, and the change in their mode: the inner attenuation increases. Thereby the runned in cone does not radiates the same way on it's whole surface, but the high frequencies are beneficially absorbed towards the edge. With that forms a divided parameter radiation, which excellently nears the requirement of point-like source.