CHARIO ACADEMY SERENDIPITY
Academy Serendipity, despite being over ten years old, not only remains in Chario's offering, but is still at its peak. This speaker design is one of a kind, although it traces back to Chario's earlier references, the Academy Millennium Grand speakers. According to the manufacturer, Serendipity is the culmination of experience and assumptions collected from the very beginning of the company's existence, i.e. since 1975. The greatest acoustic value is hidden in a special configuration that cannot be identified only with the number of speakers. and their different types, but with the way they interact outside of the typical "multipath" pattern.
The body looks like a massive wooden stave, but this is only partially.
Thus, the side and top walls are partly made of boards, while the front, rear and internal reinforcement are made of fiberboard. There are many of them, especially in the subwoofer section, where there is a lot of energy left for damping, while in the rest they act as partitions, creating independent acoustic chambers operating in different subranges. The whole structure is actually divided into two parts, more or less equal in height. At the bottom is the subwoofer section, and at the top are the other four drivers. Chario does not overestimate the role of natural wood in achieving a natural sound, all the more adhering to the idea of giving speakers the role of "instruments"; the column should face, and not play - these are different things. The wood, however, has good mechanical parameters, and most importantly ... treated in this way, it looks beautiful.
Five lane for specific purposes
A five-party agreement is rare. Even if we add nuances and, taking into account some assumptions, agree that this is a four-and-a-half-way system (which will complicate the analysis even more ...), we are dealing with a design that goes far beyond the schemes used by other manufacturers . The creation of multiband circuits is forced by the inability of individual loudspeakers - or even pairs of different types of drivers (in two-way circuits) - to create a loudspeaker device that will simultaneously provide wide bandwidth, high power and low distortion. But division into three ranges - conditionally called bass, midrange and treble - is enough to achieve almost any basic parameters (speakers intended for home use). Further expansion may be due to the intention to achieve some specific sonic characteristics and properties. This is exactly how it works.
The extensive Serendipity speaker system is used not only to optimize the processing of individual sub-ranges of the acoustic range by specialized transducers, but also, paradoxically, to use the "side" effects resulting from the use of multi-band systems, which are considered harmful to other manufacturers and are minimized to the maximum. possible degree. The Serendipity constructor moves in the exact opposite direction to a constructor such as Cabas, who, with the help of concentric systems, is trying to achieve the effect of a "pulsating ball", a coherent source of all frequencies, radiating a similar characteristic at the widest possible angle in each plane (which is the goal of the concentric arrangement all converters). Displacement of transducers from each other leads to a change in characteristics outside the main axis (especially in the vertical plane in which this displacement occurs). Even if these attenuations appear on characteristics and axes that extend beyond the listening position, the waves traveling in these directions reflected off the walls of the room will also reach the listener and will burden the perception of the tonal balance of the entire image. . Therefore, according to most manufacturers, it is important to maintain a relatively stable, depending on the frequency, the so-called force response.
On the other hand, these potential attenuations can be considered as a good opportunity to reduce the amplitude of the reflected waves, that is, to reduce the reflections and their contribution to the creation of the image at the listening position. Looking at Serendipity, we see no obvious "anomalies" in the speaker system. The tweeter is located close to the midrange, the one next to the second midrange (filtered a little lower), which, in turn, is directly adjacent to the bass. However, for fairly short mid-frequency waves, which will be the crossover frequencies here, even such distances between the transducers mean that at angles of several degrees, and even more so - several tens, deep attenuations appear on the characteristics. Their width depends on the steepness of the slopes of the characteristics of the individual sections, which are closely related to how the speakers work together.
Here comes another piece of the puzzle, namely the use of soft filtering. The next thing is to set the crossover frequency close to each other - between the bass and a pair of midrange woofers is about 400 Hz, and between the midrange (more filtered) and the tweeter - below 2 kHz. In addition, there is cooperation between a pair of midrange drivers (otherwise filtered, but their characteristics lie close to each other over a very wide range, and the lower filtered midrange also interacts with the tweeter) and, finally, we have a lot of overlapping and overlapping characteristics. It is quite difficult to determine the expected (not necessarily linear) characteristics of the constructor only along the main axis in such a situation, and it is impossible to achieve stability at large angles. However, designer Chario wanted to achieve just such an effect - he calls it "decorulation": attenuation of radiation from the main axis, in a vertical plane, in order to reduce reflections from the floor and ceiling.
Woofer Configuration
Another specific solution still related to reflection control is the configuration of the loudspeakers in the subwoofer range. The section, which the manufacturer calls the sub, is located at the very bottom of the structure. The point here is not in its other features (which will be discussed later), but in the fact that the radiation source is located just above the floor (we can only see the shaded "windows" of the basement, facade and sidewalls). In turn, the woofer is left by the company from the floor to the maximum, the curve resembles the well-known so-called. isophonic curves, but this does not follow from the (too) simple conclusion that we must "correct" the properties of our hearing in this way (which we do not correct with any hearing aids when listening to natural sounds and live music). The need for this correction Chario derives from the various conditions in which we listen to music - live and at home, from a pair of speakers. When listening live, direct and reflected waves reach us, which together create a natural spectacle. There are also reflections in the listening room, but they are harmful (and therefore Chario reduces them using the methods described above), because. create completely different effects, not reproducing the acoustic conditions of the recording at all, but resulting from the acoustic conditions of the listening room. Aspects of the original space of the recording are encoded in the sound played back through the loudspeakers in a straight traveling wave (eg reverberation). Unfortunately, they come only from the side of the loudspeakers, and even phase shifts that can expand and deepen our space will not completely correct the situation. According to Chario's research, our perception focuses too much on mid frequencies, which therefore need to be attenuated to some extent in order to get the most naturalness possible of the entire sound event, both in tonal and spatial domains.
When one pulls, the other pushes
The design of the Serendipity subwoofer section is a chapter in itself. Here we are faced with a push-pull system, rarely used today (in a somewhat broader sense, also called compound or isobaric). This is a pair of woofers connected mechanically “diaphragm to diaphragm” and electrically in such a way that their diaphragms move in the same direction (relative to the body, not individual baskets). Therefore, these dynamics do not compress the air closed between themselves (hence the name isobaric), but move it. To do this, if they have exactly the same structure and the turns are wound in the same direction, they must be connected in opposite (to each other) polarities (by marking their ends) so that they finally work in the same phase (when the coil is deepened one) into the magnetic system, the coil of the other goes out). Hence the name push-pull - when one speaker "pulls", the other "pushes", but they still work in the same direction. Another variation on this arrangement is the magnet-to-magnet arrangement, and another that works with essentially the same sonic effect is the arrangement where the speakers are placed one behind the other in the same direction (outer magnet adjacent to the magnet). inner aperture). Then the speakers should be connected in the same polarity - such a system, although still “isobaric”, should no longer be called push-pull, but, possibly, compound.
I will write about minor differences between these options at the end, but what is the main advantage of this system? At first glance, this setting may seem to add up the pressure generated by both speakers. But not at all - yes, such a system has twice the power (it is taken by two coils, not one), but it is half as effective (the second “portion” of power supplied to the second loudspeaker does not increase pressure). So why do we need such an energy inefficient solution? The use of two drivers in a push-pull (composite, isobaric) system creates a kind of one driver with different parameters. Assuming that it consists of two identical transducers, Vas will be halved and fs will not increase, because we have twice as much vibrating mass; Qts does not increase either, because we have a double "drive". Summa summarum, the use of a push-pull allows you to double the volume of the cabinet (many systems - including closed, bass-reflex, bandpass, but not transmission lines or horn cabinet) to obtain a certain characteristic, compared with using a single loudspeaker (o the same parameters, as with two-stroke loudspeakers).
Due to this, with a not so large volume (I remind you that the upper module serves other sections), we got a very low cutoff frequency (-6 dB at 20 Hz).
