IT202000022627A1 - TRANSPORTABLE EQUIPMENT FOR HIGH YIELD ACOUSTIC REINFORCEMENT OF AUDIOFREQUENCY SIGNALS - Google Patents

Description

DESCRIPTION of the invention with TITLE:

?Transportable apparatus for the high-performance acoustic reinforcement of audio-frequency signals?

DESCRIPTION

The finding of the present invention ranks among the transportable apparatus for reinforcing sound signals, more commonly referred to as loudspeakers or amplifiers, and more? specifically refers to that field of acoustic diffusion equipment designed for high efficiency, i.e. the possibility? to reproduce a non-programmed excursion signal (high dynamic excursion) on a very extended frequency spectrum, especially at the lowest frequencies? low what how? known require greater quantity? of energy, being able to produce a considerable volume of power for a certain period of time without having to resort to the use of the electrical network and at the same time being able to feed a large number of external and internal devices suitable for processing the signal in question, with a wide autonomy from the mains and easy to transport.

The technical field of use of the present invention differs from that of the devices designed for the reproduction of ?sound programs? that is, that of reproduction, to a degree of fidelity? qualitative compromise between spectral extension and reproducible volume, of radio-broadcast signals, physical or digital media called ?liquids? containing recordings of musical works, excerpts, songs, and, in a general sense, of recorded signals, since the same recording support imposes limits of dynamic range which is always controlled and ? therefore it is possible to reproduce these signals - at a volume albeit relatively low - on a frequency spectrum more? selective where a qualitatively non-demanding listening is necessary: what? can? be obtained by means of loudspeakers of very small dimensions (practically pocketable), an objective that already? find satisfaction thanks to found pre-existing, gi? disclosed and discussed in other patents, which allow listening to such sound material also by means of a direct connection via cable or transmission over the air (in Frequency Modulation or Bluetooth protocol). Playback on these devices can also take place in places not served by the electricity grid and there? ? possible by means of a built-in accumulator (hereinafter referred to as ?energy group?) which, after recharging, allows its use for the duration of a given period of time.

Does the invention discussed in the present invention instead find greater ? but not exclusive? use in live entertainment and in the amplification of electric musical instruments, guaranteeing correct reproduction of signals coming from electric chordophones such as guitars, basses, mandolins but also electronic instruments which in fact reproduce in turn signals recorded for concertation use or produced through electronic synthesis, as well as? the voice.

Since their original invention, amplifiers for electric musical instruments have been considered an essential complement to certain instruments which would otherwise be mute due to their physical characteristics, such as solid-case chordophones (electric guitars and basses) or electronically-voiced keyboards. In the case of mechanical instruments, cio? those equipped with metal strings or other types of means which, by vibrating, interfere with the magnetic field generated by a transducer capable of bringing the sound signal back into electrical form, the amplifier in question will have to? guarantee satisfactory amplification of a signal with strong dynamic excursions, being able to reproduce it at a sustained volume so that the sound can be appreciated in public and crowded places, with a frequency response suitable for the entire spectrum of the signal so how ? transduced by the instrument (fidelity on the whole useful bandwidth).

Instruments capable of generating high frequencies require loudspeakers and amplifier stages capable of reproducing these frequencies correctly and with a fairly wide emission angle, due to the rigid directivity? with which these frequency bands are mechanically reproduced, while those instruments dedicated to the production of low frequencies, so? as even those instruments that produce signals extended over the entire audible band require, in addition to very performing and robust power amplification stages, also very large loudspeakers capable of moving large masses of air and consequently the loudspeakers themselves will become large enough to being able to accommodate both said loudspeakers and a volume of air suitable for the correct functioning of these transduction components.

Musical instrument amplifiers have therefore always been characterized, in addition to the need of an external electrical network supply, even from a considerable size, that of the entire box containing the loudspeakers dedicated to reproduction and sometimes also the signal amplification stages useful for driving them; but also by a considerable weight, since the vibrations at frequencies pi? low to what? subjected to the acoustic system they are capable of displacing both the surrounding air (for the purposes of sound production) and involuntarily the speaker itself, thus requiring a suitable counterweight or even suitable fixing means to the support surface. Are the means known? effective for the control of these "parasitic" vibrations: a correct sizing of the case, a correct choice of construction materials and their thickness, the use of reinforcements inside the case and of other sound-absorbing materials in order to better distribute the kinetic forces on the walls by reducing the amount? of sympathetic vibrations (these, if present, would actually affect the quality of the sound performance and therefore need to be reduced to a minimum), and possibly the use of mechanical suspensions, counterweights and other resolution techniques.

With the passage of time and with the progress of available technologies, the request for amplification systems of ever smaller dimensions and weight have had to lead to considerable advantages for all those musicians who have the need to to move more easily, on foot or by means (public or private) and therefore often with little space available, to be able to perform anywhere without the need to of a connection to the electricity network, albeit so far at the expense: of a reproduction of the acoustic spectrum extended up to the needs? of the instrument that must be amplified (in this case for very low frequencies); from the request for sufficient volume to be able to perform in the presence of other instruments with an equivalent volume of sound; from portability? which finds disadvantage in a correct volumetric and weight sizing of the speaker, as well as? having to give up the possibility? to process the signal produced by their instrument through other electronic devices, called ?effect pedals?, the purpose of which is? to distort and manipulate the sound signal cos? generated before it is played by the amplification equipment. Said effect pedals require an adequate power supply for their operation, supplied through alkaline batteries placed inside each single pedal (known for having limited autonomy) or, so, as for the amplifier, by means of a mains supply.

The main purpose of the following invention therefore consists in providing an apparatus able to allow every musician the possibility to perform in any place and on any occasion, being able to produce a listening volume useful for concerting with instruments already? naturally equipped with high volumes of sound, such as drums for example. with a technical complement as portable as satisfactory from the point of view of quality? of the sound output. as for a large number of effect pedals arranged by the musician to his liking.

Another object of the following invention consists in guaranteeing autonomy from the mains for a reasonable number of hours, extending the autonomy of the apparatus also to a vast series of external devices useful for the production and processing of sound and more.

Another purpose of the following invention is to ensure maximum portability? of the apparatus in question, reducing its weight and volumetric footprint without affecting the aforementioned quality? surrender: in this sense, the apparatus? equipped with lifting and transport means which, at the same time, can be used for fixing on various surfaces (from floors of all types to mechanical supports for incorporating the apparatus, or more apparatuses, with other auxiliary equipment ).

A final object of the following invention is to expand the possibilities? techniques of the apparatus proposed to the pi? various paths of signal processing and a pi? cutting-edge features maintaining the characteristics of size, weight and portability? of the apparatus in its primordial version: through plug-in interface cards? Is it possible to implement additional features? such as processors, effects, computer controls and sensors of various kinds.

These ? how others? purposes can be achieved with the transportable apparatus for the high-performance acoustic reinforcement of audio-frequency signals described below, illustrated in the attached figures, without precluding further improvements within the scope of the present invention:

FIG.1 - lateral exploded view of the apparatus in its essential parts

FIG.2 - transparent view of the case (10) only and of the internal reinforcement structure made of strips (21) of wood or polymeric material

FIG.3 - transparent view of the case, complete with amplification circuits (32), heat sink (42), voltage monitoring circuit (33), controls and connections exposed on the walls

FIG.4 - transparency view of the same case (10) on the obverse side

FIG.5 - isometric detail of the amplifier (32) and dissipator (41) assembly FIG.6 - view of the apparatus equipped with effect pedal (62) and recharge device (61) FIG.7 ? side view from below, where? visible the passive radiator (12), the heat dissipation pin (421), the quick-connect handle (73), the Speakon power connector (161) and the relative toggle switch (71) between the internal amplifier line to the apparatus and a possible supply externally

FIG.8 ? block diagram of the entire electronic section that makes up the apparatus

FIG.9 ? isometric detail of the complementary fixing system of the quick-coupling handles

FIG.10 ? illustrative view of the fixing system of the apparatus on an adjustable support FIG.11 ? rear isometric view of the apparatus equipped with means of carrying on the shoulder (1102) and with fixing feet that can be adapted to any surface (1108)

FIG.12 - isometric view of the apparatus illustrated so far, complete with speaker protection grilles and pockets for inserting plug-in expansion cards

The measurements carried out on a first prototype of a complete apparatus made according to said drawings, having an overall volume of less than 27 cubic decimetres and a weight not exceeding 11 kg, in fact resulted in the production of a sound volume exceeding 90dB SPL (constant) at frequency of 24Hz with a harmonic distortion of 10% for at least three hours.

The construction, development and maintenance of this apparatus are very simple and possible at very low costs since the particular configuration of the passive radiator transcends the volumetric dimensioning of the diffuser a priori, proposing a more practical possibility? to tune the resonant frequency of the entire system construction already? completed; the cumbersome and efficient nature of the buffer battery which powers all the internal and external electronic devices is instead exploited as a counterweight useful for stabilizing the apparatus if assisted by suitable anchoring means to any type of surface; but even more is the simplicity evident? with which it is put into operation in the absence of connection to the mains: ? just place the little needed and connect a very limited number of cables (for the direct connection of the instrument only one is sufficient, for the connection of an effects pedal two signal cables and one power cable are required between the apparatus and the pedal) and, by lifting the ignition switch, the set-up ? ready for many hours of high-volume, wide-frequency performance.

The first problem that the inventor had to face? was to choose a design model of acoustic box that had a very reduced size and weight while maintaining, in fact, a satisfactory reproduction at the lowest frequencies? low. These, how? known, require a very large mass of air to move both outside the case, where the sound is reproduced, both internally, to counteract the physical forces at play on the loudspeaker. Both the infinite baffle model (or simply closed case) and the ventilated or reflex case require an internal volume of air proportionate to the lowest frequency. low to reproduce and the size of the speaker, resulting cos? of a size not very suitable for our needs.

In the case of the infinite baffle, the response to very low frequencies would have been limited, not very efficient and therefore not very adequate to expectations; a case ventilated (reflex) would be more? responsive in the aforementioned range, so as to require less power delivery from the amplifier, but the dimensions of the port would have led to a problem not only on the overall dimensions of the cabinet, but how? also known about design tolerances, due to the tuning of the port to the overall resonant frequency.

It was therefore decided to opt for the passive radiation sealed case (10) - illustrated in figure 1 without the side walls to be able to observe the inside - where at least one loudspeaker diaphragm of the electrodynamic type (11), hereinafter said active transducer, being driven by a power amplifier, acts on an air mass inside the case with the assistance of at least a second diaphragm, the so-called passive radiator (12) more? great. Is it possible to opt also for the sum of pi? passive radiators more? little ones.

Said passive radiator (12) seen from the outside is apparently identical to an electrodynamic loudspeaker if not for the total absence of the magnetic group, which on the active transducer we find composed of a magnet and a coil: not being controllable in any way, the passive radiator ? an inert body, but in the special configuration of the sealed case, this shares the same internal air load as the active transducer (11) and working in agreement with the latter produces an extension of the spectrum below the resonant frequency possible with only the active part (said frequency is the minimum that can be reproduced by the active transducer (11) and should be electronically filtered so as not to be reproduced by this transducer - under penalty of a malfunction of the vibrating system and a bad acoustic and mechanical response).

In the case of the passive radiator configuration, how? known, the resonant frequency of the entire system transcends the volumetric dimensioning of the case (10) to be delegated to the mass of the resonator diaphragm (the passive radiator 12): ? what? Is it possible to obtain a relatively very small case (10), with a volume of air lower than necessary and ? what? It is possible to tune the low frequency response simply by varying a small iron weight sample, firmly bolted to the dome located in the center of the vibrating diaphragm (121) of the resonator diaphragm.

The same case (10) now visible in figure 2, inside, ? reinforced with strips (21) in wood or polymeric material that run along the walls and branch out with precise distribution criteria, so as to distribute the kinetic forces and stabilize the apparatus when the vibrations reach the resonant frequency. They also have the task of locking in position some critical parts including the energy group (14) already? shown in figure 1, which will be? detailed below.

The case (10) can? be designed in the shape of a parallelepiped, cube, spheroid or wedge. Among these, the embodiment of the wedge offers the possibility of support on the floor surface in the immediate vicinity? of the musician standing or sitting. In this way the active diffuser (11), positioned on the inclined front wall (13), is always oriented towards the ears of the performer. On this wall (13), fixed to the rest of the case (10) by means of screws and therefore removable,? Is it possible to also foresee the presence of one or more? tweeters, active speakers for high frequencies (not shown) orbitally orientable, used after appropriate electronic filtering from low frequencies, if connected to the same power output as the main active transducer; alternatively, deriving a crossover output driving a power amplifier dedicated to high frequencies. This characteristic ? particularly versatile on the most embodiments? demanding from the point of view of the power produced, of the dimensions of the case (10) and of the diaphragms (11 and 12) as well as? by the presence of a greater number of them.

The active high frequency loudspeakers can be controlled by means of a rheostat and deactivated by means of a switch (SPST type switch) positioned on the subfrontal wall (18). Often a combined situation between the two is adopted, which allows the tweeter output to be attenuated to a minimum: here a switch mechanism will open? the output circuit completely, disabling the high frequency transducers. This particular rheostat-disconnector is often bulky and must therefore be easily located on one of the side walls of the apparatus.

The positioning of the passive radiators (12) can? be arranged on any wall. In the event that there are an even number of them, ? it is always appropriate that they are on opposing walls cos? to neutralize the kinetic forces that could lead the case (10) to shake and move with the vibrations pi? low.

In the pi? simple embodiment always illustrated in figure 1 only one passive radiator (12) ? positioned on the wall below the crate (10), pointed towards the floor. The passive speaker (12), as usual, consists of a vibrating membrane, in this case identical to that of a woofer but can? also be made by means of a flat panel suitably suspended with elastic material; said passive speaker (12) ? bound to a frame or basket, in the case of the traditional loudspeaker shape by means of a rubber, foam or cardboard suspension (on the larger external diameter, closest to the mouth of the case) and a fabric centering device (called spider ) on the smaller internal diameter, in the posterior position. These parts are substantially identical to those commonly found on any active loudspeaker (11) of the electrodynamic type.

The center of the passive radiator (12) known as the dome ? originally intended to accommodate the coil and to center it in its magnetic group: in the passive version ? replaced by a cap in polymeric or woody material on which ? It is possible to bolt on a weight standard of the weight necessary to tune the resonant frequency of the case (10), after construction and sealing is complete.

Since the internal volume of the case (10) and therefore the overall dimensions of the apparatus no longer represent? a problem, ? Was it appropriate to incorporate inside, fixed between the wooden strips (21) the energy group (14) consisting of one or more? capacious buffer batteries (141) connected in series, with the aim of reaching the overall voltage of 12 Volts.

Sar? it is necessary to adopt an energy group suitable for being confined in an enclosed space even if the apparatus is stored or transported in different positions. The batteries of the AGM type (or alternatively Lead-GEL) whose technology? referred to the category of completely sealed batteries, they can be mounted in any position and, apart from the ordinary recharge cycles, do not require any other type of maintenance.

A better choice, but more? expensive, ? represented by the Lithium-Iron-Phosphate batteries, much more? light and efficient: a battery of 1/5 of the weight of a Lead acid or AGM pu? deliver double the Ampere-hours and represents a more choice? eco-sustainable, considerably reducing the space occupied inside the apparatus.

The weight of said batteries (141) certainly contributes to the counterweight of the case (10), making it less susceptible to movements induced by vibrations at certain frequencies.

It was convenient to opt for a simple series of two nominal 6V batteries (141) in order to obtain an adequate power supply for all the circuits we will discuss shortly, especially those requiring a dual power supply ?, i.e. with the same voltage value for both positive and negative signs, with reference to the common earth potential.

Alternatively can? a single 12V battery supplying 18 or 22AH may be sufficient for a longer operating time in single power supply. In the case of the lithium ion battery, ? it is advisable to adopt a 35Ah one.

The energy group (14) ? permanently installed inside the case; ? It can be easily removed for immediate replacement by providing a suitably sized and watertight space inside the case (second cavity), accessible from the cover located on the rear wall (not shown).

As shown in figure 3, at one of the poles of the energy group (14) - for convenience, the negative - ? an on switch (31) of the entire system was connected, arranged on the subfront wall (18) of the case.

The driving of the active loudspeaker ? obtained by means of an amplifier stage (32) in class AB (which involves the best quality of reproduction but the greatest consumption of energy due to the continuous activity of the power transistors) or in class D (obtaining the maximum efficiency in of power, minimum energy consumption and minimum heat production at the expense of a satisfactory reproduction quality only at low frequencies), or even in class G or H, which allow rapid switching of the general power supply line according to of the power necessary for the reproduction of the signal, even if commonly these require more resolving forms? complex.

For testing the amplifier (32) in class AB ? The TDA7379 IC from ST Microelectronics was chosen, as it is designed to produce convenient power starting from only 12V supplied by the energy group. The integrated in question ? equipped with four outputs, but pu? in fact produce up to 38W at a frequency of 1kHz on each of the two pairs of outputs in Dual Bridge configuration with only 18V of direct current power supply (repetitive peak of 5A).

To be able to exploit the maximum power available on the integrated circuit? been so? selected a loudspeaker (11) equipped with two separate voice coils and suitable characteristics to produce a frequency response between 50 and 5000Hz.

Was it like this? selected a loudspeaker (11) of the double coil subwoofer type with a diameter of 165 millimeters with a total quality factor (QTS) suitable for the type of project. On each of its reels ? a pair of outputs of the integrated TDA7379 in Dual Bridge configuration was then connected.

To obtain the total 78W on both coils (112) of the small subwoofer (11) ? was it necessary to raise the primary voltage of 12V to 18V, therefore yes ? made convenient to introduce a further circuit called DC-DC converter (33), between the switch (31) connected to the battery (141) and the amplification stage (32) by means of the positive terminal. Said circuit (33), supplying a current sufficient to support the absorption peaks of the amplifier in question, is proved useful for raising the voltage of the battery (141) from the initial 12 Volts to 18 Volts, ensuring operation of all the electronics subordinate to it, including the amplifier (32) for an autonomy of at least three hours.

In the event that it is necessary to power amplifiers more? powerful, such as those in class D, G or H, the circuit (33) ? capable of raising the primary voltage from 12V up to 36V. In this case ? however, it is advisable to resize the project in its entirety: dimensions of the speakers, number of backup batteries and maximum tolerance of the current that can be supplied by the DC-DC converter.

Furthermore, the circuit (33) ? equipped with a numeric segment display (34), which can? be exposed on one of the walls of the case (10) so as to have a constant measurement of the level of charge when the apparatus ? up and running. In the figure we find it exposed on the upper wall (15), provided that it is not positioned too close to the of the energy group (14) for safety reasons: if the latter is too bulky, ? it is advisable to place the circuit (33) on the front inclined wall (13).

The display (34) located inside, when turned on to indicate the charge level, is visible outside the sealed case (10), by means of a transparent or translucent glass.

One or more? LEDs can be provided and displayed on the outside of the case (10): at a certain minimum voltage threshold supplied by the energy group, a microcontroller present on the circuit (33) will provide to turn on the LED communicating to the user the need? to timely recharge the device before it switches off, also avoiding damage to the energy group (remember that buffer batteries cannot remain completely discharged for a long time).

The back side of the integrated TDA7379 ? soaked in thermally conductive paste and fixed on a piece of aluminum bar (41) now visible in figure 4, called dissipator, in the form of a parallelepiped or on a profile with fins. This heat sink (41) carries one or more? threaded holes (female) (411).

On the wall (16) of the case, one or more? holes (412) of the same nominal diameter. A plurality? of pins (male) (42) are made from a solid round aluminum with the same thread; it is in turn soaked in thermally conductive paste and screwed onto the threaded seat of the dissipator (41), as illustrated in detail in figure 5, so that the head of the pin (421) is located outside the side wall (16) of the case (10) and that the dissipator (41) is inside: in this way ? It is possible to fix the dissipator (41) of the integrated on the wall (16) of the case and obtain the conduction of the heat produced during the operation towards the outside of the apparatus.

The assembly of the dissipator (41) must be foreseen as soon as possible. as far as possible from the rechargeable batteries (141), in order to avoid overheating of these beyond the permitted limit and consequent damage: generally however, the movement of air inside the case (10) induced by the loudspeakers (11) and (12 ) helps to drastically reduce the temperature of this space.

Looking at the detail of figure 5 ? visible the head of the pin (421) which is located outside pu? bring back a broach in the shape of a cut, of a Phillips cross, of a socket with an hexagonal head (allen wrench); can? be milled in the form of a hexagon to be screwed by means of a wrench, or, made in a round shape as per the drawing, it can? return to the center a hole more? smaller than the pin (by convention an M6) which is in turn threaded.

Through an additional M6 pin (423), a nut (424) and a lock nut (425) it will be? what? Is it possible to obtain a single block integral with the pin (42), so? to be able to screw it firmly onto the dissipator (41), being able to then remove the second pin and the two nuts as shown in the figure. Similarly it will happen for disassembly.

Is the switch (31) connected to the energy group (14) ? type SPDT (single way, two positions), as we said pu? have the center pin connected to the negative pole; the power amplifier (32) and the other electronic circuits connected to one of the two position pins (for convenience the other electronic circuits go into conduction with the energy group (14) if the switch (31) is activated towards the high) while on the other pin position the switch (31) can? having connected an external connector (35), exposed on the other side wall of the case (17). What? setting the switch (31) to the off position (down for convenience) will be? It is possible to have a direct connection with the poles of the energy unit (14) on the external connector (35).

The presence of a diode inside, will prevent? that an accidental inversion of the voltage connected to the poles of the connector (35) could damage the battery.

Can you? what? prepare the recharging of the batteries (14) by means of an intelligent device (61) visible in figure 6, optimized to manage different recharging phases and bring the energy group (14) back to its maximum state of charge in safety, without damaging it and without having to extract it from its location inside the case (10). Said device (61), self-ventilated, can? be equipped with charging voltage monitoring circuits.

The charging device (61) can? also be provided internally on the devices pi? big, as long as providing for adequate ventilation: in this case a small containment chamber (not shown) must be set up as a cavity? separate inside the case (10), cos? to be arranged on the external wall (17) of the apparatus a simple mini-VDE connector for connection to the electrical mains.

Inside this cavity? separate the further presence of a switching power supply for mains power render? the device usable in those situations in which a network supply is available.

On the devices pi? little ones ? convenient to arrange said recharging device (61) on the outside, avoiding the cavity? dedicated inside the case (10) and the ventilation ways necessary for heat dissipation.

The device (61) ? connected to the apparatus by means of a three-way connector, to distribute two separate conduction lines (more? common ground): will supply? in this way on the first line the intelligent recharge current for the batteries (141) and at the same time on the second line a 12V switching type power supply. Sar? what? Is it possible to use the full functionality? of the apparatus, excluding the batteries (141) as a power source during the recharging cycle. In this embodiment, the switch (31), in the recharging position, will put? operating the device by means of the power supply from the mains, in the meantime that the device recharges the energy group (14). In this case it will be necessary to integrate a second stand-by switch which deactivates all the acoustic diffusion functions, if the device is not? used in the recharging phase, or use a single switch with more? positions: 1) off, 2) recharging only, 3) on and, if connected to the mains, charging (with operation and recharging arranged for separate lines).

In any case, the intelligent recharging device (61) must first be connected to the electricity grid and then to the energy group with which it is connected. fed the whole apparatus, therefore during the connection to the mains the switch (31) must? be in the off position, otherwise the energy unit (14) could be damaged.

With the recharging device (61) inside the case, a micro-controlled circuit or a special switch must therefore also be provided which allows the batteries to be recharged only when the recharging device (61) is already in place. connected to the network.

The energy group (14) supplies power to all the circuits, internal or provided externally, useful for the operation of the apparatus: in addition to the power amp (32) based on the TDA7379 integrated circuit and the voltage ramp-up circuit (33) , which are capable of operating with a single voltage of 12V, we will find pre-amplification circuits and signal processing circuits supplied from the outside.

They have conventionally been illustrated in the form incorporated in the power amplifier (32) without excluding the possibility of different printed circuit boards.

These pre-amplification and processing circuits can require two equal and opposite voltages, one positive and one negative, referred to a central value (common to earth), in a configuration conventionally defined as ?dual? or a single voltage referenced to earth potential (as is usual).

A preamplifier circuit must be able to guarantee a signal level such as to be able, at least virtually, to bring the entire power stage to the saturation threshold within the limit allowed by the swing of the supply voltage applied to it.

The input (44) for the signal to be amplified is located on the subfront wall (18), belongs to the standard TRS JACK 6.3mm (unbalanced or balanced) or XLR (balanced). The carcass (sleeve) of this ? connected to the ground of the apparatus and the conduction tip (tip) conducts the signal line from the first processing circuit envisaged by the design (figure 8).

Among the signal processing circuits that can be positioned inside the apparatus? possible to mention: filtering circuits in low or high frequency to allow a better reproduction of the signal to the apparatus, avoiding frequencies lower than the resonance frequency of the system or higher than the reproducible spectrum as they would lead to an excessively intermodulated and distorted sound reproduction, reducing the sound efficiency obtainable from the apparatus, up to damaging in a short time the electrodynamic transducers (11) and the power amplifier (32); impedance matching circuit for direct instrument connection, with unity gain or negative feedback; signal equalization circuits, graphic, parametric or fixed cut (changeover); mixing circuits useful for combining the signal of the instrument to be amplified with other auxiliary signals (e.g. input for backing tracks); optional buffer circuits to take the pre-amplified and processed signal before entering the final stage (e.g. headphone output).

A fundamental circuit, which can? be made with some simple diode, ? the soft clipping limiter. This circuit? connected between the last processing circuit and the input of the power amp (32) and provides to transmit a signal which, thanks to the diodes, cannot? never exceed a certain potential, avoiding that excessive harmonic distortion can cause damage to the final stage (32) and to the transducers (11).

All the typical adjustment controls of the preamplification and processing circuits can be positioned on the front (13), subfrontal (18) or upper (15) wall of the apparatus, for convenient accessibility. To reduce the overall dimensions and the aesthetic impact, they can be built-in by means of counterbore on the panel, equipped with knobs that can be pulled out with buttons or traction (37).

In the same way? is it possible to provide processing circuits pi? sophisticated among which we remember those of signal compression and sound effects (such as the classic reverbs, echo, delay, chorus, flanger, tremolo, vibrato and DSP digital processors). Such effects are often impractical when provided directly on the amp, since professional musicians prefer to opt for a smaller choice. free and wide, mostly obtainable? through external devices. Here the instrument signal, before being supplied to the amplifier (32), is processed in a device called ?effect pedal? (62) illustrated in figure 6, with which ? It is possible to adjust the type of effect you prefer in a parametric way.

These pedals (62) are produced in a variety of vast by large and small producers in the world, but they all have in common the need for a negative power supply: the -9V standard? the most widespread, although occasionally finding pedals working at -12V.

The apparatus? capable of supplying, in parallel with the internal devices, an adequate power supply useful for powering various effect pedals (62).

Through a voltage stabilizer regulator ? possible to derive two branches of negative voltages directly from the battery, supplying them on two separate connectors positioned near the power connector (35): the first for the voltage of -9V (351), while the second can? be connected (inversely) directly on the energy group (14) without stabilizer, so that? can supply a voltage of -12V (352).

It is obvious that the greater number of effect pedals (61) will be? connected in parallel to these external connectors (351) and (352) and minor sar? the charge duration of the energy group. For this reason ? appropriate to provide a manual switch (not shown) or an automated system by means of rel? or microcontroller, which deactivates the -9V output regulator if not used: in fact, even if the output of the connector (351) equipped with the regulator were disconnected from any peripheral, the regulator would in any case absorb approximately 1Ampere.

A 5V output disposed on a female USB-A type connector (63) provided on one of the walls of the case, such as the subfrontal one (18) and in turn connected internally with the accumulators (14) or the internal electronic devices ( 32) provides a useful source of recharging for smartphones and other peripherals that can be powered at this voltage, again by means of a suitable voltage regulator.

An additional input for power signals coming from any externally provided power amplifiers can? be installed in the form of a Speakon type connector (161) on a side wall (16) as in figure 7.

A switch (71) positioned on the same wall (16) will provide? then to switch the terminals of the active speaker on this input or on the amplifier gi? operating inside the apparatus, so that it is possible to use the apparatus with an external power amplifier (not shown), eventually turning off the internal amplifier (32), while all the other devices connected to the energy group (14 ) will continue to function normally.

A detailed block diagram of the entire electronic system ? summarized in figure 8.

The sealed case (10) so? prepared in figure 7 pu? be completely covered with shockproof material, such as linoleum, carpet or rubber, possibly completed with shockproof corners (72) in iron, ABS or rubber, taking care to leave the resonator diaphragms, the counterbore of the built-in controls and the power supply.

On the side walls (16) and (17) and on the upper one (15) there can be comfortable handles (not shown) covered in leather or rubber, for an easy grip. Alternatively, the handles can be made in the form of metal plates (73) with rounded edges, which can be lifted upwards like a wing and provided with a sturdy return spring for rapid repositioning.

This convenient configuration allows them to be exploited as quick coupling mechanisms with other devices (90) of the same shape and dimensions, not discussed in this patent. Said devices (90) can be mixing consoles, recorders or other musical instruments. On the sides of these devices are cos? the quick coupling pockets (731) illustrated in detail in figure 9, and each device can? what? mount up to two portable sound reinforcement units, one on each side in a stereo configuration. As visible in the figure, the metal plate (73) is inserted into the quick coupling pocket (731) and the parts are clamped by means of two bolts (732).

The quick coupling pocket (731), equipped with through holes for the convenient fixing on the surface by means of further bolts or through screws (733), can provide a rotating counterplate (74) visible in figure 10, so that the transportable apparatuses for sound reinforcement, once merged with the useful device, can be rotated and oriented towards other directions.

A useful accessory for the support of the apparatus ? provided in the form of a support bar (751), as in figure 10.

At the ends of the bar there are two brackets (75) suitably spaced and shaped for quick coupling with the metal plates (73), while below the bar there is a conventional cylindrical socket (76) sized for housing on rod supports of the standard type and equipped with a throttle pin (not shown) for tightening on them. In this way, the rotating counterplate (74) allows the plates (73) to allow the apparatus a comfortable orientation towards the desired diffusion direction.

The rear wall of the apparatus, as shown in figure 11, however remains free from connections and controls, in order to be covered with a soft sponge cushion (1101) or other silicone materials. This wall can be glued onto the previously discussed battery compartment cover (not shown).

A pair of soft, detachable backpack shoulder straps (1102), secured with hooks or buckles, allow for portability. of the apparatus on the shoulder with the minimum encumbrance, and occasionally the use of the apparatus in mobility?.

The electrodynamic transducer and the passive radiator can be protected by means of special gratings (1103) or fabric masks (the latter being particularly useful for improving the directivity of the high frequency emission), as long as are in a prominent position (1104) and allow the two diaphragms to move freely throughout their range.

Finally, it is necessary to ensure that the apparatus, despite its size and weight, remains firmly anchored to the floor and does not move due to the strong dynamic excursions at very low frequencies, and this? ? possible through a mode? of picketing.

The provision of rubber feet (1105), which act not only as a support surface but also as vibration dampers, may not be sufficient and its usefulness? limited to certain surface types only. For affixing to sand, soil, stone and textiles, ? suitable to opt for ferrules (1106), even if for carpets and rugs the best solution could be velcro tape (1107): this is also useful on smooth surfaces, applying complementary adhesive velcro on them. Anyhow ? it is necessary that the apparatus is always sufficiently raised from the ground to allow the maximum air flow on the underlying wall, where the passive radiator is located.

Particular feet (1108) have therefore been formulated with a rotating orbital surface (1109), on which both the sets of rubber feet (1105), both the sets of ferrules (1106) and the sets of velcro feet ( 1107). Is it otherwise? possible to completely unscrew the bases of the feet (1108) and replace them with feet more? simple or otherwise (not illustrated). On the corners of the lower wall are the four rotating feet (1108), carefully levelled. By rotating these inclined platforms until the mechanical click, ? Is it possible to set one of the three modes? desired stakes and place the apparatus in the correct position for use, based on the support conditions.

A more embodiment evolution of the invention of the present invention, not illustrated, replaces all the parametric controls (until now exhibited recessed on the front wall of the case) with a digital data connector, mounted on a panel on a wall of the apparatus - eg. frontal (13) or subfrontal (18), which can? be, for example, of the USB, micro-USB type or even replaced by a Bluetooth transceiver, connected internally to an advanced control system of the same parameters through the use of so-called ?digipots?, ie digital regulators. This advanced numerical control system can be put in communication (through the connection via serial USB cable or the wireless Bluetooth protocol) with a computer, a tablet, a smartphone or other peripherals intended for remote control of the device; therefore a dedicated software, available for the various operating systems equipped on the basis of the chosen peripheral, allows to adjust the single parameters, instantly transmit the information to the internal control system of the apparatus and modify the settings without the need to to use the physical knobs. In turn, these peripherals can possibly be recharged from the 5V USB output provided on the wall of the case.

A further embodiment of this transportable apparatus for acoustic reinforcement would have connectors (1201) of the socket type (plug-in) on the front wall, illustrated in figure 12. Said connectors have connection points for the power coming from the batteries and connection points input and output of the audio signal coming from the musical instrument. By inserting external ?plug-in? (not shown), bare or cartridge stock ? It is possible to enable further stages of pre-amplification, processing and effect on the previously routed audio signal.

The circuits include a microcontroller architected to control parameters and knobs needed to adjust the circuit; said microcontroller communicates serially with the main control unit inside the device gi? in communication with a previously discussed control peripheral. On the device are cos? the parameters of the external ?plug-in? circuits can be viewed and controlled.

Furthermore, other autonomous forms of control can be provided on the external circuits, such as proximity sensors, interfaced to control the volume or equalization of the incoming audio signal. Through the proximity sensor? ? Is it possible to attenuate the volume or change the frequency response of the lower bands? sensitive to the human ear (between 1500 and 4000Hz) according to the distance of the user from the apparatus.

When not in use, the sockets (1201) can be protected from contamination with dust and sand by caps (1202) in rubber material, shaped in a tight shape for a tight fit.

One more simple embodiment provides a panel which, hooked to the subfrontal wall (18) provides for the direct insertion of the pin into the inlet (44); the panel is powered by the -12V side connection (352) and has all the typical controls of an amplifier panel: gain, equalizers, effects and anything else necessary to prepare the signal for driving in the amplification stage (32) .

Musicians, disc jockeys, music enthusiasts, street artists will be able to face their performances by carrying the apparatus on the shoulder, finally free from the need to having to connect to an electrical outlet, in any place or situation, being able to have a high volume of sound reproduction, extended frequency response and exceptional acoustic performance.

Claims (10)

1. A transportable apparatus for the high efficiency acoustic reinforcement of audio-frequency signals characterized by: an acoustic box (10) of the completely sealed single-cavity type, made of wood or polymeric material, made in the form of a parallelepiped, wedge or spheroid; the presence of at least one electrodynamic diffuser (11), with one or more? coils, integrally exposed to the outside of one of the walls of the sealed case; the presence of at least one diffuser called passive radiator (12) integrally exposed to one of the walls of the case, which makes the dimensioning of the case negligible in virtue of of the possibility? tune the apparatus to the desired resonant frequency; one or more of energy accumulators called buffer batteries (141) of the AGM, Lead-GEL or Lithium-Iron-Phosphate type, incorporated in the apparatus and connected in series or in parallel to each other to form an energy group (14) rechargeable by means of devices dedicated (61); said energy group operating at a continuous voltage between 5V and 18V (possibly negative) up to a maximum of 36V (positive) so as to have autonomy for the operation of the entire apparatus and other external or internal devices, in the absence external electricity network for a considerable number of hours in the space of a day; said accumulators (141) being positioned in a permanent or removable way in a cavity? separate inside the case (10) if equipped with a lid cos? not to obstruct in any way the air flow shared between the two diffusers; special pre-amplification and power amplification circuits (32) internal or external to the apparatus, capable of delivering a total power exceeding 60W even if divided over a plurality of of different outputs that can be coupled together in Power Bridge configuration so that even an electrodynamic speaker with more? coils can be powered by the separate Power Bridge output pairs, said power amplifier being capable of reproducing an audio-frequency signal supplied through external instruments with non-programmable dynamic range (i.e. not subject to amplitude limitations imposed, for example, by means of signal recording) cos? to produce a sound volume higher than 90 dB SPL even for frequencies below 50Hz such as to be intelligible in public and medium crowded places and in the presence of other interfering sound sources such as, for example, another apparatus for acoustic reinforcement or a musical instrument producing an equivalent volume of sound while satisfactorily maintaining fidelity? qualitative for the entire bandwidth of a given signal (portion of the spectrum useful for expressing its sound content); being able to dissipate the heat produced by the internal components towards the outside of the case without compromising the tightness that characterizes the apparatus; the realization in its final form with dimensions, weight and means such as to be easily lifted and transported by hand or on the shoulder by a single person and by anchoring means (1108) to the ground surface which prevent involuntary movements due to excessive vibrations of the apparatus during operation. 2. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising at least one directional tweeter (transducer for high frequency) or an orientable one of the orbital type integrally exposed towards the outside of one of the walls of the sealed case, being connected internally to the amplification stage (32) by means of connection cables, said tweeter being coupled to a filtering stage for high frequencies of the active or passive type (capacitor) and a switch or power rheostat ( also in combination of both) to mitigate or exclude the functionality? of the tweeter during operation of the apparatus. 3. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising, displayed on one of the walls of the case, a connector (44) for connecting a microphone or line coming from outside directly from an audio frequency source or from the output of the signal processing devices (62), even if provided externally in the form of additional modules; said connector being internally connected, by means of conduction cables, to a chain of signal processing devices if provided inside the case, the output of the chain being directly connected to the power amplification stage (32), if provided internally at the checkout; otherwise, in the absence of said chain of internal devices, said connector (44) being connected internally, by means of conduction cables, directly to the power amplification stage (32), if provided internally; said apparatus comprising a power connector of the Speakon type (161) located on a wall of the apparatus as a power input, connected to the active transducer (11) by means of a commutation switch (71) of the signal between the input Speakon (161) and the output of the amplification stage (32) inside the apparatus for the operation of the apparatus with external power amplifications, with the simultaneous deactivation of the internal amplification stage (32). 4. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 characterized by the presence of a plurality of of electronic devices, arranged inside or outside the case in the form of additional modules, suitable for energy transformation, processing and amplification of a sound signal provided from the outside, said circuits being capable, in combination with the power amplification stage (32), to amplify the sound signal supplied from the outside until producing, through the electrodynamic system, a consistent acoustic performance (above 90dB SPL especially at frequencies below 50Hz) and faithful in quality? to the portion of the frequency spectrum useful for the signal that you want to amplify also extended to the most frequent frequencies? low; said electronic devices being powered by the energy group (14) located inside the case and provided with controls (37), buttons and knobs, accessory input connectors (44) and output for microphone, line or power signals (161) possibly exposed recessed on the walls of the case (10), necessary for the regulation of the amplification and processing parameters. 5. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising, displayed on one of the walls of the case (10), an on switch (31) connected between the energy group (14) and any user electronic circuits, processing circuits and power amplification stage (32) and an electrical connector to pi? poles (35) for recharging the power unit (14) from the mains, said connector (35) being internally connected, by means of conduction cables, directly to the power unit (14) or via an intelligent recharging circuit (61) located inside or outside the case, which can? have a parallel switching-type power supply line, for the operation of the device exclusively through the mains, allowing the battery to be recharged simultaneously. 6. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising, displayed on one of the walls of the case (10), a device (33) placed inside or inside outside of the case provided? visible from the outside by means of a sturdy crystal, said device (33) being connectable to the power unit (14) by means of electrical connectors provided inside the case (10), dedicated to raising the voltage supplied by the power unit ( 14) to higher voltages (from 12 to 36V) and monitoring the state of charge of the energy group (14), equipped with a LED diode-type indicator exposed on the outside of the case (10) which, at a certain minimum threshold charge, lights up indicating the need? to recharge the energy unit (14) built into the appliance. 7. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising devices for regulating the voltage supplied by the power unit (14) or by the voltage boosting device (33), connected to electrical connectors (351) and (352) exposed on the outside of the case (10), suitable for powering other electronic devices (62) arranged externally by the user with a direct voltage between 5V and 18V, possibly reversible (negative) up to 36V (positive), and a USB-type connector (63) with a 5V output for recharging smartphones and other peripherals that can be powered at this voltage. 8. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising means for lifting and carrying by hand, in the form of handles which can be made in simple form or with quick coupling (73) for immediate assembly on other devices and equipment equipped with a complementary coupling system (731) and able to rotate on its axis by means of a counterplate (74); said apparatus comprising accessories for carrying on the shoulder (shoulder straps) (1102) and removable lifting means (1108) to lift the apparatus from the support surface, suitable for providing adequate space for the movement of the air in the event which the passive radiator is provided on the underlying wall as well as? to contain the excess of vibrations by preventing the involuntary movement of the apparatus; said means characterized by a rotating platform on which various anchoring means suitable for various types of surfaces are mounted (e.g. rubber feet for smooth surfaces (1105), spikes for soil or sand (1106), velcro tape for carpets and fabrics (1107)); said apparatus comprising waterproof means for covering and protecting against water, dust and bad weather, suitable for rapidly covering the entire apparatus. 9. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising a connector for digital data or a bluetooth device, internally connected to an advanced automated control system of the adjustment parameters of the devices electronics inside the case, (10) said connector or bluetooth device being connectable to external computerized peripherals such as computers, tablets, smartphones or other devices dedicated to this purpose, said peripherals equipped with software dedicated to remote control of the parameters of the apparatus. 10. A transportable apparatus for the high-efficiency acoustic reinforcement of audio-frequency signals such as the one described in claim n.1 comprising at least one socket-type connector (1201), protected by a suitable cap made of polymeric material (1202) when not in use, called socket-type connector (1201) exposed on the front wall to which external ?plugin? circuit boards can be connected, provided bare or in the form of a cartridge, said connector provided with connections inside the case (10) for powering said circuits and deviation of the path of the signal from the input (44) to the power stage (32), so that (see block diagram of fig.8) the diverted signal can be processed by said external circuit boards, provided with physical knobs or digipot , microcontrollers in serial connection with the automated control system for interfacing the parameters of said circuit boards from the peripheral comp used, as well as sensors for detecting obstacles in the vicinity, useful for attenuating the volume or varying the frequency response of the reproduced sound.