KR20070016167A - Closed loop embedded audio transmission line technology - Google Patents

Abstract

An acoustically matched enclosure is provided, which has a drive loaded into the chamber to buffer the throat / entrance of the closed loop transmission line. The transmission line consists of end members, outer and inner enclosure walls, high density linings and throat / entrance sites. The transmission line eliminates internal random standing waves while providing a variable frequency standing wave that compensates for the loss of volume acceleration through superposition of the waves at the final end of the drive output while damping the resonance of the drive. An alternative application of an acoustically impedanced enclosure is to use an acoustic low pass filter to compress load the drive directly into the closed loop transmission line and relay the output to low frequency only through the port. Applying acoustically matched impedance to both sides ensures that the diaphragm of the drive eliminates disruptive internal standing waves, loads properly at all frequencies, and is not affected by room echoes.

Description

Closed loop embedded audio transmission line technology

The present invention relates to an acoustic reproduction loudspeaker.

Loudspeakers are part of everyday life and are used for consumer, commercial, military and research purposes. A typical loudspeaker is an electronic dynamic transducer and has a diaphragm of any depth, diameter or shape. What electronic dynamic describes is a transducer that moves in both negative and positive directions in response to an alternating voltage source to stimulate nearby air particles. At this point, this type of loudspeaker is considered a daily necessity, inexpensive and sufficient in supply. They are always mounted to baffles as part of existing products or structures; Some forms of housing or, in some cases, special enclosures are used for practical acceptance to improve bass performance.

One of the biggest problems is the unique nature of the drive, which favors acoustic impedance over a narrow range of frequencies relative to the size of the drive. Small drives generally have poor acoustical impedance for low frequencies and conversely for high frequencies. The enclosure prefers a narrow range of frequencies and reacts badly to others, producing an excessively incoherent internal standing wave, which modulates the diaphragm with an asymmetrical vibration pattern. This random internal modulation disturbs the driver's natural dispersion pattern and causes electrical feedback (inductive resistance) to the amplification source. Brute force power and heavy gauge wiring are currently being attempted to minimize the effects on sound quality and problems with amplifiers. Another problem is the general acoustic impedance deviation with drive diaphragms present on both sides. The diaphragm must operate simultaneously in two different acoustic environments, because the enclosure creates standing waves that always modify the acoustic impedance of the drive over most frequency ranges. Waves reflected from the room cause further modification of the acoustic impedance of the drive since the frequency is lowered according to the dimensions of the room. Small enclosures are very bad because of the much higher frequencies, which are internally reflected and lack the low frequency capability. The two identical drives will sound different due to only their operating enclosure. It has been recognized in the industry that there are more related problems with midrange speakers, producing a unit with a solid basket behind the diaphragm. This prevents random standing waves from other drives, but creates extreme backpressure over the range of frequencies generated by the midrange drive. This causes the drive to exhibit pronounced acoustic impedance deviations for all operating ranges of the drive and not to produce natural sound.

Loudspeaker drive dimensions favor a particular range of frequencies and therefore it is impossible to make a single magnitude for all frequencies if wide axis listening is desired. The purpose of the design is to produce the loudest loudspeaker of the smallest dimension necessary and to maintain an appropriate level of loudness while maintaining sound representation of the entire frequency range, small distortion, wide and constant dispersion and low cost. Checking this situation appears to be paradoxical, requiring the use and compromise of multiple drives that operate for common acoustical purposes. This is reflected in the current loudspeaker design, which has a technically compromised theory for the purpose of producing a subjectively accepted loudspeaker when the goal should be objective.

A requirement for using a single drive is to come up with a compromise solution that favors low or high extreme frequencies, while attempting to maintain quality in the middle frequency range. The human ear is more sensitive to high frequencies, but the combination of the human ear and brain prefers to listen to all frequencies in the frequency range without phase or frequency aberration blocking the energy flow of the event, otherwise This will be artificial. Sound reproduction is typically for two purposes, for communication and for pleasure. For communication and enjoyment requires unbalanced sound balance and dispersion to balance energy in the listening environment.

The continuous effort for full sound reproduction with predictable field results is highly dependent on the solution to solve the enclosure dilemma. While engineers perceive the enclosure of the drive as a necessary evil or an opportunity to benefit from the created furniture, the enclosure as described herein provides an active operating environment that exposes the true quality of the drive. The result is the elimination of unusual behavior, objective acceptance of sound, simplified loudspeaker design, and predictable results for changing acoustical situations.

The loudspeaker driver works best if all of the electrical energy at the input terminal is converted to motion without mechanical delay or acoustic phase aberration. This simultaneous movement of the entire radiating surface area is a requirement for the proper dispersal of the acoustic energy of the loudspeaker drive if all or part of the voice frequency range is covered. There are loudspeaker designs that have been tried using this exotic and impractical method, with only partial success. Easily available dynamic cone drives have always been selected because of their low cost and the ease with which they can be manufactured relatively easily in variable sizes and shapes. Although this is acceptable and satisfactory for the whole application, dynamic loudspeaker transducers are greatly limited in their ability to accurately reproduce a wide range of frequencies without unusual behavior. It is this behavior that makes every effort to accelerate the performance of a dynamic loudspeaker a costly effort and reduces the return reward. What is presented here allows very small drives to function in applications that were never thought to be possible as a practical way to improve the performance of a basic dynamic drive. Although the performance of the dynamic drive in the product market is the focus of the present invention, it is mentioned in the embodiments in the detailed description that the present invention also benefits foreign-type loudspeaker designs.

The existing loudspeaker market does not focus on the purpose of research and product development efforts in various industries where loudspeakers are used for any purpose. Without such focus, the unique features associated with existing bass loudspeaker technology allow many of the technically unsupported products to remain unresolved. At present, high-end consumers in the industry are taking advantage of the technical weaknesses of the local technical state through costly and unobjective processes or accessories for unfounded demands for improving audio quality. If these practical and ineffective approaches were technically successful, they would be rarely used for the myriad applications of loudspeakers. The proposed invention is applied to the improvement of the basic loudspeaker driver performance and thus to the unchecked field for the technical requirements of the loudspeaker, thus eliminating many unproductive approaches to technical acoustical problems by accelerating their performance. have. Using the proposed technology, a single miniature loudspeaker product using a 3 "drive has been developed and marketed, which is a loudspeaker requirement in many markets when used in single or multiple units while maintaining very low system manufacturing costs. The new market typically includes a specific high resolution two channel stereo, which is intended to listen to the application of commercial sound distribution in a number of units accommodated. It is to enable the foundation of loudspeaker engineering in the art to enable loud and repeatable objective performance and overall improvement.

The proposed invention relates to loudspeakers and in particular to a method for improving the reproduction quality of very low, low, medium and high frequencies, which reduces relative enclosure dimensions, reduces system costs, and improves the performance of the room. It is to reduce the acoustic dependence on. Such an improvement reflects the way of enclosing the drive, which is free from deformation by the overall ambient acoustical environment with respect to the acoustic impedance, and drives of substantially the same diameter, Alternatively, it can function as a subwoofer unit that operates primarily over the full range, extending the response to the lowest region of the frequency range. Although the focus of the present application is on small speaker units, this technique can be used for large bass sound reproduction, full range sound reproduction, or sub-bass sound reproduction applications. This improves the performance of large drives as well as midrange and tweeter drives. Focusing on the operation of the sub bass range generally involves the use of a port or horn to reduce the movement of the diaphragm in proximity to the maximum low frequency output range. Large drives produce lower bass with small diaphragm movements, but would be less advantageous for directly radiating a full range of operations due to limited high frequency performance. The low frequency may radiate directly in one embodiment or may radiate through a port or horn in another embodiment. EATL has regular standing waves and maintains a constant internal enclosure pressure over the desired frequency range, causing linear air volume displacements internally, resulting in more accurate movement of the drive diaphragm. This results in a favorable standing wave when relatively long wavelength signals stimulate the EATL, resulting in loading the drive diaphragm by modulating the air volume of the main enclosure in real time. All wavelengths exist in some finite length within a partial or complete line governed by varying dynamic air densities. Any pressure stimulus from the drive causes dynamic molecular disturbances in the EATL, creating a desired standing wave that displaces the diaphragm with greater ease and accuracy than the original electrical stimulus. This improved physical displacement is the result of the drive voice coil being stimulated by an electrical source modulated by the dynamic standing wave established within the EATL. This predictable internal loading pattern precedes all other external drive diaphragm stimuli to provide critical damping, optimal acoustic impedance with frequency and resistance to room reflections.

In addition, the technique herein utilizes a compact drive that is normally effective only in the high frequency range, allowing the compact single drive shape and dimensions to be optimized for full range and sub bass operation. The enclosure developed using the present application determines the acoustic impedance preferred by the same drive.

1A and 1B are side and front cross-sectional views of a preferred embodiment of an embedded acoustic transmission line (EATL) of indirect direct coupled (IDC) according to the present invention.

FIG. 2 is a cross-sectional view of an enclosure made of material and external dimensions such as the enclosure of FIG. 1 without including the EATL feature.

3 is a cross-sectional view of the IDC EATL side of FIG. 1 in accordance with the present invention, with the side marked to show the extension portion;

4A and 4B are front and side cross-sectional views of the IDC EATL of FIG. 3 in accordance with the present invention with a reflex port added to the enclosure.

5 is a cross-sectional view of a preferred embodiment of a direct coupled (DC) EATL in accordance with the present invention.

6 is a cross-sectional view of a preferred embodiment of DC EATL physically combined with a standard non-damped bass reflex enclosure.

7 is a simplified diagram highlighting the features needed to represent the use of EATL technology as a flat speaker.

8A is a simplified diagram highlighting the features needed to represent an IDC EATL system with frequency division in a multi-way.

FIG. 9 is a simplified diagram highlighting the features needed to illustrate the use of EATL with a horn coupling device.

FIG. 10 is a side cross-sectional view of the preferred embodiment of the loudspeaker system shown in FIG. 1, wherein the port has been replaced with a passive radiator mounted on a baffle board with a drive. This figure shows the association with the parts suitable for this mode of operation.

FIG. 11 is a simplified illustration of a band-pass mode of operation of the system of FIG. 1, with an acoustic low pass filter coupled to the front of the drive using a port to radiate sound. FIG. ). The important parts of this mode of operation are shown.

12A, 12B, 12C, and 12D are graphs of the performance described in the specification and are indicated by the reference numerals described in the specification.

13A, 13B, 13C, and 13D are graphs of the performance described in the specification and are indicated by reference numerals described in the specification.

14A, 14B, 14C, 14D, and 14E are graphs of the performance described in the specification and are indicated by the reference numerals described in the specification.

Throughout this specification, reference will be made to certain items, figures, names, idioms, and notable words. The items will appear first in bold capital letters, and in the following sentence they will be abbreviated as bold letters. The first letter in bold and the abbreviation in capital letters will appear later to recall the memory. Some important statements may be underlined for recognition purposes. Certain names may have significance herein but may not be directly related to the features herein and will not be emphasized or underlined in this manner. 1 shows a preferred embodiment of the present invention. 1A and 1B show side and front views of a completed Direct Radiator Enclosure (DRE) speaker assembly, constructed in accordance with the present invention. Bernoulli's theory of fluid flow states that a pressure deviation must exist for the fluid to flow from the container through the outlet opening to the same pressure region as the container. This simply means that in order for an acoustic (fluid) wave to be generated by the loudspeaker, a pressure deviation must exist between the loudspeaker's diaphragm and atmospheric pressure and the pressure deviation must be consistent for all frequency and acoustic conditions. All drives involved in the present invention are bi-directional, which means emitting sound from both sides of the diaphragm. One side of the driver diaphragm DD (3) must be mechanically isolated from atmospheric pressure at all frequencies within its range, regardless of atmospheric pressure (AP) change. Mechanical isolation means isolation from atmospheric pressure when moving, not static isolation.

FIG. 1A is a side cross-sectional view of the DRE 29 enclosure, configured to receive air pressure through the throat / inlet 6 behind the drive 41 mounted to the separator 7, but with the air chamber (FIG. 10) with an embedded acoustic transmission line (EATL 5) of indirect coupled (IDC) buffered by 10). EATL 5, which is not the same as conventional transmission lines, has a throat and an entrance at the same point through the overlap. What IDC means is that the wave entering the EATL 5 passes through the air chamber 10 of some relevant volume, thereby indirectly correcting its volume in real time, although the effect on the DD 3 is indirect. The EATL 5 consists of a waveguide 20 of the outer cabinet 1 and a waveguide 21 of the inner enclosure 2 separated by a spacer 9. The EATL 5 may extend using the side cabinet wall waveguide 21, which is unique in the construction of the inner box with respect to the extensions of the waveguide 20. These extensions of the EATL 5 are 20A and 21A, allowing the EATL 5 to operate at a lower frequency than having only the waveguides 20 and 21 but are overall relative to the size of the drive 41. The EATL 5 is sealed by the termination member 13, which includes a wave at one end of the EATL 5 to reverse it and is located at the center (from each corner) as shown in FIG. 1B. Dynamic Standing Waves (DSW) are generated at the throat / entrance 6. Definitions of terms such as throat / inlet 6 result from reflected waves having a point of exit at the same point as the point of inlet of the wave. The fact that in / out waves can overlap one another is in accordance with the unique pressure feedback principle above. The air volume in the EATL 5 is always small compared to the working volume of the chamber 10 of FIG. 1 or the chamber 19 of FIG. 6 and is not to be confused with any type of closed closed band box. Overall dimensions can be further reduced using reduced model construction techniques to improve the output of small drives in small spaces as well as OEM tweeter configurations in which rear waves are collected and returned as advantageous standing waves. Spacing dimensions can be reduced or increased as needed and the EATL 5 can be repeatedly folded to increase the length as needed if the lengths of 20A and 21A are not appropriate.

The EATL 5 is lining with an alternative Density Transmission Medium (ADTM, 4), which in a preferred embodiment is an open cell urethane foam, which has a normal air density and high It is inert at frequency and accepts new air particles randomly, but at low frequencies when compressed, additional air molecules can find and expand in volume within the cell structure, but instead lose heat dissipation. This is a lossy process of damping of the driver Resonance Peak (DRP) and DSW shown as A of FIG. 12B and C of FIG. 12D, while FIG. 12B is an impedance curve for the preferred embodiment. Damping is a term that refers to the vibrating body's ability to stop motion immediately when the stimulus is removed.

The relatively high frequency wave entering the throat / inlet 6 of the EATK 5 only needs to be within a few inches of the drive diaphragm 3 reaching its wavelength at normal air density. The standard enclosure of FIG. 2 is, for example, only a few inches deep, meaning that any wave below 10 kHz experiences the enclosure echo almost instantly. FIG. 2 shows an enclosure 11 of air volume with the same dimensions as in FIG. 1 but without 2 and 4 of such a structure. Waves traveling the stream line 15 enter the inlet 6 of the EATL 5 and travel through the EATL 5 with little interaction with the surface cells of the ADTM 4 so that it is terminated ( It expands almost immediately until it reaches 13) and then reflects the wave back towards the drive diaphragm 3. The throat / inlet 6 at the inlet of the EATL 5 will experience a node and an anti-node (DSW), which overlaps and causes pressure in the chamber 10 behind the drive 14. Affects and is considered positive pressure on the AP. As the frequencies are lowered from what was initially affected, the EATL 5 is due to the DSW condition caused by the depth migration indicated by the streamline 14 and the DSW condition of the air space 8. A constant amount of pressure will be maintained on the drive diaphragm 3. Since the varying wavelengths / intensities occupy the deeper depth of the ADTM 4 cell structure, they generate individual DSWs and thus dynamically improve the motion of the drive diaphragm 3. The individual DSWs generated will integrate their pressures and will generate multiple DSWs simultaneously (overlapping) in the presence of multiple frequencies. The waveguides 20 and 21 must be maintained at close intervals to contain the wave energy while directing the wave energy to the termination member 13. In a preferred example, 20, 20A, 21, 21A are 12 mm and 9 mm apart respectively and will vary somewhat depending on the diameter of the drive and the purpose of the system. The drive 41 will see the influence of these DSWs as its acoustical impedance, since the variation in pressure influenced by the atmosphere is maintained with frequency. DSW is the result of resistance by the ADTM 4 material to varying frequencies, compliance of the drive and acoustics entering the cell. The resulting interaction of the three excitation variables keeps the pressure in the chamber 10 constant as a change in frequency while the drive speed remains linear. The internal pressure of the chamber 10 is a complex DSW resulting from the signal input of the voice coil 28 and the initial movement of the DD 3, the static pressure of the chamber 10 and the positive pressure generated in the EATL 5. Will be This resulting composite pressure is constant and relative to the intensity and wavelength in the EATL (5) and determines the DD (3) movement.

The length of the EATL 5 is directly related to the limit of influence of the low frequency of the EATL, as clearly indicated by the curves of FIGS. 12B and 12A. In FIG. 12B, an impedance plot of the speaker system of FIG. 1 is shown. There are two peaks associated with this impedance plot. The large peak A is a DRP occurring at 150 Hz and the other peak B occurring at 500 Hz represents the quarter wave impedance of the EATL 5 of FIG. 1. FIG. 13A shows the frequency response when the length of 2 cm is long such that the enclosure of FIG. 1 becomes the enclosure of FIG. A 2 cm increase in enclosure depth 26 in FIG. 3 can be interpreted as a new EATL (5) vertex (E) at 400 Hz in FIG. 13A, so that at the throat / entrance of the EATL (5) to be treated with DSW. Causing a 100 Hz downward movement of the quarter wave frequency. The main drive resonance frequency of FIG. 3 does not change noticeably when the chamber 10 increases as shown by 40 of FIG. 13A. Also shown in the frequency response plot Q of FIG. 14E of FIG. 3 is the lifting of the output starting at 400 Hz instead of 500 Hz of the shallow enclosure shown in FIG. The large vertex C can be seen in FIG. 12D (this is the standard closed type enclosure 29B of FIG. 2 with the same drive), but the vertex of the EATL 5 as in FIG. 1 or 3 ( There is no properly damped (controlled) impedance peak A for B). The volume change of the chamber 10 has little effect on the drive resonance frequency C of the drive 41, which exhibits the effect of ATEL 5 to delay the wave at such a short distance. Damping of the DD 3 improves the acoustic impedance for the bass frequencies, which reduces the cut-off slope for better overall instantaneous performance and deep bass extension. The peak B of the EATL 5 at 500 Hz in FIG. 12B represents the lowest frequency supported by the EATL 5 in FIG. 1 to correct the sinked output of the DD 3 (FIGS. 12A vs. 12C). , The sagging output occurs above the normal drive box resonance frequency (C), and the EATL (5) oscillates at and below such a resonance frequency, close to the resonance frequency of the drive of FIG. 12B. Occurs at the point where the condition begins to attenuate.

The impedance curve of FIG. 12D for FIG. 2 shows the position of the drive resonance frequency C as in FIG. 12B for FIG. 1 and FIG. 13A for FIG. 3. The curve of FIG. 12D clearly shows that this vertex C occurs at 150 Hz, and if closely followed above this point, the vertex B of EATL 5 as in FIGS. 12B, 13A and 13B. Indicates that there is no. If the curve U of FIG. 12A for FIG. 1 is observed, it will indicate an increase in output starting at 500 Hz, or point to the same impedance peak B of EATL 5 of FIG. 12B. All frequencies above this peak will indicate an increase in output, which increases the gain, increasing and maintaining a flat response. The gain in efficiency is averaged to 6 db when averaged at several points above 500 Hz in this particular example. The only way for this to happen is that a constant pressure from inside the enclosure as the frequency increases increases so that the proper DD (3) speed is maintained. This process does not change the parameters of the drive 41 acoustic signal that effects masses and random internal standing waves have in their operation. The frequency peak UU of 500 Hz in FIG. 12A for FIG. 1 is not present in FIG. 12C, the graph for FIG. 2, and does not increase at 10 kHz. At point TT at 500 Hz in Fig. 12C, there is a dip and only a small, non-remarkable peak that degrades the response.

The vibrating body experiences the largest movement at resonance for the same stimulus and small movement above and below that frequency. The output (speed) drops much faster below resonance due to compliance, while at slower rates due to mass above resonance. Loss of output above resonance is directly related to the mass (as needed at higher frequencies, which affects the acceleration of DD (3)), while the DSW in EATL (5) is directly related to frequency and loss Increase the pressure to counteract and keep the pressure constant with increasing frequency. Since each frequency may require a complex wave to maintain maximum signal transfer over atmospheric pressure, the internally generated DSW at the inlet of the EATL (5) will produce an amount of pressure buffered through the air volume of the chamber (10). Provide in real time. Random standing waves present in the enclosure of FIG. 2 create pressures that are not correlated to the various parts of DD (3), disrupting the dispersion pattern to affect its phase characteristics. Loudspeaker driver engineers cannot predict the effect of an enclosure used in the field when determining product parameters. Designs developed to predict the dispersion and vibration characteristics of a given drive diameter would not be useful if the chaotic internal standing wave patterns of the enclosure would allow modifying the radiation pattern of the DD (3). This is one of the main reasons for engineers seeking various types of suspension 27 and DD (3) materials as a solution to resist the breakup of DD (3) caused by unpredictable situations. These breakup patterns are caused by random standing waves, which are dynamic and linked to the enclosure 1, source signal and level. The attenuated energies that cause the random standing waves must be related to each other, but should not be as disturbing as in existing enclosure designs if the characteristics of the drive are maintained or improved. The removal of random internal standing waves and the generation of useful coherent waves allow the drive 41 to operate in an environment that maintains a positive dynamic pressure with a frequency for a static ATM. The result of this acoustically induced internal positive pressure reduces the collapse of the diaphragm when a modified pressure is applied to the entire surface to reduce the effect of the solid transfer breakup mode. This is the collapse mode that occurs when the voice coil 28 is stimulated. The initial stimulus in the voice coil 28 causes the speed of the DD 3, the bending of all materials, and the physical transfer of mechanical energy as a physical wave towards the edge of the DD 3. At the outer edge of the DD 3 there is some form of flexible material 27, which surrounds and is secured to the diaphragm to allow the overall movement of the overall movement assembly when the voice coil 28 stimulates the movement assembly. It is desired to have energy that travels through the mechanical path of the cone and is dissipated from the diaphragm material and dissipated into the surrounding material 27 with kinetic energy and which in most cases does not occur. The diaphragm and surrounding material 27 do not absorb all the waves and some reflect back towards the center or toward the original point. In doing so, coherent and non-coherent waves physically impinge on the DD (3) material, causing regions of positive and negative standing waves to exist on the DD (3) surface to change the dispersion patterns. Patterns of this type can be observed and considered during the engineering design phase, possibly making the drive 41 better. EATL 5 will minimize audibility in this type of breakup mode, but will not eliminate them.

The diagram of FIG. 4 shows the IRE enclosure 29 of FIG. 1 or 3, which includes a port 17 to enhance bass frequencies. The addition of the port 17 does not affect the DSW at the throat / entrance 6, where the DSW maintains a high frequency through the EATL 5, the main purpose of which is to drive the drive 41 in this embodiment. It corresponds to a mass that causes signal loss above the resonant frequency. EATL (5) provides an important damping for DD (3) to improve stability at low frequencies as compared to Figure 12B for Figure 1 and Figure 12D for Figure 2. These impedance plots indicate that although the resonance frequency remains about the same for both enclosures, the peak A in FIG. 12B is DD (since a controlled peak ratio is achieved for smoothly extended bass response and characteristics). While the appropriate damping of 3) is shown, the impedance plot of FIG. 12D shows that the drive 41 has a high and sharp resonance peak C, resulting in a sharp and loose resonance sound. This highly damped condition is maintained with the port 17 included to extend the bass response in FIG. 13B of FIG. 4. The impedance plot of FIG. 13B has three prominent vertices with port vertex F and saddles (G) (box resonance frequency) before drive resonance vertex H, which is well damped drive 41. As generated with, the drive allows high frequencies to start at 400 Hz and lift at the same time. Compared with the drive of FIG. 2 with the impedance curve of FIG. 12d, the drive 41 of FIG. 4 has three vertices of FIG. 13b, which are above and above the drive resonance peak H due to the controlled standing wave. Shows the output increase below. In observing the frequency position of the peak I of FIG. 13B caused by the positive internal pressure of the EATL 5, the graph relates to the enclosure with the port of FIG. 4, 9 mm deep, 400 Hz in the graph. It can be clearly seen that occupying the position has been described previously. The vertex I and the driver vertex H of the EATL 5 of the impedance curve of FIG. 12 remain in the same position, having improved (appropriately damped and extended) low frequency and (maintained speed) high frequency. Represents a well loaded speaker system. Shown in FIG. 10 is a simple diagram using a suitable passive radiator 30 that replaces the port, which operates in conjunction with the drive 41 to extend the bass to a lower frequency. The use of the passive radiator 30 maintains the sealed condition of the acoustic system but all configurations do not benefit from this type of resonance system. Passive radiator 30 requires more mounting sites as a whole and would be appropriate for large systems with more available separator plate 7 sites. The EATL 5 configuration of the passive radiator 30, if properly aligned and has a curve similar to that of FIG. 13B, will retain the same general characteristics as a system with ports. Another arrangement for the DRE 29 is to couple the front of the drive 41 to an acoustically low pass filter as shown in FIG. 11. The port 17 or passive radiator 30 can act as an acoustically low pass filter with respect to the air volume 31. Here EATL 5 provides constant pressure loading, damping, improved high bass output and control, while port 17 sets up a box loaded with air volume 31 which reduces the amplitude of DD 3. Thereby allowing the sealed air chamber 10 and better damping. The above design will have three impedance vertices, one before and after the DRF, like the vertices of the EATL 5 design with different ports. As in the previous example, the passive radiator 30 may be present to resonate the new air volume 31 present in front of the drive 41 when mounted in at least one wall of the additional enclosure 32. . The IDC EATL 5 acts substantially as an ideal impedance matching device for conventional types of drives and loading methods. This creates two ranges of increased pressure to benefit frequencies above and below the resonance of the drive. The frequencies above resonance may be emitted directly over the entire range, or the DD 3 may be loaded into an acoustically low pass filter to focus on the range of bass frequencies.

Any drive will have an optimal operating frequency range where regeneration is most appropriate. Especially at high power levels it will be very difficult if not impossible to perform full operation with one drive 41 over a range of 20 Hz to 20,000 Hz. The optimized enclosure DRE 29 of the individual EATL 5 can concentrate its advantages in a narrow acoustic range to assist the drive in the optimum range.

This is for the purpose of dividing the acoustic ranges to use the optimal drive for each range (Figs. 8B-29H, 29M, 29L, 29VL) using individually optimized EATL (5) enclosures, or at the same frequency range. May be for the purpose of increasing the sound level in a single range (FIGS. 8A-29A, 29B, 29C, 29D) using multiple EATL (5) enclosures operating at It may be. This type of operation is improved due to the positive pressure behind each drive and hence the resistance from interference with each other diaphragm. The usual close spacing of the drives results in many unpredictable effects because the random nature of the individual internal and external standing waves changes the dispersion pattern. The coherent output of the EATL (5) enclosure is combined in multi-way speakers to make crossover from one drive to another more smooth and free of lobes. Will be. The coherent output of the grouped reinforcement drivers, whether clustered or line arrays, will be performed according to the intended theory. Special housings 16 may be used to adjust the DRE 29 unit appropriately for the application.

The EATL 5 can be used in connection with an exotic acoustic transducer, such as an electrostatic and dynamic flat type diaphragm as shown in 29A of FIG. Flat panel loudspeakers typically radiate in two directions that are not limited due to the negative effect of the placement of the enclosure or adjacent wall relative to one side of the sensitive diaphragm. Randomly reflected standing waves are much more damaging because of the large diaphragm surfaces needed to generate this type of meaningful sound level. 7 is a simplified diagram showing important reference parts for the EATL 5 used with such flat panel type loudspeakers. The EATL 5 consists of the basic parts as shown, with only the flat panel as a version of the dynamic drive 41 and the adjustment of certain other parameters included with the EATL 5 structure. Certain types of extraneous drives can be used and only benefit from the IDC of the EATL 5, which is the case for the flat speaker DD 3. Shown in FIG. 9 is the use of a horn extension apparatus 42 mechanically coupled to the IDC EATL 5 enclosure 29 for better transmission advantages. Horns are generally used to increase the level, distance and coverage of certain times at a particular site while shadowing other sites. The close coupling of the horn extensions to the normally included drive 41 of the DD 3 of FIG. 2 generates a strong echo to the DD 3. Typically, these reflected features are acoustically amplified so that the DD 3 undergoes a horn bell type reflection that competes at its surface, so that the drive 41 coupled to the horn is chronically collapsed. suffer a breakup. A phase plug 25 may be needed to maximize pressure transfer depending on the diaphragm type. The same drive 41, which operates with the positive pressure of the DRE enclosure 29 assisted by the EATL 5, is enhanced to not suffer from this reflection effect, resulting in a much clearer output from a well designed horn coupling.

Application examples of low frequency only directly coupled

Conventional loudspeakers require large diaphragm sites and / or high masses to generate low frequencies with low bands and relatively high efficiency in the process. The current process for bass reproduction is inherently efficient because they operate at the resonant frequency or in close proximity to the resonant frequency resulting in boomy like sound quality. Parameters such as resonance are the first harm of the finished acoustic system, although it may be included in the performance of any speaker system. The DC EATL (5) mode of operation will match the acoustic impedance of the very small drive to produce low bass frequencies at normal SPL levels. Matching the acoustic impedance in the desired frequency range is the first consideration in reducing distortion at low frequencies, but acoustic output is also considered when the drive is small. EATL technology allows the primary importance to be met with large drives, as well as very small drives capable of producing a useful degree of personal (small application) low bass frequencies. While large drives have been developed for low frequency reproduction, in today's basic enclosure configurations they are not acoustically matched for very low frequencies and have problems in resonance and room echo. The EATL 5 provides a practically dimensioned, acoustically neutral enclosure platform, which originally had low static resonance, extended low frequency response and removal of room reflections. immunity). The sub-woofers design, based on the EATL (5) enclosure, acoustically harmonizes with any type of speaker requiring low frequency extension and provides natural room reflections due to the unusual irregular alignment described below. Removed.

5 shows an example of the application of the EATL 5 associated with the dynamic drive 41 for the purpose of generating only very low frequencies, which is referred to as a direct coupled (DC) EATL (5). The DC EATL structure is very similar to IDC, with the exception of a large throat / entrance opening 6, such as a drive diameter, and a compression plug 12 located just before the drive 41. The EATL 5 is directly coupled to the drive 41 with a minimum volume of air volume in the chamber 10 between the throat / inlet 6 and the drive of the EATL 5. The drive is mounted with the inlet 6 of the EATL 5 facing forward to make a high compression chamber 10 for driver loading. In this mode, the drive 41 is compression loaded so that the compression plug 12 is used to assist the direct wave movement to the EATL 5, to minimize air turbulence at the throat / inlet 6 of the EATL 5 and to reduce the EATL. Establish the correct throat / entrance 6 to (5). The DC coupling will place the drive 41 completely under the influence of the EATL 5 and will follow the frequency pattern it establishes. ADTM 4 allows for wide DSW bandwidth by establishing wave delays through depth migration. The low frequency above the resonance of the drive 41 is not made easy by the cellular structure and will maintain a constant pressure due to the DSW in the EATL 5 before the depth movement actually begins. This can be seen in Figures 13C and 14D. The frequency response curve of FIG. 13C shows the output of the drive 41 of the EATL 5 and the DC drive, with a frequency response of 12 db / oct drop output from the drive 41 and a smoothed response above the drive resonance of approximately 400 Hz. It can be seen that. This curve represents a dynamic pressure that is much greater than atmospheric pressure for all frequencies in the system's bandwidth and a consistently high amount of pressure on the DD (3) for frequency. At DD 3 this signal, when measured at 100 Hz, is 40 db greater than the signal at the inlet of port 17 when the system is assembled. This output curve represents the actual curve of the drive 41 when measured close to the rear of the DD 3 with the positive pressure applied in front of the DD 3 due to the DSW loading by the EATL 5. A similar pattern will occur in free air, except that the 12 db / oct slope starts at the drive's free air resonance frequency. Curve S is a reference high pressure curve with a predictable drop of 12 db / oct ratio and is easily shaped with an acoustic low pass filter fixed to the other side of the cone. This curve S of FIG. 13C also reflects the predictable falling diaphragm deviation for low frequencies and is not affected by the passive lower pressure loading environment of the acoustic low pass filter. An acoustic low pass filter 18, preferably a reflective reflex enclosure, will further reduce DD (3) motion in the bass power frequency range (30 Hz-60 Hz) and in the ultra low frequency range (<20 Hz). ) Does not require subsonic filters to control distortion. The acoustic low pass filter 18 connected to the drive 41 EATL 5 in FIG. 5 prefers the lowest frequency even though these frequencies drop in the curve S of FIG. 13C. The 12db / oct drop output of FIG. 13C is transformed into the curve R shown in FIG. 13D of FIG. 6, which represents a 6 db / oct rise output from 70 Hz. The curve of FIG. 13C is generated with the drive 41 only in a high pressure environment, which will resonate the box with little effect on the constant high pressure loading of the drive. This controlling positive pressure allows the output behind the drive to resonate the reflective enclosure with acoustic volume 19 at a frequency within a 12 db / oct slope. The efficiency in the range of transformation is moderate compared to the driver mid-band efficiency, but the driver, a small, small mass, generates a fast response diaphragm to produce useful bass at the frequency determined by EATL (5). Make it available. Drives 41 of approximately the same diameter used in IDCs of the same dimensions will generate the curves of FIGS. 13C and 13D if the compliance is not severe. Positive pressure of the quarter wave is applied to the DD 3 to generate improved low pass performance from the drive 41, as indicated by the peak R in FIG. 13D for FIG. 6. An acoustically applied real-time mass component. The mass and other parameters of the drive 41 will affect the distortion, efficiency and, to some extent, affect the extreme frequency cutoff so that the optimum performance from the particular EATL / reflective enclosure 29I of FIG. 6 is achieved. Can be made through the selection of 41. The efficiency of the EATL / reflective system is still related to the actual DD 3, and as it is normal as more air particles move, the efficiency is increased with the large drive 41. Since the mass typically blocks the output at high frequencies, the low frequency output of the large drive 41 is increased compared to the mid band output because of the diaphragm portion. The low frequency system of the DC EATL 5 develops the output from the diaphragm area rather than the geometry. Listening rooms, which are typically acoustical spaces with gains in dimensions, prefer low frequencies if they exist. The curve of FIG. 14C shows the microphone placement in the distance when the sub-bass system of FIG. 6 is measured. The room works similarly to the reflex enclosure, which outputs at low bass frequencies due to a significant increase in gain to 15 Hz octave over close frequencies as shown by curve (C) in FIG. 14C. To support. 14A shows the impedance of FIGS. 5 and 6. The curves are overlayed to show how small the reflex box changes the resonant frequency and its Q when the drive loaded with EATL 5 is connected. What this indicates is that the positive pressure in the EATL 5 dominates the impedance of the drive without affecting the operating parameters of the drive 41 / EATL 5 from the addition of an acoustic low pass filter. The large peak K in FIG. 14A represents the impedance of the driving unit of FIG. 5. In FIG. 14A, the small peak J leading to the drive vertex L will be considered as a port peak with a conventional reflex enclosure and the output is rapid as the frequency approaches these peaks. Will descend. These vertices represent the same EATL 5 vertices observed at the impedance vertices of FIGS. 12B, 13A, and 13B, except that the vertices are pushed down the drive resonance due to the close coupling of the EATL 5. Increasing the length of the EATL 5 has been shown to lower the peak of the EATL 5 as the close coupling causes. The depth shift of the ADTM 4 is large under high pressure causing a quarter wave signal to appear in the drive diaphragm under box tuning. As observed in FIG. 13D, the output will drop after the main EATL 5 peak, but close coupling will load the drive at the cutoff frequency of the EATL 5 near 15 Hz. If carefully observed, the output curve R of FIG. 13d of the sub-bass enclosure of FIG. 6 has the highest output at EATL 5 at 35 Hz, which is an unusual feature. Observing the curves in FIG. 14D can understand why. 14D shows the phase curve of the subwoofer in FIG. The curves are overlaid to show their relationship. Curve M represents the microphone placement very close to the drive diaphragm at the surface boundary of the drive diaphragm, which will represent the curve of EATL 5. Curve N represents the output at port 17 of the same sub woofer as shown in FIG. 6, and it is clearly visible a large change in phase starting at 55 Hz close to the box tuning frequency. The outputs of DD 3 and port 17 are remarkably similar until the phase shift starts at the box frequency G of FIG. 14A, so that the initial rise at the output as shown at G in curve R of FIG. Generates. The phase curve M of the driver shown in FIG. 14D represents a change in inverse starting near the same point, 55 Hz, where a small depression is indicated through the remainder of the phase curve at the driver. This depression indicates that high pressure is applied to the DD 3 to cause a phase change at the port and corresponding increase in output. This pressure is applied when the DD 3 is under box loading for maximum effectiveness. The pressure on the diaphragm remains constant at 55 Hz as observed by the flat phase curve, and does not change even when the EATL (5) vertex loads more of the diaphragm resulting in increased output. The result of feedback and box loading of the EATL 5 establishes an effective acoustic low pass system, which will enable the generation of very low frequencies at any practical drive diameter, as compared to the normal low frequency output of the drive. . This is slightly below the overall midband efficiency and is proportional to the drive size.

If physical space is not a practical consideration, horn loading of the drive for low frequency regeneration may be effective while in DC compression mode of operation. The well-loaded drive 41 is a good candidate for horn coupling to the surroundings, but a large surface expansion area is needed to support oscillation of long waves. In some cases, applications embedded in buildings or large structures will allow portions of the structure to act as horn wave-guides. In some cases, folding the required waveguide will allow a low frequency horn to be performed in an enclosure version.

Of course, multiple units of the DRE 29 enclosure of the IRE 29I together with the EATL 5 can be configured to increase the output as a coherent source as shown in FIG. 8A so that the sound can double the unit. Each time you would theoretically approach 6 db more. This and the elimination of good room echoes will maintain the integrity of the source. The IRE 29I may be combined such that the EATL 5 vertices occur in different ranges as in FIG. 8B to maximize the output in each range. This will allow maximum low frequency output over a wide range.

A preferred example of extreme application of IDC and DC systems used simultaneously in a single acoustic system is shown in the graph of FIG. 14B. The curve of FIG. 14B shows three identical 3 inches operated in a reduced model (<.06cu. Ft.) DRE 29 and IRE 29I enclosures having approximately the same size as shown in FIGS. 1 and 6. The diameter drive is used to represent an audio range of 35 Hz to 20 kHz. These are the subwoofer of FIG. 6 which reproduces low bass from the left speaker of FIG. 1, the right speaker of FIG. 1 and both channels. The 3 inch drive 41 shown in FIG. 1 is the only candidate for this type of system, which has sufficient diaphragm area while the drive maintains the dispersion properties required for the tweeter or high frequency drive. This is because its impedance can be matched by either DC or IDC coupled EATL 5 to cover the entire frequency range. The free-air resonance of the drive is normally 100 Hz too high for subwoofer operation, but the DC EATL / Reflex Enclosure 29I covers a range between 35 Hz and 125 Hz, where 125 Hz to It is matched with IDC EATL enclosure 29 using the same driver type covering a range between 20 kHz. The DC EATL / Echo Low Frequency System 29I electronically adjusts its high frequency range and volume, and is powered by a separate amplifier to properly mix with the IDC EATL Enclosure 29 in any field environment. It may be set to. Such a system achieves vertical and horizontal off-axis responses close to full and does not require additional parts within the enclosure. The system output shown in FIG. 14B can be achieved in excess of 90 db at a listening position in a room of average size over the indicated frequency range. The system, which includes two speakers, a subwoofer, an amplifier, a tripod stand and all the connection accessories, was manufactured in a basic form intensively in a standard briefcase.

Most of this application includes confirmation of the effectiveness of very simple processes. Only a few drawings are needed to represent the above basic technique for improving sound quality so effectively. There will be many ways to use the general principles of the technology because of the general features of the enhancements included herein. For example, while incorporating the basic principles of EATL 5 in some way, new products with different shapes may be developed, or new ways of incorporating EATL 5 to atmospheric pressure may be found. Using the principles described herein is an infringement, although such changes or modifications are not expressly expressed herein. Once a person skilled in the art directly realizes the immediateness of the problem, consults the drawing, and experiences a negative difference, it will be very easy to duplicate and improve the process without a high degree of understanding of the theory. If the same basic elements that couple the drive 41 for the same purpose are physically connected to the enclosure in the same way, any device that derives the basic purpose for the same reason that the EATL 5 derives its purpose. Even if it would be an infringement of the present invention. This means that not all studies of the depth of implementation and features have been investigated, so reassignment of specific features to various locations does not allow the breach to be overcome, which is the inventor's continuing effort.

The present invention can be used to manufacture a loudspeaker.

Claims (10)

An enclosure having six outer walls and six inner walls connected to each other to form a box structure, three of the inner walls being one of three waveguides forming a closed loop embedded acoustic transmission line; The other three walls are also placed in the first enclosure using one of the walls of the first enclosure to complete the structure, forming a second desired waveguide constituting the embedded acoustic transmission line. As a second enclosure; A termination member fixed to an end of said transmission line to form and seal a third required waveguide constituting an embedded acoustic transmission line; At least one aperture located at the back of the second enclosure of at least one inner wall, preferably of a proportional diameter or portion making the throat / entrance open to the embedded acoustic transmission line; An alternative density transmission medium fixed to at least one of the waveguides and covering most of the surface of the waveguide; At least one opening in a wall common to both structures, later referred to as a baffle board, to allow mounting of at least one two-way loudspeaker transducer; An apparatus for improving acoustic impedance for a loudspeaker transducer, comprising at least one two-way radiating loudspeaker mounted to the partition plate. The method of claim 1, The internal enclosure is provided with tuning means for attenuating low frequencies of the speakers, Port means extending through said partition plate or through a shelf-shaped tuning orifice in said partition plate, or Port means extending from any internal cabinet through any wall of the enclosure, or A plurality of port means extending from said second enclosure through said partition plate or other side wall, And passive diaphragm means mounted to said partition plate in place of said port means. The method of claim 1, The acoustic low pass filter is connected to the front of the drive to generate only low frequencies, A second enclosure disposed in front of the drive unit for providing a mass of air for an acoustic low pass function; Tubular or shelf port means are used to oscillate a particular range of low frequencies from the volume of air; Mechanical passive radiator means are used to oscillate a particular range of low frequencies from a new air volume. The method of claim 1, Horn means are used to couple the drive to atmospheric pressure; The horn shaped expansion diaphragm means couples the drive to the front of the embedded acoustic transmission line to increase its working distance or coverage. The method of claim 1, The drive unit is a flat type of flat panel drive unit for generating acoustic waves in two directions, Electrostatic acoustic panels for any frequency range, or Dynamic planar type acoustic panels for any frequency range, or Ribbon planar type acoustic panels for any frequency range, or A device with a two-way flat speaker design, which is a new general type of any type. The drive is mounted directly forward over the aperture of the appropriate diameter and faces the aperture and seals the acoustic transmission line embedded with the drive, First and second waveguides disposed directly in front of the drive around the fraudulent drive, the central apertures in the second waveguide and the radially conduit second waveguide to form a channel in a radially expanded manner from the center; First and second waveguides mounted at right angles to the first waveguide; A termination member disposed at the opposite end of the pair of waveguides to block the wave in the embedded acoustic transmission line, thereby causing the wave to reverse; An alternative density transmission medium fixed to at least one wall of one of the waveguides; And a loudspeaker driver of appropriate diameter and power operating capability mounted to the inlet of the embedded acoustic transmission line. The method of claim 6, And the aperture directs the wave by placing a compression plug mounted directly in front of the drive to maintain pressure deviation from the atmosphere by increasing the pressure on the drive. The method of claim 6, The rear side of the drive unit is coupled to the acoustic low pass filter to generate only low frequency, Acoustic low pass filters using port tubes and enclosures of appropriate diameter and length; or, And an acoustic low pass filter using an enclosure and shelf type tuning means formed from the enclosure, Wherein the acoustic low pass filter is a passive radiator diaphragm and an enclosure of appropriate diameter and volume. The method of claim 6, Multiple embedded acoustic transmission lines are used, each said enclosure dimension and volume being housed in a common large enclosure used for the lowest frequency or independently of each other, operating in each range. Different frequency ranges to optimize, Embedded acoustic transmission line enclosures, the dimensions of each of the embedded acoustic transmission line enclosures being adapted to a drive indicating a frequency range, A number of different dynamic transducers, in which different diameters of each of the transducers are appropriate for the frequency range, And a common housing for the plurality of embedded acoustic transmission lines that include the enclosure as a single subwoofer system. The method of claim 6, An alternative density transfer medium is an open cell urethane foam.

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