RU31306U1 - Acoustic system - Google Patents

Description

Acoustic system

This utility model relates to high-quality floor-mounted speakers designed to emit sound as part of a home stereo or multi-channel complex of sound reproduction equipment.

Known speaker system for high-quality sound reproduction Linear Response 8.6 company Eltax (Germany), described in the article "Acoustic system Eltax Linear Response 8.6, published in the journal" Audio store. No. 3 for 2001, pp. 70 - 74. The system is assembled in three loudspeaker heads, of which two heads work in the range of low and among sound frequencies, and one reproduces the high-frequency part of the sound range. The use of two relatively small LF / MF heads instead of one larger size allowed the system designers to place it in a narrow high case (width 200 mm, height 835 mm), which helps to obtain a uniform frequency response of sound pressure. The low-frequency acoustic design of the system is a bass reflex. The cylindrical phase inverter pipe is brought out to the rear wall of the housing. The middle vertical ribs of the body are rounded to reduce unwanted reflections from them of the sound wave.

The disadvantages of the design include the following:

The outlet of the bass reflex hole on the rear wall does not allow placing the system close to the wall. The design does not provide for measures to reduce extraneous noise during the operation of the bass reflex. These noises, caused by air turbulence at the edges of the hole, can be very noticeable when listening at high fomkosti. In addition, turbulence reduces the efficiency of the phase inverter, which leads to a decline in the low-frequency part of the spectrum of the signal emitted by the system. The narrow case, being optimal from the acoustic point of view, at the same time makes the system unstable.

A known acoustic system according to the application of the Russian Federation ia invention No. 93014130, the abstract was published on 05.27.1995, the acoustic system contains a body in the form of a parallelepiped, standing on a small face, and the depth, width and height of the inner space of the housing are in the ratio 1: 1.05: 2 , 65. On the front panel of the housing are a bass reflex, a high-frequency head, a mid-frequency head and a low-frequency head. The phase inverter channel is made in the form of a pipe

IPC H 04R 1/28

rectangular cross section. On the rear panel of the housing there is a separation filter with an electrical circuit that allows you to distribute the input signal between the heads of the speakers in accordance with the frequency range of each head.

This speaker system, when executed in the floor version, is very cumbersome, which limits the possibilities of its use in domestic conditions. The design of the phase inverter channel does not provide for measures to increase efficiency and reduce noise during the operation of the phase inverter.

The closest set of features to the proposed utility model is the KVK 210 speaker system from Davis Acoustics (France). The acoustic system is described in the company's prospectus for 1999, p. 7. The speaker housing is made in the form of a rectangular parallelepiped, standing on a small face on the support spikes. The side ribs of the body are rounded. A high-frequency head, two heads for reproducing medium and low frequencies and an outlet opening of a phase inverter pipe are placed sequentially from top to bottom on the front face of the housing. The phase inverter pipe is round, expands to the outer end, providing a slight reduction in noise and an increase in the efficiency of the phase inverter.

With the help of a separation filter, the input signal is distributed between the heads so that one of the LF / MF heads reproduces only the low-frequency part of the spectrum, the other LF / MF head reproduces the entire range up to the frequency of coupling with the HF head. Such a construction of the acoustic system ensures the joint operation of both LF / MF heads at the lower frequencies of the sound range, while at the same time maintaining a uniform directivity characteristic at medium frequencies, characteristic of systems with one LF / MF head.

The width, depth and height of the body are in the ratio 1: 1.19: 4.3. The height of the casing (980 mm) is greater than that of other analogues, however, it still does not provide the correct arrangement of the working axis of the speaker.

The disadvantages of the system include:

The phase inverter pipe design, which expands only to the outer end, leaving a source of turbulence at the inner end;

The lack of stability of the system caused by the small footprint; All the analogues described above, being floor systems, have a height

heads. Thus, a common drawback of the systems considered is that their working axis passes significantly below the ear of a sitting listener. The optimal height of the working axis of the system is about 1 m.

The objective of the proposed utility model is to improve the quality of sound reproduction in real listening conditions. To achieve this goal in an acoustic system containing a body having the shape of a rectangular parallelepiped, standing on a small face on the support spikes, on the front face of which there is a high-frequency head, two heads for reproducing medium and low frequencies and an outlet opening of the bass reflex tube, sequentially the back face inside the housing is fixed electric separation filter having three outputs, each of which is connected to one of the loudspeaker heads, and the input signal is distributed by the filter in such a way that one of the two heads for reproducing medium and low frequencies reproduces only the lower frequencies of the sound spectrum, and the second reproduces the entire portion of the spectrum up to the frequency of docking with the high-frequency head, the housing is made with a size ratio of 1: 1.25: 5 ( width, depth, height), which led to an increase in the height of the body. To maintain the stability of the structure, a plate is attached to the lower edge of the body, the dimensions of which are larger in plan than the dimensions of the lower edge. In the corners of the plate fixed support spikes. In this case, the phase inverter pipe is made in the form of a body of revolution with a variable cross section, increasing from the middle of the pipe to its edges.

System separation filter - passive, LC type. The construction and calculation of such filters are described in the “Acoustics Handbook edited by M.A. Sapozhkova. M., Communication, 1979, pp. 187-189. The separation filter can also be made similar to the filter according to the application .f 93014130.

Thanks to the presence of new features, the quality of reproduction at the higher frequencies of the sound range for a sitting listener is improved due to the optimal location along the height of the working axis of the system, and at lower frequencies the quality of reproduction is improved due to the special construction of the reflex tube.

The proposed speaker system is illustrated by the drawings shown in FIG. 1 and 2.

The acoustic system comprises a housing 1 having the shape of a rectangular parallelepiped made of wood materials with a aspect ratio of 1: 1.25: 5, a loudspeaker head 2, 3, 4, a phase inverter pipe 5. A plate 8 is attached to the lower face 6 of the body. On the rear face a passive electric filter unit 7 is fixed inside the housing, which has one electrical input, which is the input of the speaker system and three outputs, each of which is connected to the corresponding loudspeaker head. Metal support spikes 9 are fixed in the corners of the plate 8.

In FIG. 2 shows a phase inverter pipe 5 having a flange 10 for fixing in a housing opening. The reflex tube may be made of plastic.

The speaker system works as follows.

An electrical signal is fed to the input of the separation filter 7, which includes a frequency range for each of the loudspeaker heads. An electrical signal from the filter outputs is supplied to the loudspeaker heads 2, 3, 4, which convert electrical energy into mechanical energy and emit sound into the surrounding space. When the acoustic signals of the heads 2, 3, 4 are added in air, a sound field is formed with spectral and temporal characteristics corresponding to the characteristics of the input electrical signal.

The narrow high case 1 of the speaker system made it possible to position its working axis, on which the most uniform frequency response of sound pressure is created, at the height of comfortable listening.

Sound radiation in the low-frequency part of the spectrum is amplified by an acoustic resonator, a bass reflex. The proposed design of the phase inverter pipe 5 provides a laminar flow of air flow in the pipe, which reduces unwanted noise and prevents a decrease in the efficiency of the phase inverter at high input signal levels.

Claims (1)

An acoustic system comprising a rectangular parallelepiped-shaped housing, standing on a small face on the support spikes, on the front face of which a high-frequency loudspeaker head is arranged sequentially from top to bottom, two heads for reproducing medium and low frequencies and an outlet hole of the phase inverter pipe, on the rear face inside the case a passive electric separation filter is fixed, having three outputs, to each of which one of the loudspeaker heads is connected, characterized in that to the lower th face plate is secured by its larger size, the support rails are secured in the corners of the plate, and the bass reflex tube is formed as a body of revolution with a variable cross-section increasing from the middle of the tube to its edges.