1、Jindingsaisi company is focused on the field of acoustics. At present, there are a number of acoustic related patents and invention patents to ensure our company's technical lead in the field of acoustics.

The company's products in the wedge, soundproof door, ventilation system, damping system, sound-absorbing ground, its products are not only superior performance, price concessions, and beautiful appearance, environmental protection materials, products exported to the United States, Singapore, Russia, India, Japan, Taiwan and other countries and regions, and strictly comply with environmental performance requirements of EU and North america.

1.Type of anechoic room                                                                                                                         

* The whole noise room, the semi anechoic room and the simple anechoic room

Type of sound absorbing materials

* Glass wool metal wedge plate wedge anechoic chamber

Type of sound insulation board

* Mixed brick building structure, metal sound insulation sound absorption plate

Type of vibration isolator

* Spring isolator, rubber isolator

Type of ground net of full acoustic chamber

* Steel wire net, reinforced hard ground net

2. The function of the anechoic room

It is mainly used for the precision test of automobile, mechanical and electrical, electrical appliances, communication products and other standard experiments.

3. The size of the anechoic room:

For example: outside 5600mm*3200mm*4500mm,

Internal 3000mm*2500mm*3000mm.

4. Performance of anechoic room:

For example: the background noise is less than 5dB, and the cut-off frequency is 80Hz.

5. Characteristics of anechoic room:

The standard acoustic free field space is used for precision acoustic testing, and third party detection and calibration reports are issued.

The anechoic room (semi anechoic room) is an indispensable test environment for all kinds of noise testing and acoustic research. Jinding Seth company has inherited many years' research achievements in the field of acoustics, and combined with its practical experience in engineering, we have designed and built several distinctive anechoic rooms in China.

Design

After a full understanding of the customer's needs, the Jinding Seth company designed the sound - down room according to the standard. The acoustic targets in the design include the background noise, the cut-off frequency, the available space and the vibration damping. In order to meet the acoustic parameters, design considering the convenience of use, wedge gate, specimen (product) installation and handling, ventilation, instrument line, monitoring conditions, indoor environment etc.. Every anechoic room designed by the Jinding Seth company is a fine quality interior decoration.

Construction

In the process of construction, the company strictly controls the selection of materials to ensure that indoor environmental pollution meets the requirements of the national standard.

Basic concepts of an anechoic room (or a semi anechoic room)

Free field space

The main function of the anechoic chamber is to provide a free field space or a semi free field space for the acoustic test. The free field refers to the acoustic wave propagation in infinite space, there is no reflector and reflector.

In nature, the free field space is to hang the sound source in the air, away from any reflection, and the sound wave can be freely propagated to the 360 degree angle. The semi free field space refers to a full reflection surface in the free space, and the sound wave can only be propagated freely in the direction of the 180 degree hemisphere. A half free field, such as a large open parking lot, an outdoor basketball court, a apron... Etc..

Waves propagate a specific physical definition in a free field or a semi free field.

(1) The sound pressure of the point sound source attenuates with the distance, which is the inverse square law of the sound energy.

(2) The sound pressure level is equal to the sound intensity at normal temperature and atmospheric pressure. This is the theoretical basis for measuring sound power in an anechoic chamber.

Background noise

In spite of the large open-air parking lot, outdoor basketball court, apron... It can also provide a half free field space, but the measurement will be influenced by the background noise. It is impossible to measure the noise of the refrigerator by measuring the noise of the refrigerator at 30dB (A) and the ambient noise in the environment at 45dB (A). Therefore, the other function of the anechoic room is to provide a low background noise environment to meet the requirements of the test environment.

According to the national standard GB6882 - 86, the sound power level of the acoustic noise source is measured, and the anechoic chamber and the semi anechoic room precision method > >, in the test frequency range, the background noise's sound pressure level is at least 6dB lower than the sound pressure level of the measured source, preferably lower 12dB.

Cut-off frequency

The noise reduction room is to simulate the free field or semi free field space in the room, so the sound absorption coefficient of the wall is more than 99%. The reflection coefficient of the ground in the semi free field is more than 95%. It is impossible to design a 100% sound absorption body that can achieve a full band (20 Hz - 20000 Hz). Because the general materials of high frequency sound waves can easily be absorbed, and the low frequency absorption and the thickness of the material (the length of the wedge). The cut-off frequency is above the frequency, and the sound absorption system of the wall can guarantee the sound absorption coefficient of 99%. In practical engineering (semi) free space refers to sound waves above the cutoff frequency, anechoic chamber (semi) for free space, the cut-off frequency is lower, the greater the length of wedge. In general, the length of the wedge for 1/4 wavelength theory.

Identification method of anechoic room

In practical engineering, the free space of sound field is the key basis for identifying the good or bad of the noise cancellation room. GB ISO 4744 GB and GB 688286 provides a method for identification of anechoic chamber free space.

In addition, the background noise is another important indicator of the anechoic chamber. The background noise obtained in the measurement is the background noise of the instrument and the background noise of the anechoic chamber.