Speaker indicators

1. Rated impedance and impedance characteristics The rated impedance of the speaker system is generally determined by the rated impedance of the speaker unit used. The impedance characteristics of the speaker system are much more complicated than the impedance characteristics of the speaker unit. This is because the loudspeaker units used in the loudspeaker system are diverse, and the influence of the crossover network is added. The influence of the cabinet makes the impedance characteristics of the entire speaker system vary greatly with the structure type, the unit used and the frequency divider.

Second, the distortion characteristics of the distorted speaker system are more complicated than a single speaker. It is obtained by synthesizing the distortions of the various parts that make up the speaker system. These parts include: the distortion of each speaker that makes up the system; the standing wave in the cabinet and the vibration of the wall plate Distortion caused by the crossover network, etc.

3. Rated frequency range and effective frequency range The rated frequency range of the speaker system playback is specified in the product standard. The actual frequency range reached by the speaker system is called the effective frequency range. Ideally, the speaker system should reach the human ear audible frequency range of 16 ~ 20000Hz. In practice, the frequency range is generally designed at 40 ~ 20000Hz at home and abroad.

Fourth, the characteristic sensitivity level, the maximum output sound pressure level The characteristic sensitivity level of the speaker system is the same as that of the speaker under 1W input conditions, according to the national standard GB9396-88 (test standard), GB9399-88 (technical standard) specified at 1M from the speaker The measured sound pressure in decibels can be calculated from the characteristic output sensitivity level of the loudspeaker system.

5. Rated maximum noise power and rated long-term maximum noise power The rated maximum noise power of the speaker system refers to the maximum noise voltage that feeds the speaker system to the specified analog program signal within the rated frequency range without generating thermal and mechanical damage.

6. The pure tone speaker system should be free of mechanical sound, ringing sound, garbage sound, double tone, etc.

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Silica Soil Casting Parts

The first process of Investment Casting production is the manufacture of investment mold, investment mold is used to form the cavity in the refractory shell model, so in order to obtain the casting with high dimensional accuracy and surface finish, the investment mold itself should have high dimensional accuracy and surface finish. In addition, the performance of the melt itself should also make the subsequent shell making process as simple as possible. In order to obtain the above high quality requirements of the investment die, in addition to good pressure (pressing the investment die), but also must choose the appropriate mold material (referred to as the mold) and reasonable mold making process.

The advantage of the investment casting method is that it can cast complex castings of various alloys, especially high temperature alloy castings. For example, the blade of jet engine, its streamlined outer profile and cooling inner cavity, with machining process almost impossible to form. Investment casting process can not only achieve mass production, ensure the consistency of castings, but also avoid the stress concentration of residual blade lines after machining.

The biggest advantage of investment casting is that because investment casting has a very high dimensional accuracy and surface finish, so it can reduce the machining work, just leave a little machining allowance in the parts requiring higher parts, and even some castings only leave grinding and polishing allowance, without mechanical processing can be used. It can be seen that the investment casting method can greatly save machine tools, processing time and metal raw materials.

silica soil casting parts, Precise dimension

Tianhui Machine Co.,Ltd , https://www.thcastings.com