The principle of virtual surround sound

　　The key to the realization of virtual Dolby surround sound is the virtual processing of sound. According to the principles of human physiological acoustics and psychoacoustics, the surround channel is specially processed to create an phantom feeling that the surround sound source comes from the rear or side of the listener. Several effects of the principle of human hearing are applied. Binaural effect. British physicist Rayleigh found through experiments in 1896 that two human ears have time difference (0.44-0.5 microseconds), sound intensity difference and phase difference to the direct sound of the same sound source, and the hearing sensitivity of the human ear can be determined according to these tiny The difference can accurately judge the direction of the sound and determine the position of the sound source, but it can only be limited to determine the sound source in the horizontal direction in front, and cannot solve the localization of the three-dimensional empty sound source. Auricle effect. The human auricle plays an important role in the reflection of sound waves and the orientation of spatial sound sources. With this effect, the three-dimensional position of the sound source can be determined.

　　The frequency filtering effect of the human ear.

　　The sound localization mechanism of the human ear is related to the sound frequency. The bass of 20-200 Hz is located by the phase difference, the midrange of 300-4000 Hz is located by the sound intensity difference, and the treble is located by the time difference. According to this principle, the differences in language and musical tones in the playback sound can be analyzed, and the surround feeling can be increased through different processing. Head related transfer function. The human auditory system produces different frequency spectra for sounds in different directions, and this spectral characteristic can be described by the head-related transfer function (HRT). To sum up, the spatial positioning of the human ear includes three directions: horizontal, vertical, and front and rear. Horizontal positioning mainly relies on both ears, vertical positioning mainly depends on the ear shell, and front and rear positioning and the perception of the surround sound field rely on the HRTF function. Based on these effects, virtual Dolby surround sound artificially creates the same sound wave state as the actual sound source at the human ear, so that the human brain produces a corresponding sound image in the corresponding spatial orientation.

　　Reasons and troubleshooting methods when the power amplifier fails

　　As the most basic part of the audio system, the power amplifier is also the equipment that is most prone to failure. Let JSL audio manufacturers summarize for you how to do the basic troubleshooting when the power amplifier fails:

　　Check whether the power line is connected to the fuse, whether the power line is broken or the fuse is in poor contact, and the fuse is blown → that is, check whether the rectifier bridge or electrolytic components of the power amplifier rectifier power supply are damaged, such as the rectifier diode or bridge stack. Check other circuits, such as power amplifier tubes, etc.

　　Signal level indicator blinks normally, but no sound output

　　First check whether the speaker unit is normal. If it is normal, check whether the speaker leads are normal, that is, check that the terminals are in good contact. Normal, that is, open the case and visually check or listen to whether you can hear or see whether the output relay is pulled in. If the pull-in is normal, (If there is a multimeter), it is to measure whether the front input end and output end of the relay are connected directly.

　　The power light indicates that there is no sound output, but the sound of the output relay is heard.

　　First, use a multimeter to measure whether the power supply of the power amplifier is normal. If it is normal, the signal line terminal of the signal input end is connected with the hand. If a loud current sound is heard, it is initially judged that the power amplifier part is basically normal, that is, the signal is shaken slightly. Check whether the lead wire is faulty or in poor contact. If it is in poor contact, use a multimeter to measure whether the wire is faulty and deal with it normally.

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