In the performance, the sound needs to be constantly adjusted, and the effect of the surrounding class should be adjusted. It is better to let us see the adjustment method of the surrounding effect in the performance, so as to have a better sound in the performance in the future. prepare.
Reverberation adjustment
The audience gets the sound directly from the sound source. The propagation attenuation of the sound pressure level is inversely proportional to the square of the distance. That is, the distance is doubled and the sound pressure level is reduced by 6 dB. It has nothing to do with the sound absorption characteristics of the room.
Near-reflex sound (early reflection sound) Eary Refections passes through the surrounding interface once or twice. The sound that reaches the audience after reflection. The time delay between the recent reflected sound and the direct sound is 30ms. The human hearing can't distinguish the direct sound or the near sound, and they can only be superimposed together. The near-reflected sound is beneficial to improve the pressure level and clarity. And related to the sound absorption characteristics of the reflective interface.
Late reflection sound (reverberation sound)
The reflections that are later than the direct sound to more than 30ms are claimed to be late reflections (reverberation), and the reverberation can help people identify the closed space characteristics of the room (the size of the room). For music programs, the fullness of the music can be increased. It provides a beautiful and pleasant component and has a masking effect on the near-reflected sound, which affects the clarity of the sound and the intelligibility of the language. Therefore, this ingredient must not be absent, nor should it be too large. The size of the reverberation sound is related to the sound absorption characteristics of the surrounding interface, and is usually expressed by the mixed time RT.
Reverberation time
When the sound source reaches steady state, the sound pressure level of the room is attenuated by 0 dB after the sound is stopped.
Sound field effect
The sound field effect is mainly to simulate the sound effects propagating in a room of different volume, body shape and sound absorption conditions.
The parameters of the sound field effect are mainly: the reverberation time RT, the delay time, the sound diffusion and the density of the reflected sound.
Reverberation time adjustment
The length of the reverberation time gives the listening effect of the room size. The length of the reverberation of the effect can be determined by the following factors:
In a room with a large volume and insufficient sound absorption, the artificial reverberation time of the effect is short.
The reverberation time should be shorter when the low frequency is more than the full tone; the reverberation time can be longer when the high frequency is sufficient.
When the ambient noise is large, the reverberation time can be appropriately lengthened.
When the effect sound volume is large, the reverberation time can be adjusted to be shorter.
Pre-delay adjustment
The pre-delay is the interval at which the echo (Echo) of the effect is controlled. The echo is a phenomenon when the time difference between the same sound arrives more than 50Ms. When the Pre Delay is less than 0.1 second, the delayer becomes a reverberator, which can imitate the early reflection sound effect, making the sound thicker and heavier.
Feedback rate of echo effect (Feed back)
This parameter controls the number of echoes that can be adjusted from 0% to 99%. At the most, an endless echo will be formed, so it is generally adjusted to about 30%.
Phasing phase shifting effect
Mixing the delayed sound with the undelayed sound. Since the two sounds have a time difference (phase difference), the selected peaks will be added at certain frequencies to form peaks, while other frequencies are mutually The frequency characteristics of the "comb filter" are formed by offsetting the valley point, and the position of the peak and valley of the characteristic of the comb filter effect can be controlled by adjusting the delay parameter, and the mixing ratio of the delay signal of the direct signal can be adjusted. The difference between the peak and valley of the comb filter characteristic. When the ratio of the two is 1:1, the peak-to-valley difference is the largest, reaching 6dB. The delay amount of the transplant effect should not be over-fired and adjusted between 1ms and 20ms.
Flange chrome effect
The effect of modulating the delay time (the delay varies according to a certain law). This effect can reciprocally exaggerate the amount of odd or even harmonics in the sound, causing periodic changes in the spectral structure of the sound. Thus, illusory sound effects such as "empty sound", "jet sound" and "alternative sound" appear. The adjustment parameters of the Flange effect are modulation frequency, modulation depth, and feedback rate. Mainly used for special sound processing occasions, should be used with caution
delay:
Delay: 3-35ms will produce a "comb filter" effect, which is the Flange effect;
35-50ms will produce Chorus chorus effect;
More than 50ms will produce Echoes echo effect;
Low-frequency modulation (AM, FM) of the source signal can be processed into a vibrato effect.
Reverberation time:
Too little 0.5 seconds: the sound is dry and thin;
1.9 seconds for the language: high definition, clean sound, but the music is not full;
1.2 seconds for music: the sound is warm, full, discouraged, with a sense of space and concentration, vivid and bright;
Too much 2 seconds: the voice is turbid, there is echo, snoring and distant feeling.
Relationship between hearing and sound pressure level
Low volume: weak sound, thin, dynamic, low bass, high pitch
Moderate volume: natural, clear, soft, full of body
When the volume is too loud: the sound is full and powerful, dynamic, but not soft, the sound is hard.
The optical network unit (ONU) is a terminal device for optical fiber access. It should be used in conjunction with an OLT (Optical Line Terminal). The OLT generally stores the central computer room of the ISP.
The optical network unit is an optical fiber termination device in the optical fiber access network, which provides multiple service interfaces to users. It has an optical interface on the network side and an electrical interface on the user side. Therefore, the optical network unit (ONU) needs to have the functions of optical/electrical conversion and electric/optical conversion, as well as digital/analog and analog-to-speech signals. /Digital conversion function and multiplexing, signaling processing and maintenance management functions.
Generally speaking, the functions of the optical network unit mainly include the following items
1. Choose to receive the broadcast data sent by the OLT;
2. Respond to the ranging and power control commands sent by the OLT; and make corresponding adjustments;
3. Buffer the user's Ethernet data and send it to the upstream in the sending window allocated by the OLT
Industrial Onu,Industrial Grade ONU,Epon 24Fe Onu,Industrial Grade Outdoor Metal ONU
Shenzhen GL-COM Technology CO.,LTD. , https://www.szglcom.com