This paper mainly discusses the key of multi-function hall sound system under three debugging modes: conference mode, performance mode and cinema mode.
Several problems in hall design
Left-right as far as possible to use the same brand, the same model of products, three channel configuration is basically the same; Before commissioning: confirm the connection of the system and the specific distribution of each sound channel;
Debug key points in conference mode
1, the multi-function hall generally belongs to the podium meeting, non-round table meeting, and the same as the lecture hall;
Audience clarity and sound transmission gain are two important indicators. If the sound transmission gain is higher, the system can obtain a higher gain, otherwise the clarity is not high.
3. Objectively explain the screaming problem to Party A or the user;
4, the role of the auxiliary speaker is indispensable;
5, the main sound reinforcement and auxiliary speakers need to be adjusted separately;
6, the front of the rostrum must have a sound amplification box, the main speaker is prohibited to radiate to the rostrum area;
7, as far as possible to control the number of microphone open at the same time has a decisive effect on the suppression of whistling;
The pressure limit of the conference system is more conservative than any other value, usually when the power amplifier is configured, the processor pressure limit startup threshold is low, generally between -10 and -20 dB, the speed is generally 1-- 5 ms, it is recommended to take the compression ratio: 10:1 to infinity;
9, the lecture hall generally has multimedia playback function, so the main spread spectrum frequency band can not be set too narrow, it is recommended between 40Hz-----18KHz. If it is not replayed but only a simple language amplification, the frequency response range can be greatly reduced, and it can be set between 100-12 K.
10, the conference microphone low cut function is recommended to open in the mixer, so that the low frequency will not enter the subwoofer system, will not cause low frequency feedback;
All parametric or graphical equilibria are used as feedback suppression. Recommended if the advanced matrix processor has feedback suppression. In addition, its bypass can be disabled;
12, noise door use precautions;
13, the microphone balance adjustment of the mixing table;
14, preferably a return system.
Sound transmission gain is directly related to sound field layout, microphone directivity, environmental structure and sound absorption (frequency characteristics of sound field), and frequency characteristics of speaker and microphone.
Performance mode debugging key points
1. Check the key points of performing arts system debugging in detail (please follow XYCAD official wechat for subsequent uploading);
2. In addition to the immovable arrangement of the speaker in the multi-function hall, the meeting and performance are almost the two most opposed modes: power, sound pressure level, frequency characteristics, microphone, timbre, various parameters of gain at all levels, pressure limit, stereo sound, effect and so on are almost completely different;
3. Feedback inhibition is ineffective;
4. The callback must be performed.
Cinema mode debugging key points
Cinema mode is a relatively simple mode, because it does not need too much modification, and the first principle is to truly restore the dynamic and sound of the film.
2, no microphone, do not return the phone two problems;
3, left, middle, right, left circle of audio image positioning debugging;
4, ultra-low frequency lower limit, full frequency upper limit as far as possible not to do low, high resistance values, in order to truly restore the movie signal. The very low signal can be composed of two main frequency channels, and can also be made into stereo co-channel and left and right full frequency combination. You can also use the decoder with its own ultra-low signal;
Note the filtering Settings for each speaker frequency range;
6, frequency characteristics can be balanced according to movie standards (combined with sound field testing); Schedule standard.
7, surround speaker and main speaker sound pressure level can not be too big difference, which is easy to ignore. Otherwise, it is recommended to take a multi-point uniform distribution in the design, which can improve the overall sound pressure level, without making the surrounding audience sound pressure level too large;
8. Setting of pressure limits. The compression rate should not be too large, so as not to destroy the dynamic of the original film, while taking into account the security of the system;
Use noise gate with caution;
10. The pattern cannot be resolved.