Column speakers are generally used in some special places, such as background music in shopping malls, campus broadcasts in schools, gymnasiums and concerts, etc. They are all large occasions. Many units of the same size are used to improve the sound in the effective frequency band. Designed for pressure rating. So, what is the difference between column speaker and our ordinary speakers?
The sound column is a combination of multiple speakers connected in phase. The direction characteristic of the sound column is similar to that of a single speaker in the horizontal direction, but it is greatly improved in the vertical direction. It propagates in a wave pattern in the horizontal direction, but has a strong directivity characteristic in the vertical direction, forming a "plate"-like three-dimensional radiation effect.
Install the sound column near the stage entrance and point this "sound plate" towards the audience. The sound beam radiates to the back row of the auditorium with strong sound energy, while the front row is mutually affected by the phase difference caused by the different vertical distances of the speakers. Attenuation, the sound pressure may be lower than that of a single speaker, which makes the direct sound distribution of the sound field tend to be even. The horizontal direction of the sound column should not be "bunched", and there should be a large horizontal radiation angle, so that the sound field can be more uniform in the left and right directions.
Column speaker usually refers to 4 to 10 cone speakers arranged in a line. The feature is that when transmitting sound in the horizontal direction, the radiation angle of the speaker is the same as that of a speaker, while when transmitting sound in the vertical direction, the radiation angle of the speaker increases with the combination of speakers, especially when high-frequency sound , The sound beam can be transmitted in a certain direction.
The sound column speaker has a very effective vertical control effect. In an environment where the reverberation situation is more serious, the column speaker can effectively concentrate the sound to the listener, reducing the occurrence of rebound after reaching the wall.
The characteristic of the sound column is that it has a strong directivity in the vertical direction. The longer the sound column, the narrower the sound beam, the more concentrated the energy, and the stronger the directivity. When the length of the sound column is fixed, the higher the frequency, the narrower the sound beam and the stronger the directivity.
The best column speakers can be formed into multiple specifications according to different structures. The smaller the area of the "sound plate", the stronger the bunching effect, the sharper the directivity, and the on-axis sensitivity is much higher than that of a single speaker. The sound axis efficiency of the sound column on the main shaft is higher than that of a single speaker. Generally speaking, the more speakers that make up the sound column, the higher the sensitivity on the main axis and the farther the sound radiation distance.
Reasonable control of the suspension height and depression angle of the sound column can make the sound field more uniform and clear. Since the total rated power of the sound column is several times that of a single speaker, and the focusing effect in the direction of the sound axis, the sensitivity is doubled, which is more effective for long-distance sound reinforcement.
Compared with a single speaker, the low-frequency radiation efficiency of the sound column is greatly improved, thereby increasing the low-frequency response and enriching the tone. Using the directional characteristics of the sound column, placing the microphone outside the main sound beam (that is, the lightest sound in the up and down directions at both ends of the sound column), at the position with the weakest sound pressure, can improve the howling phenomenon and increase the sound transmission gain. In places where the reverberation time is long, the use of the sound column can greatly improve the clarity of the sound.
The directivity of the sound column weakens as the frequency decreases, that is, the directivity at low frequencies is very poor. Therefore, the vertical directivity of the sound column should be improved, that is, the directivity at high frequencies is weakened, and the directivity at low frequencies is increased. Usually, the sound column can be divided into high and low frequency bands and connected to a crossover network to make the long sound column emit low frequency sound, and the short sound column emit high frequency sound to improve its frequency response. Or use some common methods in important venues to separate the sound with a high-frequency horn speaker in the frequency band above 1KHz to improve high-frequency directivity and high-frequency sound.
In addition to the defects in the vertical directivity of the sound column that need to be improved by the above methods, the horizontal directivity also exists.
These problems can be solved with the help of a tone controller or equalizer. Lowering the volume of the bass frequency helps the speech sound to be clear, but it has a negative impact on music reproduction.
The installation angle of each speaker on a single speaker can also be based on the principle of sound wave diffraction, and the speaker hole on the sound column panel can be opened into a rectangular slit to improve the horizontal direction of the high frequency band.
As mentioned above, the sound column, as an important speaker device, is still widely used in many occasions.