The phase of an announcement speaker is the connection of the positive and negative poles of the loudspeaker when used in series and parallel. When more than two speakers are used, the consistency of the audio current direction of the loudspeaker must be ensured so that the vibration direction of the speaker's paper basin is maintained, and the energy of the air vibration is not counteracted, thus not to reduce the playback effect. In order to achieve this requirement, the positive pole of one speaker is connected to the negative pole of another speaker when used in series. In parallel, the positive poles of each speaker are connected, and the negative poles are connected, which means that the requirement that the phase must be the same is reached. However, some announcement speaker system does not mark the words of positive and negative poles on their pins, which affects the use of series and parallel connections, so we have to determine the positive and negative poles of the speaker.
The methods are as follows:
1) put the multimeter in the lowest gear of the DC current gear, connect the two pins to the speaker, and then press the paper pot of the loudspeaker lightly and quickly, and watch the direction of the pointer of the multimeter in time, if the pointer is to the right, and then the red pen is connected to the positive pole and the black pen is connected to the negative pole. When the needle is left swinging, then the red pen is connected to the negative pole, and the black pen is connected to the positive pole. Use the same method and polarity rules to detect other speakers and do the marking, so that they can be in the same phase after series and parallel connection.
2) use one or two batteries (Series) to connect the positive and negative poles of the battery to the two pin of the loudspeaker, and observe the vibration direction of the paper basin in a timely manner when the power is connected. If the paper basin moves towards the direction of the magnet, the negative electrode of the battery is connected to the positive pole of the speaker. Then exchange the battery connected to the two pin of the loudspeaker, and the paper basin moves outwards, which indicates that the positive pole of the battery contacts the positive pole of the speaker.