There are many varieties of speakers, such as electric speakers, lingual reed speakers, crystal speakers and excitation speakers. Among them, the reed speakers and crystal speakers were used more in the cable broadcasting system in the past, and now they are basically no longer used. The most widely used and numerous are electric speakers.
 The speakers are classified according to the working frequency bands:
① High-pitched speaker: specially replay the high frequency part of the audio signal output by the power amplifier, its operating frequency range is generally 2.5-25kHz.
② Medium tone speaker: specially replay the medium frequency part of the audio signal output by the power amplifier, the operating frequency range is generally 500-7500Hz.
③ Bass speaker: compared with high and medium speakers, the low frequency speaker is specially replay the low frequency signal, and its operating frequency is generally 15-5000Hz.
④ Full frequency band speaker: refers to the working frequency can cover the audio high, medium and low full frequency band.

 According to the shape of the speaker vibration film,
① Conical vibration film: the performance is relatively stable, allowing the amplitude of vibration is larger, it is easier to make a large caliber speaker, almost all the speaker medium and bass units are conical vibration film speaker.
② Flat plate vibrating film: the radiation surface is concave, which further improves the range of loudspeaker piston movement compared with the conical vibration film.
③ Spherical dome shape vibration film: its diaphragm is hemispherical dome shape, its playback sound directivity is wide, good transient response, phase distortion is also small, mainly used for the production of tweeter speaker. The vibration system in the speakers has a great influence on the quality of the playback sound, so the composite vibration film has been widely used in the modern speakers, which is composed of different materials. Table 12-4 lists the performance comparisons of the different vibrating membrane speakers.

 Speaker according to the external shape of the round, oval and ultra-thin several. Oval speaker is mainly to facilitate the design of the whole machine shape and internal structure, its electrical performance and with the same material, the same principle of the same caliber of the circular speaker is basically the same.

 According to the magnetic circuit structure, there are external magnetic, internal magnetic, shielding and dual magnetic circuit and other forms, among which the latter three forms of speaker magnetic leakage is very small, suitable for TV, combined sound and other electronic machines with high requirements for stray magnetic field. Moreover, the dual magnetic circuit speakers have a high sensitivity.