For a variety of different speakers, the quality factor of low-frequency speakers-Q0 value requirements are different. For closed and inverted boxes, the Q0 value is generally between 0.3 and 0.6. In general, the larger the caliber of the low-frequency speaker, the diameter of the magnet and the voice coil, the better the low-frequency playback performance and transient characteristics, and the higher the sensitivity. The structure of the woofer is mostly cone type, and a small amount is flat type.

There are many types of woofer diaphragms, such as aluminum alloy diaphragm, aluminum magnesium alloy diaphragm, ceramic diaphragm, carbon fiber diaphragm, bulletproof cloth diaphragm, glass fiber diaphragm, acrylic diaphragm, paper diaphragm, etc. Bass units that use aluminum alloy diaphragms and glass fiber diaphragms are generally smaller in caliber and bear more power, while bass units that use reinforced paper cones and glass fiber diaphragms have a more accurate sound when replaying music and have a good overall balance.

The quality factor of the speaker unit is an important parameter that must be understood before designing and manufacturing the speaker. On the impedance characteristic curve of the speaker unit, it means that the sharpness of the impedance peak of the impedance curve at the resonance frequency reflects the damping state of the speaker vibration system to a certain extent, referred to as Q0 value, the higher the quality factor of the speaker unit, The more difficult the resonant frequency is to control.

The low-frequency characteristic of a speaker is generally determined by the quality factor of the speaker unit and the resonance frequency, where the quality factor is related to the sound pressure output by the speaker unit at the resonance frequency. When the Q0 value is too low, the speaker's output sound pressure drops quickly before reaching F0. The speaker is in an over-damped state, which causes excessive low-frequency attenuation.

When the Q0 value is too high, the speaker is under-damped, and the low frequency is excessively strengthened. The greater the Q0 value, the steeper the peak. Therefore, we say that the quality factor of the loudspeaker can neither be too high nor too low, usually we take its critical damping value Q0 equal to 0.5-0.7 as the best value range.