For various speakers, the requirements for the quality factor of the low-frequency speaker-Q0 value are different. For closed boxes and inverted boxes, the Q0 value is generally between 0.3 and 0.6. Generally speaking, the larger the caliber, magnet and voice coil diameter of a low-frequency speaker, the better the low-frequency reproduction performance and transient characteristics, and the higher the sensitivity. The structural form of the woofer unit is mostly cone type, and a small amount is flat type. There are many types of diaphragms for bass units, including aluminum alloy diaphragms, aluminum-magnesium alloy diaphragms, ceramic diaphragms, carbon fiber diaphragms, bulletproof cloth diaphragms, glass fiber diaphragms, acrylic diaphragms, paper diaphragms, etc. Bass units that use aluminum alloy diaphragms and glass fiber diaphragms generally have smaller diameters and can withstand greater power, while woofer units that use reinforced paper cones and glass fiber diaphragms have more accurate timbres when replaying music and have good overall balance.
Q0: The quality factor of the speaker unit is a very important parameter that must be understood before designing and making speakers. On the impedance characteristic curve of the speaker unit, it represents the sharpness of the impedance peak of the impedance curve at the resonant frequency. It reflects the damping state of the speaker vibration system to a certain extent, referred to as the Q0 value. The higher the quality factor of the speaker unit, the higher the quality factor of the speaker unit. The resonant frequency is more difficult to control. The low-frequency characteristics of a speaker are usually determined by the quality factor value and the resonant frequency of the speaker unit, where the size of the quality factor is related to the sound pressure output by the speaker unit at the resonant frequency. When the Q0 value is too low, the output sound pressure of the speaker drops rapidly before it reaches F0, and the speaker is in an over-damped state, resulting in excessive low-frequency attenuation. When the Q0 value is too high, the speaker is in an under-damped state and the low frequencies are excessively enhanced. The larger the Q0 value, the steeper the peak. Therefore, we say that the quality factor of a speaker cannot be too high or too low. Usually, we take its critical damping value Q0 to be equal to 0.5-0.7 as the best value range.
