The design and production of ultra-low box should be based on the characteristics of the unit, and can be adjusted appropriately according to the listening style. In general, for those who listen more to DJ, they can choose a perforated box (with a larger low-frequency response), and the volume can generally be slightly smaller, in order to obtain a harder listening experience and fast low-frequency response speed. For those who mainly listen to human voices, they can choose a sealed box (with smooth frequency response and less distortion). Within a certain reasonable range, the larger the volume of the box, the lower the low-frequency diving. The smaller the volume, the smaller the low-frequency diving. The low-frequency is harder and the speed is faster.

The success rate of sealing box production is relatively high, with low distortion, making it a good choice. If the volume is too large and the damping of the horn is insufficient, it is easy to lose control, and low-frequency distortion will increase. The buzzing statement indicates that the sound base is not clean, and the basin body is under damped, causing excessive uncontrollable movement, and low-frequency is easy to drag. If it is a perforated box, in addition to its volume and shape, there are also issues with the design of the inverted phase tube. If the diameter of the tube is too large or too small, too long or too short, it will affect the low-frequency performance. The box should be designed as sturdy as possible, and attention should be paid to using sound-absorbing cotton to reduce standing waves and counteract the energy inside the box, to avoid low-frequency noise. The sound-absorbing cotton can effectively reduce the resonance peak of the box, and can effectively move the resonance peak to a lower frequency, making the listening experience better.