If self-made speakers find that the sound quality is still lacking, you can test and adjust them from the following aspects:
1. Check for leaks
Insufficient bonding between the cabinet plates, rough processing of the counterbore surface of the cabinet, uneven inclination, or no gasket on the junction box, speaker unit and cabinet counterbore, will cause sound leakage. To find the method, you can use a piece of thin paper to put on the box frame, junction box, and the joint between the speaker and the box when the speaker is working. If the thin paper is found to be blown, it means that there is a leak. If there is leakage at the junction of the box, you can apply adhesive to the inside. If the leakage is in the junction box, the connecting surface of the loudspeaker and the box body, the surface of the counterbore should be smoothed and pad with rubber of appropriate thickness.
2. The bass is soft, lacking in dynamics and a little muddy.
This may be caused by the loudspeaker being in an over-damped state. Appropriately increase the sound-absorbing material in the cabinet, or appropriately shorten the length of the phase inversion hole.
3. Lack of anger, can't make bass
By reducing the sound-absorbing material, the length of the inverted tube can be lengthened appropriately, or an appropriate amount of sand can be poured into the box.
4. The sound is too noisy and the sound image is unnatural
It may be that the sensitivity of the mid or high frequency unit is too high, making the speakers sound noisy. If this is the case, a certain attenuation resistance can be added to the corresponding unit frequency division network. If you feel that the low-frequency and high-frequency units are sounding separately, especially if you feel that the sound jumps between the two units near the crossover point, it may be that the polarity of the speaker unit is reversed.