How to change the low-frequency resonance frequency (natural frequency) of a box speaker

What method can be used to change the low-frequency resonance frequency (natural frequency) of a box speaker

XDEC speaker think

The geometry of the cavity remains unchanged, and the resonance frequency can be adjusted up or down.

Doing the frequency spectrum debugging in the resonance box of the musical instrument, now I am doing the adjustment of the natural frequency inside a cavity in the low frequency range below 600hz. At low frequencies, it is not the structure but the air vibration in the cavity that resonates with the sound source. Make the helmhotz resonance model, the principle is the same as the sound pressure generated by the mouth of the bottle

Changing the volume (inverse ratio), changing the size (inverse ratio), and changing the material (inverse ratio of density) can all change the cavity's low-frequency resonance frequency.

Changing the quality, wall thickness, hardness, and shape of the cavity will change the resonance frequency, and it is estimated that the quality is the main factor.