1. The resonance frequencies of the three are different
(1) Closed speaker: The existence of a closed box increases the rigidity of the speaker's motion quality to produce resonance, eliminates the acoustic short circuit and interference phenomenon before and after the speaker cone, so that the lowest resonance frequency of the speaker rises and the tone is more pure.
(2) Inverted speaker: It can further expand the lower limit frequency of low-frequency balanced playback without decreasing the sound volume. Ideally, the lower limit of the low frequency playback frequency can be as much as 20% lower than the speaker resonance frequency.
(3) Labyrinth speaker: It has a slight damping and tuning effect, which increases the sound output of the speaker near or below the resonance frequency, and reduces the amount of stroke while enhancing the bass output.
2. The internal structure design of the three boxes is different
(1) Airtight speaker: Install the speaker unit in a fully sealed box.
(2) Inverted-phase speaker: A cylindrical inverted hole is designed on the front of the speaker to allow the air to circulate inside and outside the box.
(3) Labyrinth sound box: The sound duct in the sound box is in a labyrinth shape, and the cross-sectional area of the sound channel is generally equal to the effective area of the diaphragm of the speaker unit. At the back of the loudspeaker, there is a sound tube made of sound-absorbing wall panels, the length of which is 1/4 or 1/8 of the wavelength of the low-frequency sound that needs to be boosted.
3. The three have different uses
(1) Airtight speakers: the most common structure in low- and mid-range speakers, mainly used for home audio.
(2) Inverted-phase speaker: The volume is large, some even reach 2 cubic meters, and there are several inverted holes on the panel. Often used in broadcasting.
(3) Labyrinth speaker: commonly known as a subwoofer, the speaker is invisible, and there is only one hole. Its speaker is installed inside the speaker with several layers of partitions. Commonly used in portable speakers and car audio.