1. Closed Enclosure is the simplest and most commonly used speaker in structure. It is a sealed box after installing the speaker, and its main function is to isolate the sound wave that we do not need. This speaker is suitable for speakers smaller than 10 inches in diameter.

Why do we need to make a box for installing subwoofers? What is the relationship between the two- Driving

The advantages of a sealed speaker are: easy to make, easy to master, and powerful sound. The disadvantage is: low efficiency, with 50% of the energy consumed in the speaker.

2. Bass Reflex Enclosures are also known as inverted or breathable reflex speakers. On the basis of a sealed speaker, a sound hole is opened on the panel and a tube (inverted tube) is pressed inside the sound hole (inverted hole). Its function is to invert the phase of the sound wave inside the speaker by 180 degrees and send it out through the inverted hole. The frequency and phase of this sound wave and the sound wave outside the speaker are consistent, and the combination of the two increases the low-frequency power and utilizes the wasted energy in the sealed speaker. Suitable for bass speakers with a diameter of 12-18 inches.

The advantages of an inverted speaker are high efficiency, deep submergence of the sound basin, and the ability to replay low-frequency signals as low as 20Hz. The disadvantage is that the opening position of the inverting hole and the diameter and length of the inverting tube need to be carefully calculated, otherwise it will affect the low-frequency playback effect; There are high requirements for the technical quality of design and production personnel; Moreover, there are many uncertainties in the reflected sound waves inside the inverted hole, resulting in unstable sound generated.

Why do we need to make a box for installing subwoofers? What is the relationship between the two- Driving

The larger the volume of the box, the deeper the low-frequency diving, and the Q value decreases accordingly. But after low frequencies, one becomes weak and should throw sandbags into the speaker.

The smaller the volume of the box, the better the low-frequency force, and the higher the Q value. But the resonance frequency of the relative speaker is about to rise, and at this point, more sponges can be added to expand the inner product.

The longer the inverted tube, the better the transient characteristics of the speaker. At the same time, the lower the low-frequency dive (although the volume may decrease). However, if the inverted tube is too long, the sound will drag and the transient characteristics will deteriorate. If the inverted tube is too close to the board inside the box, it will also produce airflow sound, which is necessary.

The shorter the inverter, the worse the transient characteristics, and the higher the resonant frequency (but with an increase in inductance).

It can't be said that the speakers with inverted holes are better than those without inverted holes. It can only be said that the conversion efficiency of inverted speakers is higher than that of closed speakers. Theoretically, the fidelity of closed speakers is higher than that of inverted speakers, because the inverted speakers add resonance sound to the box and have sound pollution.

The best sound restoration in theory should be the speaker mounted on an infinitely large flat baffle, which provides the most realistic sound restoration.

Adding inverted phase holes effectively increases the volume of the box, reduces the resonance frequency of the box, and effectively expands the low-frequency diving. However, the frequency response curve of speakers with inverted phase holes is not as flat as that of enclosed speakers. Typically, high-end monitoring level speakers use a closed design, while civilian level speakers usually have inverted phase holes.

Under the same volume, speakers with inverted holes can achieve lower frequency response, but closed speakers have a more authentic sound quality restoration.