Characteristics of various speaker cabinets

1. The most classic sealed box,
which evolved from the concept of infinite panels and changed the drawback of energy waste behind the speaker cone caused by infinite panels, so that the speaker can work in a relatively small volume, but it is still inefficient. The advantages of this box are small size, minimal sound coloration, slow low-frequency roll-off, and low distortion! Usually this type of box is equipped with a soft cone speaker (basically equal to high Q). The key point of making this box is to pay attention to the sealing of the box!

2. Bass reflex type (commonly known as phase reflex type in China)
This is the most common box. Its advantages are moderate size, medium efficiency, and good sound quality in a wide frequency band. Its disadvantages are muddy low frequencies and too fast roll-off! (Not suitable for low-frequency hifi playback) The secondary phase reflex type is a form of enhancing the bass reflex effect. The enhancement effect of low frequencies is improved, but it also causes a deep valley in front of the low-frequency peak, and the effect of low-frequency muddiness and distortion is also increased! It is difficult to make and adjust.

3. Open back (OB ) is the most common box for electric guitars. It requires a speaker with a harder cone. The advantage is that it is easy to make, but the disadvantage is that it lacks low frequency. When making this box , be careful not to make the side panels too deep, otherwise there will be resonance.

4. Transmission Line and Acoustic Labyrinth This type of box is often large in size. The sound waves behind the speaker are put into a pipe several meters long and fed back. The pipe is often folded, and a large
amount of sound-absorbing material is used inside to absorb all sounds except low frequencies to reduce distortion. The low frequencies come out from the opening of the pipe and are in phase with the sound from the front of the speaker. The characteristic is that the low frequencies are strengthened while the quality is quite good.

5. Rear Loaded Folded Horn 4. Transmission
Line and Acoustic Labyrinth This type of box is often large in size .
The sound waves behind the speaker are fed back through a pipe several meters long. The pipe is often folded, and a large amount of sound-absorbing material is used inside to absorb all sounds except low frequencies to reduce distortion. The low frequencies come out of the pipe opening and are in phase with the sound from the front of the speaker. The characteristic is that the low frequencies are enhanced while the quality is quite good.

5. Rear Loaded Folded Horn In the horn
box, the sound passes through a cavity with a continuously expanding cross-sectional area, the energy is amplified, and the directionality is strengthened. The difficulty in making the horn is at the junction of the unit and the horn, and it is necessary to prevent distortion caused by reverberation and resonance. Sound coloration is also a problem. The low-frequency horn is huge, and the advantage of the right-angle folded horn is that it is compact enough. The disadvantage is that it suppresses the high frequency and causes its distortion. This box still uses the front sound of the speaker to output directly. Although the efficiency is higher than that of the reflex box, it is still the lowest efficiency low-frequency horn box!
6. Front Loaded Straight Horn This type of box has extremely high efficiency and directivity! Commonly used in large occasions such as stadiums. But it is not suitable for lower frequencies because it will require a large volume and length. In addition to the previous two points, the advantages also include small sound coloration, good sound transients, and high resolution. In hifi, it is often used in mid-high frequencies and requires a compression driver.

7. Front Loaded Folded Horn The classic W - Bin horn box is of this type. Its advantages are high efficiency and compact structure! Its disadvantages are narrow bandwidth and large sound coloration. Although it is highly efficient, some people think that the bass quality is even worse than that of the bass reflex box.

8. Band Pass is a box design that has only become popular in recent years. The most common designs are 4th and 6th order. The sound quality of this type of box is very poor and is generally not used for hifi purposes! However, since it can enhance low frequencies and has a built-in low-pass filter effect, it is very suitable for AV subwoofer design.