Various Subwoofer Box Enclosure Design

Performance subwoofer to produce low bass sound & also solid, of course supported by a subwoofer enclosure or box. Box subwoofer in a car or a home theater typically has a different size, it is adjusted to the recommendations of the technical data from these subwoofers. However, each audio installer, have different styles in a box design. Box consists of various types and models. Design, size (dimensions) and a subwoofer box models are usually clearly taken into account at the time of manufacture, even carefully designed too often acted the Installer. Clearly, each type of box has a value of strengths and weaknesses, all models of boxes, if applied correctly, it will give the performance of the subwoofer becomes very maximum. subwoofer box type the following are frequent and generally we meet in the application of audio equipment. types are:

1. Sealed Enclosures

This model has a box room that is not perforated. Sealed box shape is believed to provide a smooth bass thump and appropriate response. Well make audio lovers cosmetics typically use this box type the following with subwoofer installation reverse (inverted).
Pros: Small Box, capable of great exertion, the right response, easy to make, to avoid errors in the making.
Disadvantages are less efficiency (requires more amplifier power) than vented enclosures and less low bass as compared to a properly tuned vented enclosures ABOVE the port tuning frequency.

2. Vented Enclosures

Vented enclosures are similar to a sealed enclosure in design except that they add a “port” that is a certain length and a certain area around. This port, usually a length of PVC pipe, is tuned to a certain frequency by variation in the two port parameters of area and length. By adding this port, the rear wave of the cone motion is used to reinforce the front wave. When done properly the subwoofer system becomes more efficient than a comparable sealed enclosure above the port’s tuning frequency. However, below the port tuning frequency the woofer will become unstable and “unload” causing the woofer to oscillate violently, leading to premature woofer failure when driven with excessive power.
Advantages of this design are increased efficiency and a lower frequency extension above the port tuning frequency.
Disadvantages are a more complex design, a larger enclosure as compared to a sealed design, lower power handling, and slightly less transient accuracy.

3. Infinite Baffle “Enclosure”

Subwoofer attached to the surface by separating the wave front with the rear, this form does not require a large size. Box model is usually often used on vehicle type sedan.
Pros: Resonance is very low, the use of a place not too big.
Disadvantages: The output is limited, it is usually very difficult to reinforce the front wave from the rear.

4. Reflex bandpass

The purpose of the band pass system is increased efficiency over a small range of frequencies. This design also helps filter out unwanted midbass and upper frequencies.
Advantages of this design are a high efficiency over a small range of frequencies and some filtering characteristics. Advantages of this design are a high efficiency over a small range of frequencies and some filtering characteristics. Disadvantages are decreased frequency response, less accurate reproduction, extreme complexity in design and assembly, larger enclosure size, greater woofer unloading and decreased power handling.

5. Isobaric loading

Isobaric is not actually an enclosure type but a woofer loading method. Isobaric loading can be used in conjunction with any of the enclosure types, except perhaps infinite baffle. Isobaric loading consists of two woofers coupled together by a short enclosure which is only long enough to prevent the two woofers from striking one another. The woofers may be mounted face to face, back to back or front to back. However it is important to have the woofers firing in phase with one another. In order to accomplish this with the woofers firing front to front or back to back one of the woofers speaker leads must be reversed with respect to the other woofer. Isobaric loading is usually used when space is at a premium or a maximum number of woofers wish to be used in a certain volume of space. By isobarically loading the woofers, a box of only half the size of a one woofer box is needed. For example, if a 12″ woofer requires a two cubic foot box, the same 12″ woofer isobarically loaded only requires a one cubic foot box. The cost of this design, other than doubling the woofer cost, is a reduction in the subwoofer system efficiency by three decibels (if both woofers are given the same power as a single woofer), which is equivalent to halving the amplifier power. New, small box subwoofer designs have all but eliminated the need for isobaric loading in car audio and it has fallen out of popularity.
Advantages of this design are increased linearity in the speaker movement, lower space requirements, and increased power handling. Disadvantages are increased cost, increased design and assembly complexity, and decreased efficiency.