Comparison JBL Stage 810 vs ACV BTA-8

— In the body. Subwoofers consisting of a full-fledged enclosure in which the speaker (speakers) is installed. Usually they are designed to be installed in the boot. Cabinet models are easy to install, but take up a significant amount of space, and in most cases have some phase delay that requires phase adjustment (see below) to synchronize with the front speakers.

— Without body. This category includes subwoofers designed to work in their own cabinet, but not equipped with it (not to be confused with Free Air — see below). Thus, having bought such a speaker, you can choose a case for it at your discretion — or even make it yourself. This, of course, is more difficult than immediately acquiring a cabinet “subwoofer”, however, it gives more opportunities for adjusting the acoustics to personal preferences. Other advantages and disadvantages of frameless models are similar to case models.

— Without body (Free Air). Car subwoofers of this type are not only not equipped with a case, but they do not imply its use at all: usually Free Air models are designed for installation in the rear shelf or back of the rear seat, and the boot plays the role of the case. The advantages of such an installation are the minimum space occupied (which is important with small boot volumes), as well as the almost complete absence of delay and the ease of “docking” with the main c...hannels of the audio system. On the other hand, installing a Free Air subwoofer in itself is associated with a number of difficulties. For example, for the effective operation of such a speaker, the boot must be hermetically separated from the passenger compartment; it is quite difficult to provide such conditions, and in some body types (for example, station wagons) it is almost impossible. In addition, such a speaker has much less ability to adjust to a specific interior than a cabinet one; and with a tightly loaded boot, the sound characteristics deteriorate noticeably. Therefore, paying attention to such “subs” is primarily for owners of sedans who do not have to carry a lot of luggage.

— Closed box. The simplest type of case: a box closed on all sides with a speaker (speakers) on the front panel. The advantages of such models are high accuracy of sound transmission and low cost, the disadvantages are low sensitivity and somewhat “flat” bass.

— Phase inverter. A classic phase inverter is a hollow tube connecting the internal volume of the case with the outside world (however, there are other options for such a connection). The length of the phase inverter channel is chosen so that the sound waves of a certain range, passing through it, are inverted in phase relative to the waves from the speaker (hence the name). This improves (in particular, "deepens") the sound of the subwoofer and allows you to achieve good performance with a small cabinet size. On the other hand, the sound stream in the tube creates a certain additional noise.

— Strip. A design that combines the features of a closed box and a bass-reflex enclosure. One of its parts is made closed, and the second is equipped with a phase inverter tube; between them is a partition, on which the main speaker is located. Unlike previous types, the speaker is entirely inside the case. Strip-line enclosures provide louder sound than boxes or bass reflexes, with sound quality comparable to the latter. The disadvantage is the complexity of the design, as a result — a slightly higher price.

— Case Box. Literally "box". The simplest type of case, in fact, is a box of medium dimensions, designed for installation in the boot.

— Compact. This option means rather than the shape, but the size of the case — as the name implies, it includes devices that have small dimensions. Such subwoofers are as simple as possible to install, some models can be installed directly under the seat. At the same time, their sound quality and power are usually lower than those of full-size ones.

— Tube. The case is in the form of a pipe, on one of the ends of which a speaker is displayed. This form does not significantly affect the sound characteristics, it plays mainly an aesthetic role — subwoofers-pipes look quite stylish.

— Active. Subwoofer equipped with its own built-in amplifier. Such a subwoofer can be connected directly to the signal source, without any additional amplifiers; while the built-in amplifier, by definition, has characteristics that best match the parameters of the speaker. And when using other amplifiers, an active subwoofer reduces the load on them, which has a positive effect on sound quality and power. In addition, your own amplifier can be equipped with its own sound tuning tools and other additional features. On the other hand, all this affects the cost of the device, and active models are somewhat more difficult to install, because. require separate power supply.

— Passive. Subwoofers not equipped with their own amplifier. They are cheaper than active ones and easier to install. work without a separate power supply, however, the connection is fraught with some difficulties: for normal operation, an amplifier is needed, the characteristics of which (in particular power and impedance, see below) must optimally match the parameters of the subwoofer.

The average (root mean square — RMS) power of the input signal, at which the subwoofer is able to work continuously without negative consequences (damage, failure) for at least an hour. The rated power of the subwoofer must be greater than the power of the amplifier connected to it — in order to avoid overloads.

The maximum signal power that the subwoofer is able to withstand for a short time (up to several seconds) without any negative consequences. When selecting an amplifier-subwoofer pair, it is recommended to take a subwoofer with a maximum power of at least twice the maximum power of the amplifier. In general, the higher the maximum power, the more resistant the subwoofer is to overloads.

The range of audio frequencies reproduced by the subwoofer. It is believed that the human ear is capable of perceiving a frequency range of the order of 16 – 20,000 Hz, but in this case note that the subwoofer is designed to reproduce the lower frequency band (up to 200 Hz). Accordingly, in the case of the lower limit of the range, everything is simple: “the lower, the better”; the upper one should not be lower than the lower limit of the main car audio — otherwise there will be "gaps" in the frequencies, which will affect the sound quality.

Sensitivity determines the loudness of the subwoofer when a signal of a certain power is connected to it: with equal signal power and impedance (see below), the subwoofer with the higher sensitivity will sound louder.

A dual voice coil is actually two separate voice coils on the same speaker. This allows you to connect two amplifiers to the subwoofer at once, thus providing high sound power.