Comparison REL T/5i vs REL Acoustics T 7

— Closed type. The simplest type of construction: a closed (sometimes hermetically sealed) case with a speaker placed on the front panel. It is believed that such subwoofers have low sensitivity, which, however, is offset by high sound transmission accuracy and low distortion.

— Phase inverter type. In the cases of such subwoofers, a tube is installed that has an outlet to the surrounding space. The length of the tube is chosen so that a signal comes out of it, inverted in phase relative to the signal from the front of the cone (in other words, from the main speaker). This improves the sound of the subwoofer and enhances the sound pressure. The disadvantage of a phase inverter is the additional noise from the sound stream in the tube.

— With a passive radiator. A design similar to a phase inverter (see above) in terms of purpose and principle of operation, however, instead of a tube, such subwoofers use the so-called passive emitter. In fact, it is an ordinary speaker, devoid of a coil and a magnet and playing the same role as the phase inverter tube. The use of a passive radiator allows you to get rid of the noise of the air flow, characteristic of phase inverters.

Rated power of the subwoofer. Technically, this is the highest average (rms) sound power at which the device can work normally (without sound distortion and damage to components) for an unlimited time. Simply put, the more powerful the subwoofer, the louder it is. The choice for this parameter depends primarily on the size of the space / room that is planned to be covered; detailed recommendations for different situations can be found in special sources.

Also, the power is directly related to the characteristics of the amplifier used with the subwoofer. For active subwoofers (see "Type"), this item actually indicates the nominal power of the built-in amplifier; the speaker itself can be more powerful, but it doesn't matter anymore. For passive models, the power rating corresponds to the highest amplifier power that can be connected to the speaker without the risk of damaging it at high volume.

The sensitivity value determines the volume of the subwoofer when an external signal of a certain power is connected to it. The higher the sensitivity, the louder the sound will be, with equal signal power and impedance.

The range of audio frequencies reproduced by the subwoofer. As a general rule, the wider the frequency range, the richer the sound and the more detail the speaker can convey. However, it is worth remembering that subwoofers as a class are designed for low and ultra-low frequencies in the range from 20 to 150 (sometimes 200) Hz. Therefore, in fact, a significant difference in sound is noticeable only with a large difference in the reproducible ranges (for example, 20-200 Hz and 50-150 Hz).

Also, do not forget that an extensive frequency range is not yet a guarantee of high-quality sound; and in some cases (for example, if the main speakers of the speaker also cope well with low frequencies), it may be completely redundant.

The presence of a wireless connection in a subwoofer is most often Bluetooth: this standard is practically generally accepted in modern electronics, it is supported by the vast majority of smartphones, tablets and laptops. Note that we can talk about connecting an audio signal, as well as connecting to a device like a smartphone or tablet to manage settings. However, the latter option is not common — mainly in concert models, based on the ability to reconfigure the subwoofer even in a situation where there is no direct access to it.

If we talk about wireless sound transmission, then this option is convenient primarily from the point of view of choosing the optimal installation location: moving the subwoofer around the room, you do not need to mess with wires, and the Bluetooth range reaches 10 m. However, the quality of sound transmission with a wireless connection may be lower than with wired, but for bass this point is not as noticeable as for other frequency bands.

Cutoff frequency of the crossover installed in the subwoofer (or supplied with it — for passive models, see "Type").

The crossover splits the audio signal into separate frequencies so that only the bass goes to the subwoofer and only the main range goes to the speakers. Such a device is mainly equipped with home models (see above). And the crossover frequency is the upper threshold of the frequencies fed to the subwoofer. This information is important for matching with the rest of the speakers: ideally, the lower threshold of the main acoustics should correspond to the upper threshold of the subwoofer, otherwise the frequencies will either overlap or dip in them (neither of which contributes to sound quality). For the convenience of matching, the crossover can be made adjustable (see above).

- MDF. Medium-density fiberboard is one of the most popular materials for modern speaker cabinets, including subwoofers. This is due, on the one hand, to the relatively low cost and neat appearance, and on the other hand, to excellent acoustic characteristics. MDF cases are found in “subs” for all purposes and price categories.

- Tree. Natural wood is well suited for low-frequency acoustic enclosures; its performance characteristics are comparable to MDF described above. At the same time, this material is considered more “natural” and has its own beautiful surface pattern, but is noticeably more expensive. Therefore, although wooden cases are common, they are not as widespread as MDF.

- Plastic. The main advantage of plastic is its low cost, but it is very difficult to create a body with the necessary acoustic characteristics from this material. Therefore, plastic subwoofers are extremely rare, mostly built-in models.

- Metal. In this case, we mean various alloys and aluminium models. The metal is highly durable, but the acoustic characteristics are far from optimal. This requires the use of various tricks, which respectively affect the price of a metal subwoofer. Therefore, this option is quite rare.