How to choose a car subwoofer?

It is worth starting with a small axiom: it is practically impossible to assemble a really high-quality audio system without buying an autosabwoofer. The smallest subwoofers start with a six-inch size. This dimension is more common in broadband door speakers, less common in the narrowband frequency range. The subwoofer "sixes" are distinguished by an increased diffuser stroke (to reproduce lower frequencies) and an improved ventilation (cooling) system of the sound coil. The ability to "live" in a small-sized case is the main advantage of kids, since a lighter diffuser is more easily controlled by an amplifier. This means that the mini-subwoofers sound a little faster, sharper and clearer than their bulky brothers in frequency.

The larger the speaker, the higher the volume and the more saturated the bass will be, but at the same time, the "small" models sound faster and clearer

But at the same time, a small area of the diffuser creates less sound pressure, so not loud enough subwoofer kids are most often put in pairs: two 6-inch models will be slightly louder than one 8-inch "sound pump", two 8-inch ones are better than one dozen, etc.

Most of the subwoofers on the market are offered in 10- and 12-inch sizes. This is the golden mean between the not-too-bulky case, the optimal sound pressure level and pulse characteristics, i.e., the accuracy and speed of the bass.

15- and 18-inch subwoofers are the loudest and require about 50-100 liters of acoustic design. In other words, you will have to sacrifice a place in the boot for them.

Type of subwoofers

The amplifier built into the radio is designed for voicing four coaxial or component speakers. But if the device has the ability to adjust the volume of the subwoofer, then it also has line outputs to an additional external power amplifier for the subwoofer.

An additional amplifier can be either built into the subwoofer housing or sold separately. The main thing is that it must be mandatory, otherwise we simply won't hear the subwoofer.

Active subs have power, linear and high-voltage inputs (from above). Sometimes the connection is made in the form of a common opening (photo below)

An active subwoofer is a low–frequency speaker in an acoustic design (housing) equipped with its own power amplifier. Choosing this type of subwoofer, the user does not have to have additional knowledge on the connection of power, resistance and connection options – everything has already been selected, connected and packed by the manufacturer for you. It is easier to install it, because there is one box, not two. We just measure it in our boot and, having installed it, enjoy the deep bass.

You can distinguish an active subwoofer from a passive one by the number of connected wires. Instead of two acoustic terminals, active subwoofers have power, linear and high-voltage inputs (for connection to standard radio recorders that do not have RCA line outputs). I.e., quick disassembly (for example, for transporting something in the boot of a car) and reverse installation of the active sub becomes more complicated. It is convenient if the connection is made in the form of a common connector, suggesting the option of easy disassembly of the subwoofer without the hood fuse.

The smallest and flat subwoofers also belong to the active ones, which, due to their size, claim to be hidden under the seats. Such a solution, which saves space in the boot, will be positively appreciated by any motorist, but most likely only until you turn on the subwoofer itself. Unfortunately, flat active subs are a compromise solution between standard acoustics and any, even the smallest sub in a traditionally large box. Only more expensive models are able to refute
the nickname "vibrators" stuck to them.

Active subwoofers can be in any acoustic design, except for free-form (bodyless), but they are most often found in closed and phase-inverted enclosures. They consist mainly of a more low-cost set: amplifier + woofer head + housing + wiring. Firstly, so that the "equal" (i.e. the result) does not go off scale, and secondly, a more advanced buyer prefers to assemble his audio system separately.

A passive subwoofer is a low-frequency speaker in a case without an amplifier. That is, it is an unfinished product that needs to be supplemented with an amplifier, without which, in fact, it will not "sing". This type of subwoofers is offered on the market in much larger variations of acoustic design, which we will now consider in more detail.

Design of subwoofers

A closed case is the simplest design option

The volume of air in the housing directly affects the parameters of the speaker. Different types of acoustic design are used to adjust the range of reproducible frequencies and increase the sound pressure at certain frequencies.

A closed enclosure is the simplest acoustic design option and, usually, the smallest in size. The air inside such a sealed box is locked and has no way out, and therefore it is not the loudest. But the subwoofer sounds classically smooth and clear in a closed case, but if you do not have enough pressure with an emphasis on certain frequencies, then it is better to choose a different acoustic design.

The phase inverter housing has a special tube, which provides bonus decibels

Phase-invertor housing. This type of subwoofer has a special tube (phase inverter) connecting its internal space with the outside world. Here, the radiation from the rear of the diffuser does not die in a sealed design, as in the case of a closed case, but is used in the form of bonus decibels. Only a certain number of "fleshy" (or they are also called "tasty") frequencies "crawl" through the pipe or slot, which, when combined with the frequencies emitted by the front part of the diffuser, double and amplify, as if the second speaker plays along through the phase inverter port, but in a very narrow range.

The phase inverter resembles the "basbust" function on power amplifiers, only the "phasers" accentuation of the "tasty" frequency turns out to be more natural and cleaner. In order not to lose extra decibels, it should be taken into account that the port inverting the rear phase cannot be blocked with anything.

The passive emitter works with the effect of a phase-invertor housing, embellishing a certain frequency

The dimensions of the phase invertor housings, usually, are always larger than closed ones. And there is a plus in this: the larger the acoustic design, the louder the trumpet "phasica" plays along. The closer the phase inverter is to the volumes of the closed case, the less noticeable the work of the "phaser". But you can't get too carried away with this effect, because too much volume is blowing, and not playing. This is clearly noticeable on cheap models in the form of a barrel body, which are focused on attracting an inexperienced buyer with a loud and mumbling bass.

The passive radiator works with the effect of a phase inverter housing, embellishing a certain frequency. Only in this design, the second diffuser acts as a "basbust". From the front it looks like a regular speaker, and from the back it is devoid of a sound coil and a magnetic system. The main speaker makes the naked movement play along at its resonant frequency.

The band case is a solution for gourmets of powerful bass

Bandpass or bandpass is a solution for gourmets of powerful bass. Such devices are rarely on the market because of their considerable size. The woofer head in this form of execution is ideally protected from external damage, because it is located between two types of housings: closed and phase-inverted, i.e. two housings in one. It is absolutely impossible to close the port here, this is the only output of amplified and low frequencies. This kind of sound performance is better suited for musical genres that require as much sound pressure as possible, rather than transmitting all the subtleties of sound.

Bodyless subwoofers can be of two types:

Bodyless subwoofers come in two types: some can play without a case at all, others are simply sold separately from it

Free air is a low–frequency player capable of playing without acoustic design. It is installed in the rear shelf if it is smooth and rigid, which is very rare in modern cars, or in the opening rear armrest, where you first need to make a podium.

The woofer head, which is sold without the necessary housing for it. This is a subwoofer for the most advanced users. You need to have certain knowledge and skills to make the right case with your own hands. Or you can turn to professionals and order, for example, a Stealth case hiding in the rear wing.

Power

The subwoofer should be the most powerful link in the audio system, because:

• the sensitivity of low frequency heads is generally lower than door coaxals or components;
• he often has to fight his way through the back shelf and the seat to get to the driver;
• the threshold of human audibility of subwoofer frequencies is much lower than the audibility of medium frequencies;
• at speed, it is drowned out by the noise of the engine and body;
• there are not so many music recordings with a proper bass level.

Two power values are indicated on bright packages: peak and nominal. Moreover, the more low-cost-friendly the model, the bolder and larger the font of peak power.

When purchasing a subwoofer with the enticing inscription MAX 1300 W, you need to understand that it does not speak about the power with which you will now have a subwoofer "singing", but about the cotton wool limit for it, which in fact can completely burn the loudspeaker. Much more important is the value of rated power, meaning long-playing power. Usually, it is 3-4 times lower than the peak, which is important for the correct selection of the amplifier.

The range of reproducible frequencies

The useful operating range of subwoofers is from 20 to 120 Hz, although in fact it is still narrower. From above, the subwoofer range when setting up the audio system is connected to the edge of the frequency range of the door midbases or ovals in the rear shelf. For correct docking, a low-pass filter (LPF) is used, which cuts frequencies above 80-100 Hz so that the subwoofer is not localized from the boot, and high and medium frequencies do not overheat the sound coil. From below, the subwoofer range below 30-20 Hz should also be trimmed with a high-pass filter (HPF). For subfoovers, this filter is called a "subsonic". Its task is to protect the mobile speaker system from excessive vibrations at infra-low, inaudible frequencies.

In other words, only a small part of the frequency range specified in the instructions is used, the rest needs to be cut off with filters so that the bass sounds more efficient and better. Some subwoofers, mostly smaller ones, may not play to the edge of the human-audible range of 20 Hz, but this is not so scary, because it is almost impossible to find recordings with this frequency. The frequency range ending at 40-30 Hz is quite enough to play all musical styles.

What else you need to know when choosing a subwoofer:

And finally, one more addition about the influence of the case on the nature of sound transmission. Different acoustic designs are suitable for different musical styles. Bandpasses or phase inverters are more suitable for rappers, and free–range or closed acoustic designs are more suitable for classics. Undecided in their musical preferences, it is recommended to pre-listen to the subwoofer before buying.