A subwoofer is one of the most important components of a multi-channel speaker system. The organization of home theaters is rarely complete without it. The classic concept of this element of acoustics provides for more detailed elaboration of low frequencies compared to full-size stereo systems. In addition, in some complexes such settings muffle the distorting factors of the sound, making the playback cleaner. More importantly, a home active subwoofer has minimal impact on the physical organization of the system.
As a rule, this is a compact installation, the placement of which also does not matter from the point of view of the listener's sound perception. This is due precisely to the specific propagation of a signal from the low spectrum, which is equally captured regardless of the position of the source. Nevertheless, connecting and configuring the equipment still requires knowledge of some technical and operational nuances of the subwoofer.
What is special about an active subwoofer?
The main difference between active subwoofers and passive equipment is the presence of an integrated power amplifier. It is thanks to this addition that the equipment effectively removes the low-frequency load from the base amplifier. In addition, the device also has an active crossover, allowing you to filter high frequencies and simplify the coordination of equipment with wideband acoustics. Additional features are also available in some models. Thus, a home subwoofer, the price of which is more than 30-35 thousand rubles, is usually equipped with functions for adjusting to special operating conditions. These are not premium models, but a fairly strong middle class. Representatives of this segment support adjusting the frequency spectrum, phase rotation, adjusting the positions of crossover points, etc.
What is a subwoofer
Subwoofer (subwoofer, English) - this word refers to a separately allocated speaker for reproducing low frequencies. After all, without them the sound becomes completely “poor”. This speaker is also called “subwoofer”, but this word is difficult to pronounce. Therefore, the name “subwoofer” stuck.
There are:
Active subwoofer - structurally contains a built-in power amplifier. It has the ability to finely tune the sound wave (in amplitude or phase), and also performs the function of cutting off high-frequency vibrations. Connects directly between the speaker system and the sound source.
The subwoofer is passive - it works in the absence of a power amplifier. Therefore, it must be connected in parallel to stereo speakers or to one of the amplifier channels. If it is connected through a pass-through connection, it will have a negative impact on the sound quality. This manifests itself in a decrease in volume and dynamics. A passive sub does not have any means of adjusting the sound.
How to connect an active subwoofer through an amplifier?
The amplifier is most often equipped with a special RCA channel designed for connecting active subwoofers. Some models even provide several inputs, which expands the acoustic capabilities of the equipment. The user only needs to prepare an RCA cable of the optimal length and connect it to the appropriate connector. As for the simultaneous use of two inputs, powerful home subwoofers connected via a splitter cable help implement this scheme. With this method of interaction, the subwoofer will double the input sensitivity, but this solution will not have a noticeable effect on the surround sound.
It is also worth keeping in mind that subwoofers are usually equipped with right and left high-level channels. In the case of such acoustics, it is especially important not to make a mistake in choosing a cable. It is advisable to give preference to solid copper wire, which will preserve the maximum signal volume. However, if you are using a home active subwoofer from the budget category, then there will be little point in increasing the performance of the connected equipment.
Series, parallel and mixed speaker connection
From the HighPass output, the signal from the subwoofer is sent to the satellites, from Full Range - to another subwoofer if you have four subwoofers and two satellites. Thanks to its design, it is a very reliable connector.
These features echo the well-known concepts of serial and parallel connection of speakers.
You need to place the end of the power wire in the selected location and lay it under the hood of the car. The instructions should also be useful. When connecting speakers, do not forget about their in-phase connection. Known for its high reliability. However, in practice, this is especially true for car audio; other more exotic scenarios are more common, for example, a subwoofer with two coils, or a powerful amplifier and two not very powerful subwoofers. Now let's take an example of the correct connection of the same speakers.
Before connecting the wire, it is worth sanding the selected area. For better fixation, a special podium is installed in the door. By the way, such a closed contour can be created with your own hands.
Connecting cables to the speaker system
Most modern stereo amplifiers have Stereo, Parallel, and Bridge routing modes. With a passive subwoofer the situation is somewhat more complicated. What will we get as a result? Although line signal levels are standardized, inconsistencies between devices can still occur. It is clear that 2 out of 3 speakers will be overloaded - those whose rated power is 1 W.
The receiver has many connectors on its body and requires parallel connection of speakers and a subwoofer. Speaker cables with terminals at the ends - plus and minus, which are either snapped or screwed to the corresponding inputs. Cables with terminals. Series connection of speakers.
Everyone probably understands that although the cable resistance is low, it is there, which means it still causes a voltage drop. To begin with, the simplest option. The first number 3 is the rated power, 3 W. Inspect the conductors at the ends of the cable. Some machines already have holes with rubber or plastic inserts that are designed specifically for wiring the speaker system. How to connect a radio, power and speaker cables, twisted cable connection
Connection to output terminals
Another connection option involves using the main output terminals. In this case, the speaker systems are connected to high-level outputs on the subwoofer. High-pass filters are also located in front of the terminals, providing an average of 6 dB. This configuration ensures minimal pressure on the acoustics in the low-frequency range. But when deciding how to connect an active subwoofer through the input terminals, it is important to take into account the disadvantage of such a circuit. If you choose the described connection model through direct output terminals and filters of the subwoofer itself, then you can achieve optimal sound quality over the entire range while minimizing acoustic palette errors in the low frequency spectrum. But since the connection channels will operate in parallel, the overall load on the system will be significantly increased.
Connection and setup
1. Connecting a subwoofer via a high-level input
I use an integrated amplifier that does not have a dedicated subwoofer output. So in my case the connection will be made through the high-level subwoofer input. To do this, a copper cable with a cross-section of 4 sq. mm was found in the bins.
I connected one of its ends to the amplifier, taking “-” from the left channel and “+” from the right. On the subwoofer, the connection was made in a similar way: on the top pair of terminals I used the black terminal of the left channel and the red terminal of the right channel.
The power cable is connected to the network, the power switch is set to the “Auto” position. At the end of these simple manipulations, the sub turned on and started playing when it received a signal from the integrated unit.
2. Finding a place for a subwoofer
The location for installing the subwoofer was determined intuitively even before I got the sub. No matter how strange it may sound, my choice fully met my expectations. Now I’ll explain what’s going on.
Apparently, due to the specifics of my listening room, after a certain volume level, the imaginary stage began to shift to the left of the center point. The most terrible thoughts came to mind - for example, a driver malfunction on the left column. But such thoughts dispelled quickly and easily: having swapped the shelves, I heard the same effect - the stage was “moving away”. When the amplifier channels were castled, the effect was also preserved.
Apparently, the empty corner in the upper left corner of the room (see diagram below) made its own adjustments to the sound after a certain volume level. The plan was to regulate this resonance in the left corner by placing the subwoofer closer to the right speaker. And the plan worked! After a few minutes of exercise with a 20 kg box, the optimal location was determined.
The subwoofer is located to the right of the center of the room, along the AC line. Its speaker is aimed at the sofa. I didn’t like the option when the sub is even closer to the right speaker. Still, despite the prevailing opinion that low-frequency radiation up to certain frequencies is not localized in space, my hearing identifies the sub as the source of sound.
And the overall sound picture looks more harmonious when the subwoofer is located closer to the center, along the speaker line. Thus, I, as they say, “killed two birds with one stone”, satisfying both my desires with this arrangement of the sub.
3. Phase search
The next stage is phase adjustment. Before starting this task, I turned the subwoofer volume control to its maximum position so that the bass could be heard "in all its glory." At 180, the low frequencies filled the room completely, causing some of the furniture to shake with delight.
In the “0” position, bass degradation was audible to the naked ear. The sub, due to its much greater low-frequency output compared to the bookshelf speakers, was not only able to suppress their bass, but also break out of their captivity. The result of this setting is sad - the sound is like “from a barrel”. In addition, mid and high frequencies come to the fore. In general, this setting is quite easy to decide on, even without any experience.
In addition, for experimental purposes, different phase positions within the range “0–180” were tested. Such an experiment did not bring useful results: as the regulator moved towards the “0” position, the bass weakened, as it gradually shifted out of phase with the acoustics.
Thus, the next subwoofer setup was successful.
4. Working with crossover
It's time to decide on an equally important parameter - setting the cutoff frequency on the subwoofer crossover.
The manufacturer claims that my bookshelf speakers play from 47 Hz to 54 kHz with ±6 dB unevenness. The bass reflex is set to 55 Hz. Based on the results of the adventures with the tone generator, the information about the low-frequency range is quite reliable, and it can be used in further settings of the subwoofer.
But it’s worth considering one more point: the resonance of the room, to my ears, coincides with the bass reflex setting. At about 55 Hz there is a rather unpleasant hum in the listening room. The situation is smoothed out by the fact that this resonance makes itself felt only at a fairly high volume, which is higher than what I use for long-term listening.
So the first crossover setting that came to my mind was the leftmost setting of the control - 40 Hz. A few short listens at half the subwoofer volume and I liked the result. Then, smoothly turning the crossover clockwise, I conducted the same short listening sessions. But eventually I returned to the original setting.
When the crossover cutoff was shifted towards an increase in frequency, a clear excess of bass was felt in the range where the bass reflex of speaker systems works. The filter in the extreme right position, to my ear, adds a boominess to the overall low-frequency picture. So based on the above, the decision was made to leave the filter setting at 40Hz.
5. Adjusting the volume of the subwoofer relative to the stereo pair
I read somewhere that in recording studios it is customary to match the subwoofer and acoustics using a tone generator at a frequency of either 80 or 85 Hz. Why not try it?
Running the tone generator first at 80, then 85 Hz, using improvised tools, I tracked the peak values on the bookshelf speakers, and then on the subwoofer. The peak value of the subwoofer turned out to be lower, so the volume knob had to be turned up from 12 o'clock to about two o'clock.
A quick listen gave a negative result: to my ears, the bass turned out to be too accentuated. By fine-tuning in the opposite direction, I found the optimal position of the regulator for me - a little more than half.
So, what do we have as a result of the settings:
• the sub is connected at a high level to the amplifier terminals;
• placement - to the right of the center, along the AC axis;
• phase regulator in position “180”;
• crossover cutoff is the minimum possible - 40 Hz;
• volume control at just over 12 o'clock.
Setting up a home subwoofer by frequency
Basic setup of the equipment is carried out taking into account the characteristics of the main acoustics. In any case, it’s worth focusing on the main parameters. The setting itself can be adjusted in the parameters of the audio crossover and phase switch, which will be discussed below. But before it is possible to begin direct calibration of acoustic indicators, you should check the quality of the connection and, if possible, optimize the connection nodes. Moreover, modern subwoofers for home theaters in certain lines are equipped with wireless communication modules. This means that such equipment does not require the use of traditional physical cables at all and is connected through radio communication sensors. That is, you only need to synchronize the equipment via a Bluetooth module or other wireless communication system.
Problems with sub
The undoubted advantage of a subwoofer is that it does not need to be placed strictly at a certain point, like speakers. Theoretically, it can be stuck anywhere, and it will be heard equally from everywhere. In practice, it is with it that most often problems arise: if you put it in a corner, it mumbles and hums, and the walls are shaking; if you put it in the center, the bass disappears altogether. If you place the sub on a shelf, in a closet, in a mezzanine, under a table or sofa, there will be more bass, but it will become more buzzy and muddy.
Much depends on the room: its size, shape and even the amount of furniture. Sound waves are an actual physical object that interacts with the surrounding space, and low frequencies carry the most energy. If the room is small, then it is difficult for energy to dissipate in a confined space. As a result, standing waves are formed. They are called room mods, and there are calculators that allow you to calculate them based on the dimensions of the room.
In a large room, modes can be below 20 Hz, these will not interfere. But the smaller the room, the higher the frequencies at which standing waves are formed. Moreover, if there is a problem at 50 Hz, then it will also be at multiples of 100 Hz and 200 Hz.
To detect modes yourself, just turn on a few test signals at bass frequencies and walk around the room. In some places (for example, in the corners) there will be a lot of bass, and in others (usually in the center) there seems to be no bass at all. This is understandable - some of the waves combine with waves from the subwoofer, reinforcing each other, while the other part enters into antiphase with the source and forms voids. It makes sense to remember these points, not to put a sub there and not to make a listening point.
The second point is that the subwoofer vibrates noticeably during operation, and if you place it directly on the floor, and closer to the wall, then the entire entrance will vibrate. Likewise with a table or cabinet: sound travels much better and faster through solid matter than through air, so wooden furniture will only increase vibration and vibration. Many subs are already equipped with rubber feet, but if you additionally place it on a vibration-isolating stand, it will absorb most of the vibrations. These are sold ready-made, but you can make them yourself from thick foam rubber.
Crossover adjustment
The crossover setting is designed to set the frequency spectrum of the woofer separation. That is, with the help of this regulator, subwoofers for home theaters are precisely adjusted over the entire range of signal reproduction. Some models even provide for extreme frequencies at which the equipment is not perceived at all by the human ear. The standard value will be the average position of 80 Hz. You should deviate from this value in cases where there is a booming bass sound. In such a situation, it is recommended to move the regulator towards a lower frequency.
Should I choose 5.1 or 7.1?
This question is becoming less and less relevant, and with the advent of Blu-ray and HD DVD “in every home” it will completely lose relevance: for new formats 7.1 is the de facto standard. However, in some cases 5.1 is preferable. For example, in small rooms in which the rear speakers installed at an angle of 110 degrees will be located further from the viewers’ ears than the side and rear speakers in a 7.1 scheme. This means that the surround sound will be more voluminous due to better sound dispersion, despite the smaller number of channels in the system.
Source
Setting the phase switch
The phase switch, in turn, is designed to compensate for the difference in the gaps between the main subwoofer installation and its components. This control also helps to coordinate signals from different satellites. It is recommended to configure a home active subwoofer using this parameter while playing music excerpts with a man’s low voice. The user must determine during the listening process in which phase switching mode the vocals sound most natural and spacious.
Additional components to add after the subwoofer
After adding a subwoofer, you may be wondering what you could add next to make your sound even better. In addition to your soundbar's built-in speakers, which are your front speakers and subwoofer, you may want to consider rear speakers if your soundbar is compatible.
Rear speakers upgrade your audio system from a 2.1 or 3.1 system to a 5.1 system, which helps achieve surround sound. With a 3.1 system you do get great sound, but there's no denying that it's heavy. In a 3.1 system, your rear speakers will help fill the room with sound and make it even more enjoyable.
Check out our blog post detailing all the surround channels to learn more!
Recording source: https://thehometheaterdiy.com
Eliminating acoustic distortion from a subwoofer
For a number of reasons, even expensive branded subwoofers do not always provide crystal clear sound in the low range. However, in some cases such problems can be corrected. For example, pronounced acoustic hum may be caused by dispersion in the subwoofer wires. This is exactly the case when the quality of the cable plays a significant role in the characteristics of the sound transmission. This problem can be corrected either by updating the wire, or by manipulating the volume control in order to find the optimal clean sound. In particular, it is recommended to initially connect powerful home subwoofers via a thick, high-quality RCA cable with an effective shielding function. Often, subwoofer users also note a loud hum, which by all indications is provoked by third-party factors. The so-called current filter in the cable will help eliminate such flaws.
Can I put a subwoofer in a closet?
Since subwoofers often sound best at the front of the room, you may be wondering if they can be placed inside a cabinet or placed on a shelf in your entertainment center. This is a common question because often you don't need to be looking at the subwoofer all the time. Unfortunately, placing a subwoofer in a closet is a bad idea unless there is some highly breathable material in front of the subwoofer firing point.
Subwoofers should not be placed in cabinets because they sound bad. You prevent sound from spreading throughout the room. The sound will get stuck in the cabinet or cabinet and may even add unnecessary vibrations and noise due to its power.
Additionally, as a general rule, equipment should not be placed in small, confined spaces, as this can lead to overheating and malfunction. To ensure the longevity of your subwoofer and sound system components, store them in an area where they can breathe and function properly.
How to choose the best subwoofer?
A high-quality system may well have average performance characteristics and, subject to proper connection, produce a decent acoustic palette. Thus, a powerful home subwoofer, the price of which is about 50-60 thousand rubles, is more likely to cope with its tasks of processing the low frequency range within the limits allowed by the main acoustics. However, the same effect will be provided by an economy class model, which in its maximum performance parameters corresponds to the capabilities of the head unit. That is, overpaying for equipment is not always justified, as is the case with satellites.
In addition to the basic characteristics of impedance, power and frequency range, you should also pay attention to the material of manufacture. Despite the popularity of plastic, the demand for a wooden active subwoofer continues. Reviews note that a body made of natural material is most advantageously involved in suppressing vibrations and uniformly dissipating the operating signal. True, wood is inferior to plastic in terms of practicality from an installation point of view.
Classification of subwoofers and methods of installing them in a car
Connecting an active subwoofer One of the common ways to connect an active subwoofer is the following sequence of actions: Power and signal wires are used to install the subwoofer. At the end of this article you will find a diagram for connecting the subwoofer to the standard radio and amplifier, as well as video instructions on how to properly install and connect the subwoofer in the car yourself.
However, such devices are not very powerful. Connection diagram for a passive subwoofer in a car Connecting a passive subwoofer in a car is somewhat more complicated, since it needs to be connected not directly to the radio, but through an amplifier, see the connection diagram above. We lay the wiring in the engine compartment in the standard wiring harness and bring it out into the cabin. The amplifier is used to increase the volume headroom, reduce distortion and improve the sound quality of music.
As a result, such a good quality kit turns out to be more expensive than a ready-made active sub. To prevent the cable from fraying, it is better to insert a rubber bushing, for example, a piece of hose. Only high-quality wires are used for installation.
Since the wires will have to be pulled through the interior, in order to avoid chafing of the cable, it is better to use corrugated sleeves, which must be securely fastened to the cable connection points. To connect a passive crossover, it is placed directly in front of the load, i.e. Crossovers are of active and passive types, as well as one- and two-way.
Classification of subwoofers and methods of installing them in a car
Using a converter involves connecting the main speakers through an amplifier. Let us also add that any work on connecting electrical equipment in a car must be carried out by removing the terminals from the battery.
To which the seller offered me a more budget-friendly option. However, it also happens that an amplifier or active subwoofer does not have such an input.
The wires should not be thin. The subwoofer's subwoofer bass and front bass are enhanced or sounded quieter by different sized speakers. Subwoofer lighting It is better to do the lighting for the subwoofer speaker at the stage of manufacturing the box. How to connect a subwoofer and amplifier. Fast and clear.
