Subwoofers are speakers that are specifically designed to handle extremely low frequencies. The first subwoofer amplifier was developed in 1970 by Ken Kreisler. Modern devices practically do not differ from it. They function like typical power amplifiers. The only difference is that they bring more power to the speakers, create a lot of bass movement for high volumes. Building your own subwoofer amplifier is a useful way to save money on audio equipment, so it's best to know how to make your own subwoofer for your home.
Basic system concept
The first thing to understand is the basic concept of a subwoofer. The main idea is to reproduce low frequencies, approximately two octaves from 20 Hz to 80 Hz. From here comes the first prerequisite - the presence of a special cabinet that will generate low frequencies and guarantee good bass.
The second condition is the room's own acoustic properties. If you put the best in the worldsubwoofer in an acoustically bad room - no bass! If acoustic problems are identified in the room, it is important that they are corrected before making a subwoofer with your own hands.
Another useful benefit of a subwoofer is the extra power control it provides to the system as a whole. Acoustic energy in music is highest at low frequencies and decreases as the frequency increases. Thus, the use of a homemade cabinet to work with most dizzying bass is possible only with the use of special audio systems.
Creating a custom subwoofer
Before making a homemade subwoofer, hobbyists ask themselves the question: "One or two subwoofers?"
Most stereo systems have two main speakers, but only one subwoofer. Some units may have two (or more) subwoofers, but one is usually sufficient. The reason for this is because for frequencies below 700 Hz, human hearing measures the phase difference between the sound entering each ear. Sources generating low frequency sounds (below about 100 Hz) tend to do so in an omnidirectional manner, where the sound wave travels from the source in all directions, and the wavelength of the sound is usually longer than the object itself.
Before you make a subwoofer with your own hands in the car, you need to purchase:
- Old computer power supply.
- Car amplifier.
- Speaker terminal.
- Sandpaper, primer and paint.
- Cordsto connect.
First, you need to draw up a diagram of the case, calculate its volume and port size, with the possibility of a useful expansion up to 32 Hz. Before making a home subwoofer with your own hands, choose the design of the box, usually a cubic case with a side of 35 cm is enough.
Device made:
- To make the case, you can use an 18 mm fiberboard panel, after cutting out all the details according to the drawing.
- The port will need to be made after the case is made. Before you make a speaker (subwoofer) with your own hands, you need to decide on the shape of the ports. They can be of different shapes: round, square and rectangular. For this type of device, the use of a 110 mm rectangular chute is sufficient.
- Then you need to glue the body structure with wood glue and leave it on the clamps, preferably overnight.
- Install the port with sealant, glue and silicone.
- Reinforce the free end to prevent vibration.
- Perform body finishing, polishing, priming, painting. Before making a subwoofer with your own hands from ordinary materials, it is best to apply a layer of primer several times, leaving it overnight, then work with fine sandpaper until the finish is smooth to the touch. This will give a nice glossy finish after a few coats of spray paint.
- Internal isolation and noise reduction device. Add silicone wool to the cabinet space and secure it to the walls with siliconepistol. This should make the cabinet less boomy as standing waves and resonance are limited and bass is punchier and deeper.
- Before you make an active subwoofer with your own hands, you need to decide on the built-in power supply.
- Need to connect a 500W PSU from an old PC with all 12V wires and grounding using Lanzar Heritage 2000W Universal Car Amplifier.
- Then connect the green wire on the power supply with the ground wires on the amplifier, and if the amplifier has REM, connect it to 12V. Everything, after that the device should work.
Loudspeaker bass control
Bass management is the process of removing the bass element of the signal fed to each satellite speaker and routing it to one or more subwoofers. It's basically the same as a regular crossover, except that the bass driver is in a separate cabinet and a control is needed to combine low frequency sounds.
Before you make a subwoofer for your computer with your own hands for a simple stereo system, you need to think about the bass management system. It is usually built into the subwoofer and can be active or passive (most systems are active).
There are various connection schemes, but most of the line signals from the controller or preamp go to the subwoofer first, and after the signals are filtered, they go to the speakers. Some systems work the other way around, at firstconnecting the signal to the speakers and then to the subwoofer.
Systems intended for home use often operate with speaker level signals. For surround sound systems, bass management is usually done in the surround controller, not the subwoofer.
Types of woofer enclosures
It's relatively easy to create high levels of low frequencies with the very low bandwidth that most cheap subwoofers have. Before you can make a subwoofer with your own hands, which should generate high performance in a wide bandwidth and low distortion in a reasonable size, you need to study the perception zone well.
Creating low frequency sound at studio playback levels requires a lot of air movement. This requires a powerful amplifier, a very large bass driver (or several smaller ones), and a multi-level diaphragm. An easy way to achieve high efficiency is to place the bass source in a so-called "band cabinet". It is essentially a resonant body and sound through one or more ports.
Most subwoofers use a form of "resonance" that combines practical efficiency with bandwidth in large cabinets. A less common alternative is the "closed box" design. The cabinet is sealed and only the front of the speaker transmits sound into the room. This approach has significant advantages in terms of its phase response, time and distortion. Experts believe that you should not get carried away with the size of the subwoofer, as larger is not necessarily better.
Electrical equalization
For many novice users, this is a very confusing process. To make a mistake in it is to destroy the accuracy of the sound monitoring system as a whole. It is very important before you make a subwoofer with your own hands, to understand the geometry of the movement of sound waves. Therefore, satellite speakers must be placed in phase with each other in electrical polarity and timing. If it is not, the audio graphic area will have a distinct level of bulge or drop.
The subwoofer and satellite speakers have their own mechanical phase responses, as well as the electrical phase characteristics of the crossover filters themselves. There is also a time delay caused by having speakers placed at different distances from the listener. Many of the high performance subwoofers include a phase control device (either switchable or stepless) that can help eliminate mechanical and electrical phase differences between the satellites and the subwoofer.
If the subwoofer is closer to the listener than the speakers, some delay compensation will be required to achieve proper time alignment. Although some bass monitoring or surround sound systems include this feature, not all listeners use it.
Tips for creating home sound
BIdeally, the subwoofer and sound system should be aligned using proper acoustic measuring equipment. When it comes to subwoofer placement, there are a few important things to consider:
- Before you make a subwoofer with your own hands (photos are posted in this article), you need to choose its position in the room. Of particular importance is its proximity to walls, which significantly affects the frequency and time response. If there is no delay compensation, the sub should be placed at the same distance from the listener as the satellite speakers.
- You need to place a separate subwoofer in front of the listener, not behind. It should be away from corners, not placed in the center of a wide room, to minimize the excitation of sound waves. The closer the subwoofer is to the wall, the more bass will be boosted.
- Some models are designed to be mounted next to a wall, and small changes in distance from the wall can make a big difference in deep bass balance, so the user should not be afraid to experiment.
- In order for the subwoofer to work properly and not be localized, the crossover between satellite and subwoofer must be set below 90Hz, which means the satellite should ideally have up to 70Hz or so. Anything above this starts to invade the midrange and the subwoofer will become localizable.
Correct sound system connection
Before making a subwoofer your ownhands for the house, you need to check the calculated output power. After manufacturing the device, it is necessary to check the calculated and actual power. It will depend on the supply voltage and speaker impedance.
Check order:
- Set the subwoofer to listening position with approximate filter and volume settings of 85Hz and a volume that seems right.
- Play a collection of music tracks with well-recorded bass lines in different keys.
- Create your own test track with a sound generator or keyboard, playing every note at even speed settings.
- Experience, listening at every potentially practical subwoofer location, find a position that creates a consistent and natural bass sound, where the sound is well balanced and all bass notes are fairly uniform.
- Optimize subwoofer level and filter wrap-around frequency and phase/delay. These controls are usually interactive, so experiment with their settings and find the best combination.
- If the deepest and highest bass notes seem right, but everything goes wrong in the crossover area, then you need to adjust the crossover frequency up or down to find a smooth transition.
- If possible, adjust the phase control.
Be careful though: adding a subwoofer will inevitably cause some deep bass to annoy your neighbors. Generating very low bass can alsocreate standing waves in the room, and this will cause different parts of the building to rumble and resonate.
Home theater function
Subwoofers are generally easy to connect, given that only two cords are typically used. One for power and one for audio input. There are several ways to connect a subwoofer to an amplifier, receiver, or processor (also known as a home theater receiver).
The preferred way to connect a subwoofer is through the output of the receiver (referred to as SUB OUT or SUBWOOFER) using an LFE cable (an acronym for low frequency effects). Almost all home theater receivers (or processors) and some stereo receivers have this type of output.
The LFE port is a special output for subwoofers only. The user will see it as SUBWOOFER, not as LFE. Simply connect the LFE jack (or subwoofer output) on your receiver/amplifier to the Line In or LFE In jack on your subwoofer. This is usually just one cable with RCA plugs on both ends.
RCA stereo amplification outputs
Sometimes you may find that the receiver does not have an LFE subwoofer output. Or it may happen that it does not have an LFE input. Instead, the subwoofer may have left and right (R and L) stereo RCA jacks. If RCA cables are used in the Line In of the subwoofer, connect an RCA cable and select the R or L port on the subwoofer. If the receiver has both RCA output connectors, be sure toboth must be enabled. This process is the same as connecting a basic stereo speaker.
Before you make a subwoofer with your own hands, you need to clarify the channels. If it has two sets of spring clips for the speaker output, then it means other speakers are connected to the subwoofer and then to the receiver to pass through the audio signal.
When it only has one set of spring clips, the subwoofer will need to use the same receiver connections as the speakers. The best way to achieve this is to use secure clamps, as opposed to overlapping bare wires that can make dangerous contact with each other when connected.
Optimizing the sound of your stereo system
Subwoofers are used in most home theater systems and can dramatically improve the sound of stereo systems. They can provide the foundation for the sound, so adding a sub isn't just about adding deep bass. Rather, they can improve the overall sound of the system.
Connecting a subwoofer to a two-channel system is different from the methods used in home theater systems. AV receivers have a bass management function to send low frequencies to the sub, and midrange and high frequencies to the speakers. The subwoofer connects to the receiver with a single connection cable.
Stereo receivers, preamps and built-in amplifiers rarely have subwoofer output jacks or offer bass management options. Therefore, instead of using these connections, you can use speaker levelssubwoofer, as well as "high level" inputs.
Sub no amp
Most subwoofers are designed to operate without an amplifier. They have a high level input (sometimes called a loudspeaker level input) that connects to loudspeakers. All you have to do is run another pair of speakers from the amplifier output to the high level input on the subwoofer.
This connection works the same as a subwoofer preamp output. It takes the voltage from the amplifier as a signal. And sends it to the subwoofer. It does not consume any power from the amplifier it is connected to and is a common signal with the main speakers, not the power of the amplifier. And since there is no power, all impedances remain unchanged.
The most prestigious REL subwoofers are made in England. They are the "gold standard" of the industry, costing over $9,000! Music lovers don't have to spend that kind of money, as building a subwoofer has become much easier in the age of the Internet.
