Passive subwoofer in modern acoustic systems

What is a subwoofer? In fact, a passive subwoofer is a column that connects to a computer or speaker system. It is capable of reproducing low-frequency sounds (from five to two hundred Hz). There are subwoofers passive and active. This affects their ability to transmit sound.

For good sounding of an audiosystem it is enough one large column which for convenience can be placed under a table. Choosing the most suitable place for placing a subwoofer, you can make an attempt to extinguish standing low-frequency waves that appear in a closed small room. Most often, a passive subwoofer is used in home theater speaker systems for watching movies with special effects and listening to music. It transmits low frequencies well.

It happens that subwoofer systems do not fit well with the equipment connected to them due to inconsistency of their phase and amplitude-frequency characteristics. To overcome such sound defects, some subwoofers have the ability to adjust the phase and the upper frequency.

Types of subwoofers

There are two types of subwoofers: active and passive. There are questions about what distinguishes the active subwoofer from the passive, what they perform functions in the acoustic systems?

An active subwoofer has a power amplifier built into it . Due to this it is able to remove low-frequency load from the amplifier. In addition, the active subwoofer has an active crossover that allows filtering of high frequencies, helps to reconcile the work of the subwoofer with an acoustic broadband system. Quite often it has additional options for customization in accordance with the conditions of use. It has a tone and volume control.

Unlike the active passive subwoofer does not have an amplifier. It is subordinated to the device to which it is connected: to a computer, to an acoustic system. Therefore, it is combined as a complement to the main stereo speakers. It can be connected to a separate power amplifier. The main disadvantage of a passive subwoofer is that it creates an additional load on the stereo channels, which reduces the volume and dynamics of the sound of the audio system. But, the higher the sensitivity of the subwoofer, the less it loads the amplifier.

The design features that a passive subwoofer has, make it demanding to be placed in a room. It should be moved until a good bass sound is found. The frequency range, which has a subwoofer, can be divided into three types: deep (from twenty to forty Hz), medium (from forty to eighty Hz), and high (from eighty to one hundred and sixty Hz) bass. The sound transmitted by the subwoofer depends on the area of the diffuser. This determines the power and organic nature of the bass.

Subwoofer Designs

On the device passive subwoofers distinguish: horn, bass reflex and strip. They have their advantages and disadvantages. The woofer speaker of the horn subwoofer is located on the wall of the sealed box. Closed types of subwoofers can have large, bulky dimensions, while they have the ability to reproduce a juicy, deep bass.

Fazoinvertornye have a speaker, which is located in the body. Most often there is an opening on one side of it. Subwoofers of such models transmit bass of lower tone than closed speakers, because the diffuser's stroke increases. They are more suitable for large rooms, because they are very loud.

The next kind that a passive subwoofer can have is a striped subwoofer. It is a bandpass filter that combines the properties of the two types described above. This is manifested in the fact that the subwoofer consists of two parts: a closed box and a bass reflex port. Therefore, there is an increase in sound pressure, but the frequency range becomes smaller.

For indoor use, closed-type subwoofers or bass reflexes are more suitable. Choosing them, it is worth paying attention to the following. The amplifier of a subwoofer should exceed in one and a half time capacity which the acoustic system possesses. Compliance with this condition will ensure the sound quality.