The Significance of a Home Theater Subwoofer

                           The Significance of a Home Theater Subwoofer

We have also introduced the importance of subwoofers before, and many netizens are also consulting about subwoofers, so we will organize a knowledge article about home theater subwoofers, hoping to be helpful to all enthusiasts.

1. The function and meaning of the subwoofer

Subwoofer is also a common name or abbreviation for this type of speaker. Strictly speaking, it should be: subwoofer. As far as the audio analysis that can be heard by the human ear is concerned, it consists of subwoofer, bass, bass, midrange, midrange, treble, and supertreble.

In simple terms, low frequency is the basic framework of sound, mid frequency is the flesh and blood of sound, and high frequency is the detailed response of sound.

With the development of science and technology and the development of economic base, subwoofer and broadband have also entered the world of audio. The structure of subwoofer is strengthened, and broadband is to make the sound difference more clear.

This time we mainly talk about super heavy speakers. What people can hear with super heavy bass is limited. Instead, other senses of people can feel it. Generally speaking, the subwoofer only exists and is restored in a specific program source. With it, the program source can be restored more realistically. Without it, it will give people a feeling of lack of power and energy. For example, in a movie theater or in reality, we can feel the power and energy shock of an airplane taking off, but if our home theater is not equipped with a subwoofer or the configuration is unreasonable, we will not be able to feel this shock for a long time.

As far as the audio environment is concerned, whether it is listening to music or watching movies, subwoofer is needed and should be guaranteed. The delineation of 0.1CH as the subwoofer channel in the two major audio restoration standards of digital home theater also shows its The meaning and function are necessary, but they can also be compromised.

Why compromise?

Because of the restoration of subwoofer, as a standard drafter, of course, we understand that it is difficult to popularize, because the cost is relatively high, and without other technical support, the unit for bass reproduction should be large-diameter, and drive this large-diameter The unit also requires a high-power amplifier, which will also lead to a sharp increase in the cost of the subwoofer.

Of course, we can also buy subwoofers with low sales prices in the market. This is another compromise. Technically, it is just a fake subwoofer. need.

2. Active subwoofer and passive subwoofer

As mentioned earlier, the subwoofer requires a lot of power to drive, so most of the subwoofers on the market have built-in amplifiers, that is to say, the speakers and amplifiers of the subwoofer are independently divided and integrated together.

If there is no amplifier in the subwoofer, then this is a passive subwoofer.

3. The unit diameter of the subwoofer

Strictly speaking, the subwoofer should use a large-diameter unit, and it is generally a specially designed unit. The effect of a large-diameter subwoofer is very good.

But the market demand is multifaceted. Under certain conditions, it is impossible to place a large subwoofer, and some consumers prefer small products, so small subwoofers appear. This kind of subwoofer is usually a technology No matter how shocking this kind of subwoofer is, the "fake" in it is hard to hide.

4. Description of the frequency division circuit of the subwoofer

With the abundance of subwoofers used in home theater systems, subwoofer designs are becoming simpler, and this simplicity seems reasonable. Strictly speaking, the subwoofer intelligently restores the subwoofer signal, so in the early design of the subwoofer, the front end is usually designed with a low-pass filter crossover circuit, which is to filter out the signal higher than the subwoofer so that it cannot enter the rear. amplifier and interfere with subwoofer operation.

In the decoding specification of digital home theater audio, the output 0.1CH signal itself is already a subwoofer signal, so for a relatively new system, whether the subwoofer has a low-pass filter or not has no effect on the operation of the subwoofer.

For those who try to use the subwoofer in the two-channel music system, because the usual signal source or power amplifier does not have a separate subwoofer signal output, it is necessary to extract the subwoofer signal on the basis of the existing system , so many subwoofers are designed with a low-pass filter in the subwoofer for multi-purpose use or for competition needs, and two extraction methods are designed:

1. It is extracted from the low-level signal output of the signal source, usually an RCA input port, which can be connected with a pair of signal lines or a single signal line.

2. To extract high-level signals from the left and right speakers, generally use the same terminals as the speaker terminals on the power amplifier. As above, the effect of using two pairs of thinner speaker wires or a pair of speaker wires is basically the same.

5. Setting of cut-off frequency

I mentioned before that the critical point of the low-pass filter is the cut-off frequency of the subwoofer. In order to increase the adaptability of the subwoofer, the cut-off frequency of many subwoofers can be adjusted.

The setting of this cut-off frequency is an important debugging environment for playing subwoofers. It is used to debug the frequency connection between the subwoofer and the speakers. If the connection is good, the system performance is relatively perfect. If the connection is not good, either the signal is lost or the original signal will be destroyed. face.

Generally speaking, for bookshelf boxes and small-diameter speakers, the cutoff frequency should be higher, and for floor-standing speakers, the setting should be lower, usually depending on the lower limit of the low-frequency restoration of the speakers.

For example, if the lower limit of the low frequency of a speaker is 60Hz, it is more reasonable to set the cutoff frequency of the subwoofer at 60~80Hz. If it is too high, the bass at 60Hz will be too much. If it is too low, the energy of the 60Hz signal will be lost. .

For digital home theater power amplifiers, the power amplifier itself has bass management settings, and the cut-off frequency settings of the subwoofer are adjusted in combination with the size settings of the speakers.

6. Phase

Most subwoofers are designed with a phase adjustment switch, and the phase adjustment of advanced subwoofers is continuous.

Phase adjustment is relatively simple, normal phase or reverse phase. The setting you strive for should be that the sound of the subwoofer is relatively strong and shocking. If the sound becomes ethereal after the subwoofer, you should change the phase switch.

7. Connection

For a home theater system, it is recommended to use a low-level signal input for the subwoofer signal. Usually, there are two choices, one is the multi-channel output from the disc player, and the other is the subwoofer output from the AV amplifier, unless it is an amplifier. There is no subwoofer output terminal, we suggest connecting it from the AV power amplifier, so that the subwoofer volume can be synchronously controlled by the AV power amplifier. If it is taken from a disc player, then when the system volume changes, the volume of the subwoofer needs to be adjusted at the same time. This connection, usually in stereo mode, the subwoofer cannot obtain signals, so it does not help or improve the system much. This is Need our attention.

If you try to get the full-band signal from the stereo signal to the subwoofer, you should first confirm that your subwoofer has a low-pass design, otherwise, the subwoofer cannot be used. In this case, the subwoofer of any program can be strengthened .

Eight, positioning

Strictly speaking, the subwoofer lacks directionality, so it can be placed anywhere in the listening room. However, considering the impact of the environment on sound transmission, we can still strongly find that the Budweiser that moves the subwoofer It has a great impact on the restoration of the subwoofer. When conditions permit, we still recommend users to adjust the subwoofer position to obtain the best effect.