The role and significance of subwoofer in home theater components

The role and significance of subwoofer in home theater components

The function and significance of the subwoofer

ge-diameter unit also requires a high-power amplifier, which will increase the cost of restoring the subwoofer. Of course, we can also buy subwoofers with low sales prices in the market. This is actually another kind of compromise. Technically speaking, it is just a fake subwoofer, but from the perspective of the commodity and consumer market, this is also a market preference. need.

Active Subwoofer vs Passive Subwoofer

As mentioned earlier, the subwoofer requires powerful power to drive, so most subwoofers on the market have built-in amplifiers, that is to say, the speakers and amplifiers of the subwoofer are independently divided and integrated into one. If there is no amplifier in the subwoofer, it is a passive subwoofer.

Strictly speaking, the subwoofer should use a large-diameter unit, and generally a specially designed unit. According to the actual listening comparison of various subwoofers at home and abroad that have participated in the evaluation, the effect of this large-diameter subwoofer is the best.

However, the market needs are multifaceted. Under certain conditions, it is impossible to place a large subwoofer. In addition, some consumers also like small and compact products, so there is a small subwoofer. This kind of subwoofer is usually obtained by technical means, such as Boss and Yamaha. The former is the technology of box design, and the latter is the technology of circuit design. But no matter how shocking this kind of subwoofer is, the "fake" in it is hard to hide. Please understand the "fake" I said accurately, and don't spread it, so as not to cause unnecessary misunderstandings and misunderstandings.

With so many subwoofers being used in home theater systems, subwoofer designs are becoming increasingly simple, and this simplicity seems reasonable. Strictly speaking, the subwoofer can only restore the subwoofer signal, so in the early subwoofer design, 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 does not enter the subwoofer. The amplifier behind it and interferes with the operation of the subwoofer.

In the digital home theater audio decoding specification, the output 0.1CH signal itself is already a subwoofer signal. Therefore, for newer systems, 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. Therefore, it is not necessary In order to achieve multi-purpose and multi-purpose or competition needs, a low-pass filter is designed in the subwoofer, 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, and it is possible to connect 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.

The critical point of the low-pass filter mentioned above is the cut-off frequency of the subwoofer. In order to increase the adaptability of the subwoofer, the cut-off frequency of many subwoofers is adjustable.

The setting of this cutoff 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 will be perfect. If the connection is not good, some signals will be lost or the signal will be destroyed. It's changed.

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. It usually depends on the lower limit of the low frequency restoration of the speaker.

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, and 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.

Phase (English phase): Most subwoofers are designed with a phase adjustment switch in the home of audio speakers, and the phase adjustment of advanced subwoofers is still continuous. Phase adjustment is relatively simple, positive phase or reverse phase. The correct setting should be that the sound of the subwoofer is relatively strong and shocking. If the sound becomes ethereal after the subwoofer, then the phase switch should be changed immediately.

Connection: Professional website navigation: For home theater systems, it is recommended to use low-level signal input for subwoofer signals. 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 the amplifier has no subwoofer output terminal, we recommend connecting it from the AV amplifier, which can be The subwoofer volume is controlled synchronously by the AV power amplifier. If it is taken from a disc player, when the system volume is changed, the volume of the subwoofer needs to be adjusted at the same time. This kind of connection, usually in stereo mode, the subwoofer can't get the signal, so it doesn't help or improve the system much, this needs to be paid attention to.

If you are trying to get a full-band signal from a stereo signal into a subwoofer, you must first make sure that your subwoofer has a low-pass design, otherwise, the subwoofer cannot be used. In this case, the subwoofer of any program can be enhanced.

Placement: Strictly speaking, the subwoofer lacks directionality, so it can be placed anywhere in the listening room, but considering the huge impact of the environment on sound transmission, we still strongly find that moving the bass The position of the subwoofer has a great influence on the restoration of the subwoofer. Generally, the subwoofer is placed at one-third of the front wall. Effect.

Finally, it should be noted that the subwoofer does not always exist in the program source, so don't misunderstand it when listening or debugging. Because of habits, people will inevitably use their ears to hear whether the subwoofer is working or whether it is shocking when debugging. In fact, it is unnecessary, and it is enough to feel it with the body. In order to facilitate debugging, special subwoofer signals are usually provided in the test discs on the market.