[Simple question of car audio] What about the powered type of subwoofer?

For those who have felt "difficult to understand" in car audio and have kept it away, this special feature presents explanations to eliminate the "difficulty in understanding". Currently, the theme is "subwoofer". This time, we will focus on "powered subwoofers".

With "Powered Subwoofer", you can easily enhance the bass!

When you want to enhance the bass, there is an item that you can easily do it. That is a "powered subwoofer" (sometimes called a tune-up subwoofer). This time, I will explain what this is and how effective it is.

Now, when trying to reproduce bass, a speaker unit with a large diameter, that is, a "subwoofer" is required. As I explained earlier, most speakers that can be attached to the door are up to 17 cm class, and speakers of that size cannot reproduce the lowest sound.

However, even if only a single "subwoofer unit" is prepared, no sound can be produced. You need a box to mount it, and you also need an external power amplifier to power the "subwoofer unit." However, with a "powered subwoofer", you can make sound with just this. Because this is a product that integrates a "subwoofer unit", a box, and a power amplifier.

By the way, at this time, I will explain why you need a box. The reason is "I want to trap the sound emitted from the back of the speaker".

Because the speaker moves the diaphragm back and forth, which vibrates the air and transmits the sound, but the work is also done behind the speaker. So, the sound emitted from the front side and the sound emitted from the back side are the same as you can hear with your ears.

However, the relationship is exactly the opposite for sound waves. Looking at the speaker from the front and looking at it from the back at the moment when the diaphragm is moving to the front side, the diaphragm is in a retracted state. Since the movements are in a “pair” relationship in this way, the movements are reversed 180 degrees even as sound waves.

If you prepare a box and trap the sound on the back side in it ...

So, if sounds that are in the opposite relationship as sound waves are mixed in the same space, a certain problem will occur. It's "cancelling". In other words, a phenomenon occurs in which each other cancels each other out. But if you attach it to the box and trap the sound emitted from the back side inside the box, "cancelling" will not occur. Therefore, a box is needed.

In addition, I would like to explain why an external power amplifier is required. The reason for this is also quite straightforward. The reason is that "the built-in power amplifier of the main unit cannot drive a speaker with a large aperture" (some main units can also sound a subwoofer, for example, DEH-6600 of Carrozzeria). The door speaker can also be driven by the power amplifier built into the main unit, but the "subwoofer" has a large caliber, so a large amount of power is required to make it sound. Therefore, in most cases, some kind of external power amplifier is required.

By the way, there are many small and thin models of "powered subwoofers". If such a thing is selected, it can be installed under the seat, and cost saving can be realized in the installation.

By the way, the price of a "powered subwoofer" is in the 10,000 yen range at a reasonable price. Looking up, there are many high-end models, but I wonder if models from 30,000 yen to 50,000 yen are often selected. Compared to buying a subwoofer unit, making a box, and even preparing an external power amplifier, the cost advantage is considerable.

You can get a sufficient effect in terms of sound! There are various options!

Now, the question is "how about the sound?" Even if it is hard to cost, it is meaningless if the sound is not good.

Let's start with the conclusion. The "powered subwoofer" is also effective in terms of sound quality.

By the way, there are few cases where a "powered subwoofer" is used in a vehicle that tries to maximize the sound of participating in a sound contest. In other words, when the emphasis is on sound quality performance, the "unit subwoofer" is advantageous.

However, it is an undeniable fact that even a "powered subwoofer" can produce ultra-bass sounds that cannot be produced by door speakers. And if you control it well, you can hear the deep bass right in front of you. This kind of Hi-Fi-like sound make-up can be done more than enough.

There are various types of "powered subwoofers". Therefore, you can find the best model for you by weighing the budget, effect, and installation convenience.

For example, if you want to get the best bass possible, choose a higher-grade "powered subwoofer," and if you're willing to sacrifice some trunk loading space, a larger model. If you select, you can get deeper and heavier bass. On the contrary, you may choose a reasonable compact and thin model by sticking to cost saving and space saving. Let's consult with the shop and select the product that seems to be the best.

This time, I will end here. Next time, I will continue to explain about "subwoofer". looking forward to.

Shozo Ota | Writer After graduating from university, worked for a publishing company and gained a career as a magazine editor. After he was the editor-in-chief of car magazines, interior magazines, and car audio magazines, he retired from the company he worked for for about 20 years and became freelance. He is developing a wide range of writing activities centered on car audio, car navigation, and other car electronics related items. He is also involved in music activities as a life work.