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🚗 | Release of "Jeep Wrangler Rubicon Soft Top", a limited edition car with "strongest" off-road specifications


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"The strongest" off-road limited edition "Jeep Wrangler Rubicon Soft Top" released

 
If you write the contents roughly
The equipment conforms to the 4-door specification "Rubicon", and is equipped as standard with a heated steering wheel, leather seats, front seat heater, audio navigation system with 8.4-inch touch panel monitor (Uconnect), and Alpine premium speakers with subwoofer. The interior is finished with a high-quality feel.
 

On July 7th, FCA Japan will be a full-fledged offloader for Jeep, a 24-door softt that normally has no settings ... → Continue reading

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Wikipedia related words

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Subwoofer

Subwoofer(English: Subwoofer) Is responsible for playing only the ultra-low range below 100 Hz.speakerIs.In many cases, it is separate from the main speaker system, but in some cases it is integrated.

Overview

Generally, a speaker unit is required to be able to output evenly from bass to treble, but since the frequency band that one speaker can emit is limited, the level gradually decreases in the high and low frequencies. Will end up.For this reason, it is normal for speakers suitable for sounds in the frequently used frequency band to have difficulty in producing high and low frequencies.For this reason, a combination of a plurality of units having different reproduction frequency bands is created, but it is often difficult to reproduce a particularly low frequency range.Moreover, it is often difficult to reproduce sufficient bass with a small speaker.

The purpose of the subwoofer is to make up for this.There are two types, one that enhances the amount of bass in the main speaker and one that adds bass in a lower band that is difficult to reproduce with the main speaker, but rather than having a subwoofer for each purpose, the main speaker It is due to the combination of.The woofer is also referred to as a woofer.

Subwoofer (SubwooferThe sub-) in) is a prefix that represents "lower" and "lower", and is due to reproducing the bass in the lower (lower) band than the main speaker.It also has the meaning of "... supplement", which means to supplement the bass that is lacking in the main speaker.Although it is also called a super woofer, super- is a prefix meaning "above" and "exceeds", and it is appropriate in English as a name for a device that reproduces sound in a band lower than the main speaker. Not to say, it is only used in Japan.This was originallyYamahaIt was the product name of.

The band covered by the subwoofer is generally in the bass range of 100Hz or less, but when used in combination with a small speaker, etc.Cutoff frequencyMay be even closer to the high frequencies.

The single subwoofer that is generally sold is an active type with a built-in amplifier.

Contrary to the subwoofer, the device that is exclusively in charge of the high range that cannot be reproduced by ordinary speakers isSuper tweeterCall.

特性

The subwoofer has two main speakersstereoWhen playing, or 5.1ch etc.Multi channelEven when a larger number of players are used for playback, one unit is often sufficient.There are several reasons for this.

  1. The bass range that the subwoofer is in charge of is compared to the higher range.A human OfHearingSo the source of the sounddirectionIs difficult to catch.Therefore, it is unlikely that even one unit will make you feel uncomfortable.
  2. Since the bass has a large effect on the sound pressure change due to mutual interference, the bass may cancel each other depending on the setting when two or more units are used.
  3. Due to the nature of the subwoofer to reproduce bass, it is advantageous to have a physically large subwoofer.For the purpose of expanding the lower limit of the low range, it is better to combine two subwoofers with half the capacity into one larger one than to use two subwoofers.
  4. Similarly, since it is preferable that the subwoofer is large, it is difficult to install multiple subwoofers, so only one subwoofer is required.

However, there is a disagreement about the reason for 1, and there is an example in which two subwoofers are installed for 2ch playback (in the case of 2ch stereo) because it is claimed that there is a sense of discomfort in hearing.

In addition, the formerDolby SurroundIn (for consumer use), bass reproduction is required only for the front 2ch, and even in modern 5.1ch, when the single-shot subwoofer, which is essential for "0.1ch", lacks bass in the speakers of other channels. It is normal to transfer to (#Home theater systemSee also).

Construction

Like a normal speaker型 型,Bass reflex type(Phase inversion type), horn type, etc. exist.Since the structure is specialized for low-frequency reproduction, the direct sound from the unit is not always important, so the direct sound is completely blocked.ASW typeAlso exists.As a rare exampleBOSEProduct ・ Adopted by CanonResonance tube methodThere is. HoweverAudiophileSome people are particular about direct sound reproduction from the unit, saying that the bass reproduction method using resonance is inferior in sound quality.

In order to add a subwoofer to a general speaker system, it is necessary to use some kind of filter to divide the role of each speaker.Normally, use a channel divider, dividing network, etc.The subwoofer cuts the mid-high range and the main speaker cuts the bass, but the bass cut of the main speaker is avoided because it has an adverse effect on the sound quality, and it may be dealt with only by the mid-high range cut of the subwoofer. is there.

So-called"Luxury audioIn the world called ", etc., after the addition of the subwoofer, the entire system extended flat to the low range.Frequency characteristicFor measurement asmicrophoneThe sound pressure frequency characteristics, phase characteristics, and arrival time from each speaker to the listener are adjusted using the analyzer.In particular, if the bass of the main speaker is not cut, the bass of the main speaker and the bass of the subwoofer may overlap and interfere with each other, which may cancel out the bass. The setting of the subwoofer is important.

In general popular price range systems, it is easy to leave it to the dedicated power amplifier and low-pass filter built into the subwoofer.The so-calledAV amplifierMany of them have a dedicated subwoofer output, and some of the subwoofers of such audio systems are dedicated to the combination.However, if the main speakers are relatively large and reproduce bass that overlaps with the subwoofer, adjusting the interference is reasonably important.

History

The movie "The movie released in 1974" actively introduced the subwoofer into the audio system.big earthquake].In this movieMCA/Universal movieUsing a system called the method jointly developed by Sirwin-Vega, multiple woofers from Cerwin-Vega were installed in the theater to reproduce the ground noise of the earthquake, and the sound effects were experienced by the audience by reproducing low-frequency sound with high sound pressure. I let you.However, this method requires a high introduction cost to the theater, and the content of the program that makes use of such an extremely low range is limited to those dealing with disasters and wars, so the number of productions is small, and a full-scale sub in the theater The introduction of the wooferTHXI had to wait for the standard to be established.

In equipment sound such as PArock musicAs a result of the contradictory specifications of the PA system for portability and expansion of the low-frequency reproduction range, in the 1980s, the method of stacking blocked speaker units for each band was changed to. A style has emerged in which a 2- to 3-way unit is stored in one box, and a subwoofer for enhancing low frequencies is combined in a separate box as needed.This makes it possible to meet the low-frequency reproduction limit, make the PA system portable, and shorten the setup time.[When?]It has become a standard system in.

The introduction of subwoofers into home audio systems has been delayed for a variety of reasons.There was no need to play music software purely, and the difficulty of setup was a major obstacle to its widespread use.There is also an aspect that the understanding of the original low-frequency reproduction was spoiled by the touting of equipment and music that emphasized the sound around XNUMX Hz, which is higher than the range that the subwoofer is in charge of.Realistic reproduction of the realism of the concert hall, ororganWe are particular about perfectly reproducing the sound of instruments with a particularly wide band such asAudiophileThere was a slight introduction by.Alternatively, it was introduced by sound enthusiasts who prefer to play explosive sounds and SL sounds instead of music.

However, with the spread of video software and laser discs, there are more opportunities to play video software such as movies at home, so there is a tendency that bass is essential for playing sound effects, and it is gradually being introduced to homes. It increased.DVDPlayer and software1996When it was released (in the Japanese market), the number of sets sold for home theaters increased, making setup relatively easy and increasing awareness.Starting with that, it has gradually become understood and welcomed that installing a subwoofer can reduce the size of the main speaker and increase the degree of freedom in layout.Therefore, the so-called 2.1ch pure audio system has come to be recognized not only in video software but also in the playback of pure music software.

Direction of using subwoofers

The usage of subwoofers can be roughly divided as follows.

Distinguishing by playback band

  • Bass augmentation of main speakers
It is used to increase the amount of bass when it is not possible to produce a loud volume due to the environment, or to aim for the playback effect of movie software.Therefore, since the bass of the main speaker is not cut, the bass may cancel each other out depending on the setting, which may have the opposite effect.In addition, the difference in bass sound quality between the main speaker and the subwoofer may cause discomfort.
  • Complements the bass in the band that cannot be played by the main speaker
To give a simplified example, if the main speaker can only reproduce up to 50Hz, the subwoofer can be used to supplement the bass below 50Hz.However, in reality, the main speaker can reproduce perfectly at any Hz or higher, but the following is not something that cannot be reproduced at all, and the level gradually decreases.Therefore, when adding a subwoofer without cutting the bass of the main speaker, it is not possible to clearly distinguish how much the amount is complemented and where the band is complemented.When cutting the bass of the main speaker, it can be considered that the subwoofer clearly supplements the bass below the band that can be reproduced by the main.

Distinguishing by combination

  • Complementing small speakers
Sound system for personal computerPortable music playerForActive speakerThere are extreme examples such as.The system configuration is easy to understand, such as making the main speaker ultra-compact so that it can be placed next to the desktop monitor, and installing the subwoofer under the desk.This is the general usage in home stereo,Mini component systemIt can be said that subwoofers that are sold as a set or set as options are also of this type.
However, for a real small speaker with a woofer size of about 10 cm, the subwoofer is in charge of frequencies up to a fairly high frequency, which can be said to be out of the original definition of a subwoofer.There is also a set of mini-speakers and subwoofers that are supposed to be combined with a subwoofer (without considering playback independently).In this case, it is not called a subwoofer, but may be simply called a woofer.These mini-speaker and subwoofer set products are mainly developed and sold by PC peripheral equipment manufacturers, and are for PCs.Sound cardFamous forCreative technologyIncluding,Logitech,Sanwa Supply,Buffalo,ELECOMA wide variety of models are on sale from.
  • Complementing a full-scale large speaker
Even for relatively large speakers, there are some that prioritize efficiency at the expense of the lowest frequency reproduction capability (especially).Back load horn typeIs a speaker with that kind of personality).Even large speakers, which are generally considered to have sufficient bass reproduction capability, may still be dissatisfied with the capability for audiophiles.Subwoofers used for such purposes have become quite large, and commercially available products do not meet the needs of enthusiasts, and there are cases where they are made by themselves or have a huge speaker unit embedded in the wall surface.

Home theater system

5.1ch, 6.1ch, 7.1ch, etc.Home theaterIn the system (surround system), the bass range assigned to the subwoofer is recorded independently (discretely) so that it is represented as each "0.1ch" in the software itself such as DVD video.LFECalled a channel.This is not a matter of mixing the bass range of a 2.0ch channel sound source into 1.0ch monaural and playing it, but the idea that the original sound source is determined by the creator's intention is very different.In ordinary movies, this range is not always used, so LFE is expressed as "0.1ch".

In addition, bass is also included in channels other than 0.1ch, and not all are distributed to 0.1ch.Therefore, in a home theater system, if the main speaker is large and has sufficient bass reproduction capability, the bass will be reproduced in each channel, and the bass will not be transferred to the subwoofer.However, in reality, in home theater systems, there are many cases where a small speaker is used as the main speaker, and bass reproduction is transferred to a subwoofer.In addition, although this is an example, it is also possible to reproduce only the front left and right speakers of the main speakers up to the bass, and to transfer the bass to the subwoofer for the center and rear speakers.

Bass effect

There is a theory that the extremely low range (20 Hz or less) is inaudible to the human ear, but it affects the human body.Low frequency soundCalledEnvironment issuesIt may be taken up in.However, it does not seem to have much effect on general audio.What I would like to be more careful about is the so-called noise problem, such as the sound being transmitted to the neighboring house due to excessive bass enhancement.

Not only is it difficult to insulate the bass in the bass range, but in condominiums and apartments, it is not uncommon for apartments and apartments to travel through floors, walls, and concrete, which is a structure, to reverberate to neighboring houses (sounds like the sound of the earth are generated). ).Subwoofer users should be especially aware that neighbors often have unpleasant situations, such as "I don't know where they come from," as already mentioned.

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