In addition to traditional objects such as melon seeds, drinks and masks, it is recommended to connect headphones or Bluetooth audio if possible, which will help to absorb toxicity better.
(Photo: Studying in Germany in 2003, like a mouse falling into a rice jar, pulling weeds and saving a simple car stereo for himself, put it in the dormitory to listen to music. Without the special power supply of 12V, the built-in transformer of a desk lamp was successfully transformed into DC power supply. If you can't afford four speakers, buy two universal speakers first and listen to them as a two-channel bookshelf stereo for the time being; If you can't afford professional wires, use ordinary ones ...; Unable to adjust the equalization, I used my own DIY headphone amplifier for pre-amplification)
(Photo: For better effect, a pair of speakers must be made. Wine boxes don't need wooden boards. Fortunately, Germans use solid materials in all aspects, and the sound quality of corrugated boxes is almost as thick as that of thin-layer boards. The sanitary paper core is also made of thick material, so I found two low-frequency catheters.
(photo: finished product drawing. In order to increase the weight of the box and reduce unnecessary resonance, each speaker is pressed with a book of about 2kg.
(Photo: Later, a girl from China moved in and became my neighbor. She found that she likes listening to music very much and always wanted to buy a set of speakers, but she didn't know what to buy. So I spent two weeks quietly making a "simple version of the computer stereo" for her. In the past two weeks, I spent most of my time rummaging through the electronic waste in the downstairs of each dormitory, looking for waste components that can be used. Doing electronic DIY in Germany is more troublesome. Without such a large electronic market as Zhongfa and Zhichun, it is difficult to buy components, and only some common resistors, capacitors and soldering irons can be bought in the "electronic lovers' shop" on the street. Fortunately, I found a repairable 14V/3A power supply. In order to make the components easy to buy, I chose the class A power amplifier route in my design. Although the power amplifier in the figure is small, it integrates power supply noise suppression, preamplifier, frequency response compensation, bass enhancement and power amplification. The only drawback is that it is "warm" to use. )
(Photo: Later, the neighbor from China became the current Nuosao. This is the speaker unit I made for her. Because the power amplifier is easy to generate heat, I chose a speaker with high sensitivity, so that I can achieve the same auditory effect with less output power and little distortion. Later, the box was beautified by Nuosao into the above picture, and the widowed temperament of the science and engineering man disappeared ~)
When we returned to China in 2004, we also brought this stereo back. More than ten years have passed, and I have no time to go deep into audio-related objects. Today, I belong to my old job. Please correct me if you have any improper comments.
A good stereo allows you to "see" with your ears.
Like the engine, every car has a set of stereos, some of which cost only a few hundred dollars, while others cost tens of thousands. Most car stereos are not strictly called stereos, but just car broadcasts, which can be connected to mobile phones, and listening to something while driving will not be boring. Really good acoustics must be designed and adjusted in combination with the special carrier of automobile, including hardware, software, material selection, matching and compatibility with body design.
Just like this GLC Berlin voice, it gives listeners a sweet, moist, loose and shiny sound. It may be hard for you to imagine why you can use these words to describe a set of stereos just by reading posts, but like other high-end original car stereos, it really did.
Besides the Voice of Berlin, there are other high-end car audio brands that you are familiar with, such as Dana and Bowles. & amp？ Wilkins), Platinum Ao (Bang? & amp？ Olufson), Harman Kardon, Bose, Meridian, Mark levinson, etc. There are all kinds of popular science articles about these audio brands and even want to rank them. Personally, I think it is difficult to compete with brands in the same camp. Each brand also has various grades of products. The key depends on the final performance of this product. Next, I will talk about the difference between car stereo and home stereo.
Burning point 1: improve the noise performance of the whole vehicle.
A big difference between sitting at home and listening to the stereo is that the car itself is a noise source, and engine noise, transmission system noise, tire noise and wind noise will interfere with the listening environment. If the foundation of this car is not good, the efforts of sound engineers are basically in vain. The first task they face is to find a car with low overall noise level and good sound insulation effect.
Friends who have done NVH know how many engineers' efforts and R&D's financial resources are hidden behind reducing the noise inside the car 1db. If this is a simple task, then everyone can finish it quietly. Take my previous adjustment work as an example:
Before writing "Nuo Nuo Who Loves Cars", the whole team was dealing with the powertrain test, which was also one of the biggest noise sources on the car. Every car company hopes that the next generation of models will not hear any noise from the engine and gearbox, but as long as the internal combustion engine is used, it is inevitable that the explosion in the cylinder will be repeated. The vibration generated by combustion will look for any audible links along the transmission system and its accessories (similar to audio signals looking for "speakers"), and noise will be displayed in these links and then transmitted to people's ears.
In order to reduce the noise people hear, our first task is to reduce the vibration generated by the engine. One of the most effective solutions is to provide a buffer at the output end of the crankshaft to minimize the vibration transmitted from the crankshaft to the gearbox. For example, the shock absorber on the driven plate of special clutch, such as changing the solid flywheel into a dual-mass flywheel, or even adding an extra movable mass on the dual-mass flywheel to absorb smaller speed pulsation; Other work also includes optimizing the stiffness and damping of components connecting the engine and gearbox, such as suspension (commonly known as engine foot), pipeline, joystick and so on. Of course, there are also noise barriers and local reinforcement of the car body.
(Photo: Work with engineers to study the NVH promotion potential before the launch of new models. Can you tell what kind of car it is? )
In fact, in many cases, the improvement is a combination of the above schemes, but almost no manufacturer can keep the cost of "full living", so we must closely combine the cost space of manufacturers to choose the "most effective improvement scheme combination".
This is very similar to the "repair plan sheet" we implanted in the car wash and self-operated car business today. The Nuo powder that bought a car from us knows the star maintenance plan list. Its key value lies in telling you how to spend money on the cutting edge, which is also a continuation of our past work tasks on used cars!
For NVH test engineers, driving a car immediately knows how valuable it is. GLC has a very good foundation on NVH. When driving normally with the throttle on, the engine sound introduced into the car is very small. Even when the start-stop system is working, the engine stops without induction, and the engine vibration is quite weak when the brake is released, and the NVH level is first-class. In addition, fetal sounds are also filtered very well, which is completely in line with the quiet and calm performance of Mercedes-Benz DNA. Being able to make the car foundation like this, I invested more energy and cost than a set of Berlin voices, so I put it in the first place.
If you don't listen to anything in such a long-distance car, at least it's easy to fall asleep.
(Photo: There are few so-called common faults in this model of GLC, except for the brake pads with more online complaints. I have really experienced it, to be precise, "the rear brake pad makes occasional abnormal noise at low speed in cold state". This situation may occur when you control the brake pedal to creep when moving the car, and it must be at a certain speed point. In my opinion, this is not a problem, the probability of occurrence is low, and this speed range can be deliberately avoided. In addition, because of the good sound insulation effect of GLC, Nuosao rarely opens the window when driving, and has not noticed any abnormal brake noise so far. )
Ignition point 2: rich in details and wide in dynamic range.
Voice coil people like to use "look" as a metaphor for "listen". There are indeed many similarities between these two feelings. Good voice can really make you feel immersive and "see" singers and bands. Such reduction degree must consider two important indicators: dynamic range and detail.
These two indicators are not related to each other, but they are easily confused. Let me give an example of dynamic range. You try to shout "ah ~" at different volumes, and the range between the lowest and the loudest is the dynamic range of your shouting "ah".
Ok, back to audio equipment, the dynamic range that audio equipment can display is much wider than our voice, but there are also differences. Some stereos can't hear the drums of heavy bass, or the singer's breathing and slight tooth-touching sound. It is because these sounds are beyond the dynamic range or optimal display range of the playback device that you can't feel them. Usually, they are "easy to lose details", so "insufficient dynamic range" is easy to "detail"
Next, what is the real "detail expression"? The most common situation is the palette of Office. If you want to choose a font color quickly, you can go to two different pages (as shown below): standard and custom. The former has a choice of less than 180, and the latter has a possibility of 255 cubic meters, which is obviously a case of "more details"!
(Photo: OFFICE's standard color selection card)
(Figure: OFFICE's custom color selection card)
Digital signal processing technology has been widely used in car audio. At the same time, in order to reduce fever, most class D power amplifiers are used. Any system that crosses from analog era to digital era will face a common problem-"resolution". A better sound system will use a higher number of bits and a smaller step size to identify, process and reproduce signals, so as to be close enough to the real recorded acoustic scene.
(Photo: "Qin Wang points soldiers")
You can search QQ Music (Jiangzhou Drum Art Troupe of Shaanxi Province) for a song called "Qin Wang Dian Bing" and try to play it on the car stereo. This piece of music can test the detail resolution of the sound, whether the drum is full of energy every time, especially after each heavy blow, a small group of metal vibrations will be heard and will soon stop. Professionals told me that this is the aftersound of the impact vibration between the "copper ring" on the side of the drum (the handle of lifting the drum) and the fixed ring, which was ingested at the same time when recording.
In order to show the details to such an incisive degree, every link except the sound source, preamplifier, power amplifier, wire harness transmission and speaker unit should not be a bottleneck, but must be unimpeded, because that little detail may be lost or submerged in the turbulent main melody, and all previous efforts will be wasted. If your device can even display this sound, congratulations, this performance estimate is 1 10,000 yuan!
Burn money point three: sound stage's camp?
Focus! Focus! Focus! Knock on the blackboard ...
The so-called sound field is to restore your sound environment through the arrangement of speaker units and acoustic technology. The closer this environment is to the scene environment when recording at that time, the more successful it will be! Many experts also like to call the sound field restoration ability of sound "image binding". The sound source is firmly condensed in a certain position like an image, which is a good voice. This statement is intuitive.
It is relatively easy to create a better sound field when we are sitting at home listening to music. We have enough distance of several meters to place the speakers so that we can sit in the best listening position (the emperor's position). The rest is nothing more than reducing and controlling the sound wave reflection in the room, controlling the aftersound and arranging the furniture reasonably.
(Photo: the most basic schematic diagram of the emperor's throne, 2. 1 channel, the picture comes from "Literature Network")
In the car, we don't have the conditions to design the interior of the sound. The stereo must adapt to the existing cockpit conditions, and even the best brand is not good. This is another critical moment.
When we close our eyes, we can still distinguish the direction and distance of the surrounding sounds, mainly because we have two ears and a complex outer ear, and we have been constantly adapting and calibrating them in the past years, which is called "binaural effect" in acoustics and physics. Once we use fixed speakers instead of real objects, this binaural effect will easily fail. This is why many times we just feel "Look, that horn is making a sound". If you play a CD in the car, you can clearly feel that the music is coming from a speaker in the car, then this is a failure case of sound field construction; If the sound of percussion instruments is intermittent, making you mistake it for noise coming from the cabin (there can be no speakers in the cabin), that is a good sound field!
Excellent car stereo must rebuild "binaural effect". No matter in which country, the driver sitting on one side of the car will make the sound of the left and right speakers reach his ears at the same time, thus destroying the original binaural effect.
(Figure: Measured distance from the main speaker to the driver's ear on the mini-car)
What engineers need to do is to make the left speaker work more or less in the back according to the real distance from the center of each speaker to the driver's ear, and finally ensure that the sound waves reach the human ear at the same time. Smart As shown in the above figure, the ear distance between the left and right ears is 0.5m If the sound speed is calculated by substituting 344m/s, the left speaker should deliberately lag behind the right speaker 1.5ms, and the volume should be reduced appropriately, so that the driver can feel the ideal sound field. In a wider car, the time difference that needs to be deliberately created is larger. When there are more speakers, the sound field improvement brought by this compensation scheme will be more effective.
(Figure: In order to give the driver a good sound field, the left IF speaker must work 1.5ms later than the right IF speaker, as if the left front speaker were installed at the same distance as the right speaker. )
In the application of four-door car, there are speakers on each door. At this time, the farthest position from the driver is the right back door. After the time difference is corrected, the system will calculate the delay time of all other speaker signals based on this "farthest unit".
(Figure: Delay Correction of Multichannel System)
Sound waves are mechanical waves generated by compressed air. Besides arrival time, there is also a phase theory. Similarly, if the sound waves heard by our left and right ears are out of phase, it will also affect the brain's localization of sound. If not corrected, such a phase error will also occur on the car stereo, which will bring us a wrong sense of sound field restoration.
The most troublesome thing is that the phase compensation technology must also set different parameters for different frequencies. This is a lifelong challenge for the home stereo. Fortunately, with a powerful data processing system (DSP), engineers have the conditions to manage and correct every upcoming vibration of the speaker (654.38+ million correction opportunities per second), thus ensuring the reproduction of a theater-like sound field in a small, complex and asymmetric listening room of a car.
If you have a CD of Beethoven's symphony, the Voice of Berlin can let you hear the general orientation of each instrument, which instrument player is closer to you and which one stands taller. You won't even notice where the speaker is. Close your eyes, and you will see the whole orchestra in an arc of120 in front of you, which is warm and melodious.
The restoration of the sound field by the Voice of Berlin can be described as precise and grand. Once, my cat watched a movie (Titanic) in the car after class. Huihong's musical atmosphere actually made me cry. Unfortunately, the screen of the mobile phone is too small, otherwise the audition effect is first-class, and I would rather listen to the battery. You can try the following song if you don't believe me. In order to prevent everyone from making mistakes, just long press the identification QR code. Note that after 0'54 ",the sound comes into play, and the background drum keeps up with the details.
(Photo: The soundtrack of Titanic, Never? Ann? Pardon ")
How do you know that the DSP of Voice of Berlin has this function? Simple! Look at the sound field setting, it can set the driver as the emperor, or set the front and rear rows as the emperor. All deities are optional, and all of them are corrected by DSP sound field algorithm. It's just whether the correction is good or not. You should listen to it with your own eyes and see if there is a band feeling in front of you, instead of the instruments being crowded on the A-pillar or some speakers.
For the technology of multi-passenger throne creation, it is a higher-order DSP correction technology. The basic acoustic principle is the same as that of double speakers, but it is suitable for systems with more speakers.
(Photo: The Voice of Berlin is set to "please all passengers")
Tip: Low-end audio often has a feeling that "the sound is coming from here", because the speakers are often arranged in the front and bottom of the car door. Turn up the volume. Singers and announcers seem to be singing and talking under your knees. This is a typical false sound field.
Let's talk about a "lingering sound" first, that is to say, the feeling that the lingering sound continues to reverberate in the room is somewhat similar to what the ancients said. Do you remember the movie Infernal Affairs? Inside, the two eldest brothers bravely listened to Cai Qin's sister's drama "Forgotten Time", and this song is the most appropriate. When "Who ~ ~" floated out of the quiet speaker, the half-second behind "Who" seemed to be the effect of lingering sound. Listening to this song at home or in the audition room does have the effect of sound waves bouncing briefly between the ceiling and the floor, but there is no such bounce at all in the car (it is sound-absorbing from top to bottom).
(Photo: Classic Audition Music-Cai Qin's "Forgotten Time")
(photo: stills of the movie Infernal Affairs. If you are interested, you can review Cai Qin's famous audition song "Forgotten Time", which you can never get tired of listening to. )
What shall we do? If you want to create this audition effect in the car, make some residual noise artificially ~! To what extent is it suitable for manufacturing? It all depends on Andhadhun's aesthetic and brand style. If this just hits you, then the Voice of Berlin is very suitable for your choice. So there is no absolute standard to say which brand of audio will surpass which brand, or it depends on which one is more suitable for your taste. The difference between high-level players has been difficult to measure by technology.
Come to an end for the time being
Have you ever found yourself writing 6000 words, and you can't stop the car when you say dry goods? Car audio is a very interesting field, and the challenges it faces and the space it can do are bigger and more interesting than home audio systems.
A carefully tuned and designed car stereo is actually worth spending money. After all, cars produce a lot. Once a high-quality audio manufacturer becomes the designated original supplier of a car brand or model, the sales volume is now much easier than that of home audio, so many one-time costs can be diluted well, and many exterior accessories needed by home audio do not need to be made. Just ask the car body and wiring harness manufacturers directly, and the power can be lower than that of home audio. It is precisely for these reasons that instead of adding a car to the living room at home, it is better to buy a car to enjoy the sound of Berlin.
Well, there are a lot of interesting sound knowledge and fascinating listening to songs. I will talk about it in the second part. Pay attention to personal protection and exercise properly. May everyone have a happy new year, and all poisons will not invade!
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.