WeChat public account search for "large speaker" Original creator: film
JBL Hartsfield
The "audiophile article" that begins with Hi-Fi sound is no stranger to everyone. But what I'm going to talk about today may be a challenge and disruption to mainstream Hi-End perceptions. Hi-Fi is the abbreviation of English High-Fidelity, literally translated as "high fidelity", and its definition is: a reproduced sound that is highly similar to the original sound. However, in my opinion, the "hi-fi audio" that is commonplace in various audio soft texts cannot be truly called "high-fidelity audio", and can only be called "high-level audio" in a strict sense.
The limitations of "hi-fi"
The audio industry began in the thirties of the last century, and after nearly a hundred years of tube and transistor, analog and digital age, a long-overlooked fact is that the fidelity of individual audio products is very low. At this time, there will definitely be a rebuttal sound: high-end sound has achieved the ultimate in the ability to create sound details and the bandwidth rendering that can be heard by people (20~20000Hz), how can it be said that the fidelity is very low? The sound with strong depiction ability shows the nuanced layers in the music, and the sound is very advanced and "fidelity".
But in fact, the fidelity of the replay depends more on whether the "big" aspects of the music are accurate, such as whether the piano cavity resonance accurately expresses the volume of the piano, whether the ratio of wood and metal of the guitar plucked strings is appropriate, whether the bass singing is from the throat or can hear the chest resonance... All of the above can not be solved by doing a good job of details and bandwidth, but also depends on the sense of volume of the mid frequency and the correct proportional relationship between the three frequency bands of the sound, the high, medium and low. In widely used fever articles, the ratio of the three frequency bands of sound and its balance are rarely discussed.
When we look at the first-line and super-first-line audio brands on the market, even their top-of-the-line models, the reproduction of the three-band proportional relationship is far from standardized. Audio source, power amplifier, speaker is an indispensable three parts of the audio system, we take the most standardized power amplifier as an example, there is no lack of top products on the market can reach 20~20000Hz straight frequency response, distortion reaches 5/10,000 or even low unpredictable. However, this is only the test condition to obtain indicators, in the actual use conditions, when driving the target speaker, in the face of the back EMF of the speaker unit, and some difficult to push the high-damping sealed cabinet (such as Shiba Extrema), the thrust of the amplifier can not overcome the damping of the speaker, not only the low frequency can not come out, even the middle frequency will be held. Reflected in the sound of music, the singing person seems to be pinched by the throat and is "singing", so that the three-frequency ratio is unbalanced, and the absurd sound can be said to be "high fidelity"?
On the mid-woofer of the Extrema, the coated damping material can be seen
Extrema's rugged, airtight cabinet (unplugged back-spoke bass mounted at the rear)
Different values in the high, medium and low frequency bands
The importance of high, medium and low frequency bands for musical expression and listening is not the same. The low frequency is used as the lower disc of the sound, presenting the momentum and scale of the music; High frequency expresses the overtones and sound colors of musical instruments, and is the delicate decoration of music; The mid-frequency is the base interval of most instruments and vocals, and it is the foundation and core of music.
Before 1950, due to the limitations of recording technology, high and low frequencies could not be picked up, and the performances of the masters of the Golden Age could only be recorded in the midrange. These incomplete recordings have been repeatedly listened to by generations of music lovers because of their aesthetic value that is difficult for modern performers, and some records are still very expensive and highly sought after today. Is it enough to show that these historical recordings that only record mid-frequency can endure to show that mid-frequency is more important in music listening than high-frequency and low-frequency?
Masters of the Golden Age (mono tablet)
Master playing in the Golden Age (stereo tableting)
In the process of pursuing full bandwidth, modern hi-fi is subject to technical limitations and design trade-offs, actively or forced to sacrifice the midrange, resulting in thinness and flattening of the sound. The flattening of the midrange makes the music lose its infectious foundation and value core, and one can only rely on the decorative nature of the high frequency to provide a beautiful appearance to the sound. This is like a person with insufficient content but redundant dress, wearing expensive and gorgeous coats in vain, but will attract boredom to discerning people.
High frequencies certainly have their value. Considering high frequencies from the perspective of fully expressing music and reproducing musical connotations, appropriate high-frequency extension makes the sound refined. When expressing the multiple parts and complex sound fields of large-scale music such as symphonies, the musical structure can be more three-dimensional, clear, and distinguish hundreds of instruments.
This can be used to explain why people listen to historical recordings of the mono period and prefer quartets and sonatas with a small number of musical components; When listening to large compositions such as symphonies, I prefer to choose stereo recordings that appeared after 1958. However, there is one exception: Furtwängler. All of his symphonies are mono recordings, and despite the limited bandwidth and the absence of delicate high-frequency reproduction of the separation and exact position of the voices, they still move and shock generations of music lovers with their breathy and thorough conducting style, with an eternal and irreplaceable charm. From this point, it is not difficult to see that the connotation of music is greater than the sound effect, and the sound effect should serve the musical connotation, not interfere with it.
Furtwängler's command during World War II
Furtwängler commanded Bejiu in 1951
Tri-band balance is the primary factor for high fidelity
Just as the head, torso, and limbs of the human body need to have an appropriate proportional relationship, the high, middle and low frequency bands of the voice also need to have an appropriate proportional relationship. Some high-end speakers are too pursuing high-frequency meticulousness, and have to be paired with light and thin midrange, and the low frequency connected to it can only be pointed. With such a system, listening to small works makes people feel that they are not "powerful" enough, cannot touch the heart, and when listening to large works want to be thrilling, it can only present "scratching the boot". Many audio high-rollers are complacent about the high-frequency performance of sky-high audio, thinking that exquisite sound is the elegant taste that success and gold can have, and in turn ridicule the "low frequency of smashing the door" as the work of uneducated nouveau riche.
However, the symphonies of composers such as Dvořák, Bruckner, and Mahler all have extremely high requirements for the volume and speed of low frequencies, and Pink Floyd's "The Labyrinth Wall" introduces helicopter landing at the concert scene, and the low-frequency waves brought by the propellers roll in, which is moving. The replay of high-end sound has disabled these great works, how can it be worthy of the word "premium"? In that case, why would high-end audio prefer to choose between the more valuable midrange and low frequency for the sake of the extension and delicacy of high frequencies? As an important factor in the driving force of the horn unit - magnet, the magnetic force of steel magnetism (Alnico) before the 60s is much higher than that used in modern manufacturing units (Ferrite). In the powder magnetic era, it was too difficult to create a mid-frequency unit with superior thickness and texture.
In addition, CDs that replaced vinyl records as mainstream sound sources at the end of the 80s performed dull in midrange, further drawing from the sound source to the bottom of the mid-frequency expression of the audio, so modern high-end audio had to give up the mid-frequency thickness, and take high-frequency extension and delicacy as the fulcrum of their expensive selling price. Is the excessive pursuit of decorative nature in high frequency of modern audio coinciding with the increasingly developed contemporary economy and the excessive refinement of public aesthetics?
(Image from the Internet)
The essence of three-band balance is that the mid-frequency can always be stretched to the balance that is not interfered with and not covered. At any moment of musical performance, whether the music is earth-shattering or as thin as a gossamer, the midrange is the core of the sound and cannot be suppressed or masked by the high frequency at any time. After the sound signal is divided by the frequency divider, the high, medium and low units are sounded separately. Since the sensitivity of the tweeter is much higher than that of the mid-woofer, when the sound signal is very weak, the mid-frequency unit of the unbalanced system does not sound or the sound is extremely weak, while the high-frequency unit produces a large sound, which causes the mid-frequency to be covered by the high frequency when the signal is weak, and the emotional expression of the corresponding section cannot be continued, losing the musical appeal.
The pursuit of an adequate mid-frequency system will face the opposite problem. At the climax of the music, the full-frequency energy is very strong, the high-frequency unit may be overdriven, the sound is furious, and the ear-grabbing sound is equally fatal to the interference and destruction of the musical beauty. Here we have to talk about the non-standardization of audio equipment, the same equipment, at the weakest signal and the strongest signal, the response to the three frequency bands can not be linear. The result of our equipment can only be judged by the sense of hearing, in the weakest tone of the mid-frequency continuous, the strongest tone of the high frequency is not soaring, the sense of low frequency volume can meet the momentum and scale needs of the large orchestra, so that it is a three-frequency balanced sound.
Achieving "high-fidelity" sound is systems engineering
As mentioned earlier, each piece of equipment in the audio system is non-standardized, and changing any piece of equipment will change the sense of volume, expression and proportion of the three frequency bands of sound. Some high-rollers do not hesitate to put the most expensive audio equipment together, and there is a high probability that there will be a very ugly sound.
Strictly speaking, every piece of equipment is a semi-finished product. Our audio collocation, it is to take advantage of this, by understanding and using the strengths of the equipment to make up for the shortcomings of other equipment, and finally achieve sound in each frequency band has perfect expression and correct three-band relationship.
I used JBL's fifties speakers Hartsfield, playing Schnabel's Beethoven piano sonatas played in the thirties, the high-wind mono cartridge and vinyl records provided a thick midrange signal, and despite the recording from ninety years ago, the Hafei speaker still resonated very accurately through the 15-inch woofer and Z-model angle channel, and the intensity of each finger played by Schnabel ninety years ago is still clearly audible and felt. I can't help but be very surprised, this kind of piano performance without high-frequency overtones, compared with the sound of high-frequency overtones in later recordings but the piano body is faint, which is more like a real piano and real performance, which is closer to the so-called "high fidelity"?
This is really a difficult question to answer.