This article is excerpted from a part of Taiwan's famous sound engineer Liu Hansheng's "Audio Twenty", which tells the distribution and control of the volume of the high, medium and low frequency of the sound, which is worth reading.
This project is easy to understand, but it is also easy to produce misunderstandings in text communication. How do you say it? Everyone will say: The treble of the pair is too strong and the bass is too small. This is the volume distribution of the high, medium and low frequency bands. The problem is that if the bandwidth from 20Hz to 20KHz is divided into three segments, it will inevitably lead to "inaccurate" confusion. In the end, what is your bass point? How low is it? In order to make the description of the text more precise, it is necessary to subdivide the bandwidth of 20Hz-20kHz.
According to the US TAS and Stereophile's method is very simple, they subdivide the high, medium and low segments into three sub-segments, which is to become the "lower intermediate frequency, intermediate frequency, higher intermediate frequency" method. This division is like a twelve-average law, quite regular. However, when used in Chinese people, there are some minor translation problems, such as "lower intermediate frequency", which we call "middle frequency" or "low IF"? So high frequency? "High and low frequency"? For the Chinese, the division of foreigners may not work. So long ago I referred to the bandwidth of the instrument and the orchestra's name for the sound. The frequency of 20Hz-20KHz was divided into seven segments: extremely low frequency, low frequency, low frequency, medium frequency, medium frequency, high frequency, very high frequency. . The nouns of these seven paragraphs are in line with the customary names of ordinary Chinese people, and they are easy to remember and will not be confused.
　　 Extremely low frequency
This octave from 20Hz-40Hz is called the extreme low frequency. There are very few instruments in this band, and only instruments such as double bass, bass bassoon, toba, organ, and piano can reach such a low range. Since this extremely low frequency is not the most beautiful range of the instrument, the composers rarely write the notes so low. Unless the pop music is deliberately arranged with an electronic synthesizer, the extremely low frequency is of little use to the audio fans. Some people mistakenly believe that although the pitch of the instrument is not so low, the overtone can be as low as the pitch. In fact, this is not true, because the pitch of the instrument is the lowest sound of the sound, and the sound will only climb up twice, three times, four times, five times, etc., without the downward sound. It's like you tighten a string. The full-length vibration frequency of the string is the pitch, one-half, one-third, one-quarter, one-fifth. The vibration of the chord length is the overtone. The addition of pitch and overtone is the tone of the instrument. In other words, the violin and the flute will behave differently even if the pitch (pitch) is the same.
Low frequency
The frequency from 40Hz to 80Hz is called the low frequency. What instruments are there in this band? Drums, double bass, cello, bass bassoon, bassoon, bass reel, bass clarinet, Tuba, French, etc. This band is a major contributor to the foundation of a thick and low frequency. Usually, the average person mistakes this band for extreme low frequencies because it sounds very low. If the amount of this frequency band is too small, the feeling of richness and sputum must not be; and it will lead to the highlight of medium and high frequency and high frequency, which makes the sound lose balance and is not durable.
Middle and low frequency
From 80Hz to 160Hz, I call it the mid-low frequency. This band is the biggest headache for Taiwanese audio fans, because it is the culprit in the ears. Why is this band particularly prone to peaks? This is related to the length, width and height of the small room. In order to remove this annoying peak, most people have tried their best to absorb this band, so that the ears will not be blasted. Unfortunately, when your ears don't sound like a bang, the lower frequency and the upper midrange are probably recessed with the absorption of the mid-low frequency, making the sound thinner and less rich. Even more unfortunately, most people think that this situation is correct only because the peak disappears. This is one of the reasons why many people's homes are not rich enough. The instruments in this band include the instruments mentioned in the low band just now. Yes, the timpani and the bass are also added.
Intermediate frequency
The frequency between 160 Hz and 1280 Hz spanning three octaves (320 Hz, 640 Hz, 1280 Hz) is called the intermediate frequency. This band contains almost all instruments and vocals, so it is the most important frequency band. The biggest misunderstanding of the instrument's range is also here. For example, most of the violin's semi-range is in this frequency band, but most people mistake it for it; don't think that the soprano range is very high. In general, her highest range is only at the upper limit of the intermediate frequency.
From the above description, you must also understand how important this intermediate frequency is to the sound. As long as this frequency is sag, the performance of the sound is immediately thinner. Sometimes, this thinness is easily interpreted as "false cohesion." I believe that there are a lot of audio fans who are in the mid-frequency depression and don't know. The importance of this band can also be analyzed from the crossover point of the two-way horn. Generally, the crossover point of the two-tone horn is mostly around 2500 Hz or 3000 Hz, that is, 2500 Hz or more is responsible for the high-pitched unit, and below 2500 Hz is responsible for the middle and low volume unit. This 2500 Hz is about twice the 1280 Hz, that is, in order to fear that the mid-bass unit has too much crossover point distortion at the IF limit, the designers have increased the crossover point to twice the upper limit of the intermediate frequency. In one case, the most perfect intermediate frequency can be emitted by the mid-bass. If this is true, what does the tweeter use? If you have put your ear close to the tweeter, you will hear a "beep" sound, that is, most of the overtones. If there is no treble sound from the tweeter, using a single bass speaker to sing music, it must be dull. Of course, if it is a three-tone design speaker, most of this intermediate frequency will be included in the midrange.
Medium and high frequency
From 1280Hz to 2560Hz, it is called medium and high frequency. What kind of instrument is there in this band? The violin has about a quarter of the higher range, the upper end of the viola, the flute, the clarinet, the high range of the oboe, the lower half of the piccolo, the cymbal, the triangle and so on. Please note that the small speakers are not in this band. In fact, the high frequency is easy to identify, as long as the high range of the string group and the high range of the wood tube are medium and high frequency. Many people in this band will mistakenly think that it is high frequency, so please pay special attention.
high frequency
From the frequency range of 2560Hz-5120Hz, I call it high frequency. This frequency domain has very few opportunities for instrumental performance. Because most of the instruments except the upper limit of the violin, the piano, and the Piccolo high range, most of the instruments do not appear in this band. From the crossover point of the horn, we can find that all of the frequency domain appears in the tweeter. As I said before, when you put your ear close to the tweeter, what you hear is not the sound of the instrument, but a squeak. From the performance of the tweeter, it can be proved again that the tweeter alone emits a pitch of a musical instrument or a human voice, which is only a high-order overtone of the pitch.
Extremely high frequency
From the wide frequency range of 5120Hz-20000Hz, I call it very high frequency. You can learn from the fact that there are very few instruments at high frequencies, and you know that the extremely high frequencies contain the overtones of instruments and human voices. In general, the overtones of musical instruments are mostly the higher the energy, in other words, the high-pitched sounds are made sharply and can reproduce very fine sounds clearly. From here, there has been a problem that has plagued the manufacture of horns, that is, how to make the best of both worlds? What is "two things"? Have you ever thought about it, if a treble monomer reproduces all the subtle overtones clearly, it is desperate. Designed to drive the diaphragm with a small current, the high-energy high-frequency and intermediate-frequency frequencies that are also responsible for this high-pitched unit are likely to be constantly distorted because the energy in these two bands is much higher than that of the very high frequency. It’s too big. This is one of the reasons why many speakers on the market are very clear, but they are easy to flow.
Do you still remember the previous Spentdor SP-1 speaker? It is a three-way design, the three-way path? The mid-bass unit, the tweeter, and the super-high-sound unit. The super high-pitched unit is responsible for frequencies above 13,000 Hz. I remember that many people were "incomprehensible" at the time. Why does the SP-1 have a super-high-pitched unit, and the sound is so soft? It should be very sharp! Now I think you should understand it! SP- 1 The design point is to make the tweeter alone not to be distorted, but to reproduce extremely high frequencies. This is one of the reasons why SP-1 sounds comfortable and musical.
After understanding the segmentation method of the high, medium and low frequency bands, we will then discuss the "control power" beyond the sense of quantity. The sense of quantity is of course the amount of quantity, that is, what we say: higher treble, less bass. Control power usually refers to the control of "low frequency band and high frequency band". Some devices are loose at low frequencies and some are flexible. We will say that the latter has low frequency control. Some equipment can hold high frequencies, so that it won't get your ears uncomfortable. We say that it has good high frequency control. Please note that the amount of sense in each frequency band does not mean that the equipment is really good or bad. The combination of the amount of equipment is important. The quality of control can be said to be the superiority and inferiority of the equipment itself.
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