TrebleHunter: Truy tìm tiếng treble hay!

dạ em dang xài củ loa toàn dải cũa nga xô hiệu OMO BÁC Ạ liên hệ bác VIAGRALESS bằng cách nào hả bác? thân

 

dạ em dang xài củ loa toàn dải cũa nga xô hiệu OMO BÁC Ạ liên hệ bác VIAGRALESS bằng cách nào hả bác? thân[/quote]

Bác pm thử xem !

Thân

 

Bác pm thử xem !

Thân[/quote]
em hỏng biết pm ở chổ nào bác ạ, bác giúp em luôn được ko a em cám ơn bác nhiều, em dốt vụ này lắm bác ơi. thanks

 

Chào các bác!
Tai chúng ta chỉ nghe được giải tần từ 20Hz-20KHz thôi. Ngoài dải đó thì chúng ta chịu, ko nghe thấy gì. Còn các hãng họ sản xuất loa tép có dải tần trên 20KHz vì theo nghiên cứu của họ dải tần này dù tai ko nghe thấy nhưng lại ảnh hưởng nhiều đến chất tiếng trong giải mà ta nghe thấy được. Theo em, tiếng tép hay thì nghe phải tự nhiên, dễ chịu, mềm mại và tách bạch.
Thân!

 

Bác DUONG nói chí phở vì theo em biết thì hài âm bổ phụ cho âm thanh rất nhiều. Nên một số kỹ sư trên thế giới biết điều này trước, rồi đến các thầy nhà ta sau. Nên họ làm một số AMP có chỉnh đôi chút trông mạch để gia tăng hài âm để người nghe ngộ nhận nhưng thực ra là làm méo tiềng-> không thật tiếng so với đĩa gốc. Còn xin mạn bàn ngoài lề chút: với máy móc chả có cái gọi là âm thanh trung thực đâu. :roll: :roll: :mrgreen:

 

Con người mà nghe được trên 20khz như dơi hay chó thì nghe được nhiều thứ Bác ha ... có rất nhiều nhạc cụ thể hiện trên 20khz lém lém Bác các nhà đo đạt họ dùng máy đo được tới đâu 102,4khz lận Bác hình ảnh tần số mà họ đo đạt được các nhạc cụ thể hiện trên 20khz, các bác xem hình nha và bài viết để nguyên ....Bài viết rất dài Em chỉ ngắt đoạn này các bác tham khảo chơi cho vui hen ....

At least one member of each instrument family (strings, woodwinds, brass and percussion) produces energy to 40 kHz or above, and the spectra of some instruments reach this work's measurement limit of 102.4 kHz. Harmonics of muted trumpet extend to 80 kHz; violin and oboe, to above 40 kHz; and a cymbal crash was still strong at 100 kHz. In these particular examples, the proportion of energy above 20 kHz is, for the muted trumpet, 2 percent; violin, 0.04 percent; oboe, 0.01 percent; and cymbals, 40 percent. Instruments surveyed are trumpet with Harmon ("wah-wah") and straight mutes; French horn muted, unmuted and bell up; violin sul ponticello and double-stopped; oboe; claves; triangle; a drum rimshot; crash cymbals; piano; jangling keys; and sibilant speech. A discussion of the significance of these results describes others' work on perception of air- and bone-conducted ultrasound; and points out that even if ultrasound be taken as having no effect on perception of live sound, yet its presence may still pose a problem to the audio equipment designer and recording engineer.
I. Introduction
Each musical instrument family — strings, winds, brass and percussion — has at least one member which produces energy to 40 kHz or above. Some of the spectra reach this work's measurement limit of 102.4 kHz.
Harmonics of French horn can extend to above 90 kHz; trumpet, to above 80; violin and oboe, to above 40; and a cymbal crash shows no sign of running out of energy at 100 kHz. Also shown in this paper are samples from sibilant speech, claves, a drum rimshot, triangle, jangling keys, and piano.
The proportion of energy above 20 kilohertz is low for most instruments; but for one trumpet sample it is 2%; for another, 0.5%; for claves, 3.8%; for a speech sibilant, 1.7%; and for the cymbal crash, 40%. The cymbal's energy shows no sign of stopping at the measurement limit, so its percentage may be much higher.
The spectra in this paper were found by recording each instrument's sound into a spectrum analyzer, then "prospecting" moment by moment through the recordings. Two instruments (clarinet and vibraphone) showed no ultrasonics, and so are absent here. Other instruments' sounds extended high up though at low energy. A few combined ultrasonic extension with power.
The mere existence of this energy is the point of this paper, and most of the discussion just explains why I think that the spectra are correct, within the limits described below. At the end, however, I cite others' work on perception of air- and bone-conducted ultrasound, and offer a few remarks on the possible relevance of our spectra to human perception and music recording.
II. Explanation of trumpet spectra in Figures 1(a) & 1(b)
The upper trace in Figure 1(a) shows the spectrum of a concert B-flat played on a trumpet with a Harmon ("wah-wah") mute, as captured by an Aco/Pacific quarter-inch microphone four feet away and analyzed with a Hewlett-Packard model 3567A FFT spectrum analyzer. This and all other instruments were played in normal concert fashion. (For details of instruments and players, see Appendix A.)
The lower trace shows the background with the trumpet silent; this is dominated by the microphone's "self-noise," as shown in section VIII, below. Of course this background is present when the trumpet plays; and that is why the upper trace is identified as "Trumpet + Background."
Are the trumpet peaks actually harmonics? To find out, we'd like to place markers at harmonic frequencies. To be easily readable, though, such a graph would have to be huge, so Figure 1(b) provides excerpts from it.
The first excerpt shows the spectrum up to 8 kHz; the second, from 15 to 32 kHz; the third, from 38 to 53 kHz. Note the 100th harmonic at 46,560 Hz and the 108th at 50,263 Hz. (The vertical scale has been adjusted separately in each excerpt to make it easier to judge the presence or absence of harmonics. Figure 1(a) shows the overall relationships of level.) It is clear that the peaks are indeed harmonics (and equally clear in the omitted portions of the frequency spectrum, for this and the other spectra).
The fourth excerpt shows that by 55 kHz, the harmonics are vanishing. Note that, as seen in Figure 1(a), the trumpet is still 12 to 15 dB above the background at this frequency; so the energy seen at 55 kHz, though non-harmonic, is still trumpet sound. To be conservative, however, I don't claim this portion of the spectrum as part of the sound; and Table I says only that harmonics are visible to "above 50 kHz." Similarly, where the last column in Table I shows that 0.5% of the total energy is above 20 kHz; this is calculated only to the 50 kHz limit given for the harmonics.
In Figures 2(b) through 9(b), as in this one, the last excerpt will show the region where visible harmonics vanish.
III. More trumpet, horn, violin, and oboe
In the same way as just described for Figure 1, Figures 2 through 9 give information about other instruments whose sound has harmonics.
Skipping Figure 1(c) for the moment, in Figure 2 we see another sample of trumpet with Harmon mute, 20 dB lower in level than the sample in Figure 1, yet with harmonics extending higher, and with a higher percentage of its total energy in the harmonics. (See Table I.) Figure 3 shows trumpet with straight mute. Here the harmonics extend higher yet, to above 85 kHz.
Figures 4, 5, and 6 give three examples of French horn, played respectively "bell up," with mute, and in normal fashion. One hundred or more harmonics are visible in each!
Figure 7 shows a violin "double-stop", that is, two notes played simultaneously. Since each note produces its own harmonic series, Figure 7(b) uses markers of two different shapes to show the two harmonic series.
Figure 8 shows a single violin note played sul ponticello, that is, with the bow very close to the bridge. This gives a distinctive squeaky-scratchy sound which composers sometimes specify, as for example Beethoven in the C-sharp Minor string quarter, Opus 131. Even in this mezzo-piano (medium-soft) note, harmonics are still visible past 40 kHz. (Due to absence of mind, I took no sample of normal violin sound playing a single note normally.)
Figure 9 shows an oboe note. It is striking how the harmonics suddenly drop in level after the 40th at 43 kHz.
Not shown are any clarinet or vibraphone samples, because, as mentioned above, I could find no harmonic activity above 20 kHz anywhere in several samples of each, despite the closest "prospecting" with spectrum analyzer. These were the only instruments of the group that did not show such activity.

 

ngày xưa Em cứ nghĩ âm thanh nhạc cụ nó chỉ lên như hình này thôi nhưng thật ra thì nó khác nhiều ....

 

Rất nhiều nhạc cụ có âm thanh vượt 20khz, hình đo được thế này ....

 

giọng ca cũng véo von không kém....

 

violin....