The spectrum of the musical signal. Part 5

The kick drum when you play will be a blow to the Squeaker. It is not dangerous even at high power.

And are there any musical instruments that are played only a Squeaker? We looked at the barrel and found. Here's a spectrogram of the ordinary, it is not academic tambourine.

Here, in any system, the entire burden will fall on the Squeaker, because below 5 kHz, the amplitude of the signal falls just rapidly. And fatal to RF emitters are usually just large signal levels at a relatively low (for stuff) frequencies near the resonance frequency. Experimenters note: percussion percussion strife.

This is the situation at the top. And the lower classes?

The lower classes do not want

The attentive reader (you, for example) noticed how interesting to have a relationship to the standard curve of spectral composition behalf of the German DIN standard. At lower frequencies the reality differs from the standard, such as the life from the literature. That is harder. AFC real musical activity stands proudly above the boring German standard. But not all the time, but only up to about 40 - 50 Hz. And below the amplitude of the fast Blendable, trying to hide below -20 dB. How is it, where rebellious spirit, where wild, impossible, sweet supersize, type 20 Hertz, or, Oh, 25? Yes is not present in their NORMAL music. Nope all. And this we now turn to prove.

Solo double bass: the bass is not exactly a "contra"...

The first proof that real music phonograms no serious level components with frequencies below 40 - 50Hz - already you have seen average schedule. But the statistics, in the sense of averaging - a case related to stock exchange speculation, so we will try to be more specific. How do you show a bass instrument recorded separately from the others that sounded downright on the infrasound? Or at least on the border of the audio range of 20 Hz? After all, the competition rules for car audio require uniform frequency response from 20 Hz. Step up, step down - trying to defeat.

Here we take the double bass. Look carefully at the range of frequencies produced by the game some talented black musician on the largest bass strings. Look and feel for all the efforts of black talent frequencies below 60 Hz - sparse. The maximum spectral density falls at 100 Hz, according to our classification - typical range midbass. The subwoofer in the performance of this solo almost on vacation.

Range of punch in the bass drum: have maximum amplitude at 40 Hz.

Not convinced? Well, right. The double bass is that there is a bass drum on which either sweaty, shirtless, labuha, or dressed in evening a couple of orchestra as hestnut, and...

... and receive the maximum amplitude of the spectrum at 40 Hz. And below it all falls still rapidly, and to around 20 Hz, so sacred to some, from the sound of the formidable bass instrument remain horns and legs.

Well what else can I show you? Want - famous Japanese Kodo drums, the largest of which weighs four pounds? Here the range of their sound, recorded to have lots of talks, the most that neither is competent in such matters company - Sheffield. From zero write.

The result of careful and thoughtful (well, we know you are not the first year) examination of the spectrogram: max - 60 Hz, border informative bass - 30 Hz. Everything below small pieces.

Even the huge Japanese Kodo drums beat mostly in the band of 40 - 60 Hz.

There is Chinese, where the same without them. They, too, during the Yellow Ancestor (thence the Tsar Pea) coined the reels. Then these reels recorded for their needs supercompany on super-high-end Burmester. The graphic on the left spectrum of all these Supes.

Cooley defeated samurai, substantial energy spectrum of the sound of their thundering percussion instrument extends to 30 Hz. But as it is no more (or no less).

Quite snitches, they do not justify the hopes. There are other contenders for bass laurels. Remember impressive passages on the keys of the Cathedral organ: who are they indifferent to, the fact, then, in the childhood vaccine made from bass...

For the rest, not vaccinated, range of classical performance of the Toccata in d minor, Bach, works universally recognized iconic as the music and sound (which is not the same thing, it's understandable).

Chinese version of bass drums. Already below, but those as you think.

Toccata in d minor Bach: sample deep bass records.

Cults that proved to be quite real in the sense of spectral composition. Playing the organ notes of really extends to the limits of audibility, although, admittedly, where their amplitude is not stunning. We completed this schedule standard curve range for the "old" scheme IEC. The limits of liability standard (50 Hz) is very similar, agree. But below 50 Hz the amplitude is in no hurry to fall, while remaining small, but noticeable to infrasonic frequencies.


  • The Magazine "Car Audio" No. 11 / 2000

Author: Andrew Elyutin; Publication:,


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