No matter in the era of functional phones or smart phones, music phones have been positioned by many manufacturers to attract some users who like listening to music. Recently Published Find 5 As always, it inherits the gene of OPPO music mobile phone and adopts the new Dirac HD ® And Dolby Mobile Sound 3.0 technology. Dirac HD、 Dolby sound effect... these words can often be used by businesses as promotional selling points. I believe everyone is familiar with these words, but do you really understand them?

Let's talk briefly first Dolby Sound 。 Dolby Pro Logic is a surround sound system developed by Dolby. It synthesizes the four channel stereo into two channels through a specific encoding method during recording, that is, the four signals of the original left channel (L), right channel (R), center channel (C), and surround channel (S) are encoded and synthesized into LT RT composite dual channel signal. During playback, the encoded dual channel composite signals LT and RT are restored to four independent signals that do not interfere with each other, namely, left, right, center and surround, through the decoder. After amplification, they are respectively input into the left speaker, right speaker, center speaker and surround speaker. Because of this feature, Dolby is often used in cinemas and home theaters, and it only improves stereo sound, not sound quality itself.

Dirac HD Sound means that the sound quality has been improved on the sound source.

Dirac HD Sound is an advanced patented technology developed by Dirac Research AB in Sweden. It can compensate the loudspeaker system through digital processing. By correcting the transient response and frequency amplitude response of the sound system, it can make earphones or speakers achieve high fidelity performance.

The first is to correct the transient response of the sound system: due to the nonlinear characteristics of the speaker system itself, the transient response will change. The importance of the transient response of a loudspeaker system is one of the key factors of the fidelity of a system.

The following figure compares the amplitude changes in response time and attenuation time when a loudspeaker system plays a transient response signal before and after Dirac HD Sound processing:

Compared with the test results, for the same transient signal, it takes a long time for the original system to stop from receiving the transient signal to playing. If another sound signal collides with the previous transient signal again, it is clear that the transient signals at two different time points are mixed together, This results in the loss of fidelity during sound playback. After Dirac processing, the signal playback can be completed instantly and the unit can stop in time. The compensation technology of Dirac HD Sound can well improve the above problems, and the sound quality can be significantly improved by compensating the transient response characteristics. In fact, to put it bluntly, it is to remove some impurities and filter the sound to make it clean and pure, so as to make the sound quality better.

Secondly, the frequency amplitude response of the sound is modified: the frequency amplitude response is related to the playing volume ratio of various music elements, and is also an important factor of system fidelity. We often say that the treble is harsh, the bass is booming, and there are too many mid-range tones. In fact, the horn's frequency amplitude response is poor, and it does not accurately restore the volume of the original signal. Dirac HD Sound technology adopts a unique hybrid phase technology. Compared with traditional equalization processing, Dirac HD Sound technology improves the frequency amplitude response of the system more reasonably and effectively, and corrects the frequency amplitude response characteristics of the horn with near perfect high accuracy. Therefore, we can hear the original appearance of the sound.

From the above figure, we can see that the speaker frequency amplitude response corrected by Dirac can accurately match the target curve, thus accurately restoring the true volume of the original music signal. The upper part of the figure above is the measured frequency amplitude response of the speaker before optimization, and the lower part is the measured response after optimization by Dirac HD Sound technology. The black part is the target curve we hope to achieve.

OPPO began to use Dirac HD Sound on its series of mobile phones in 2012. Ken Kreisel, founder of M&K, a professional monitor box manufacturer, said when commenting on the voice of OPPO mobile phone, "When using the new OPPO mobile phone and earplugs to listen to music with Dirac HD Sound, the sound quality is improved so significantly that I feel almost as if I am in a recording studio equipped with my new generation of monitor speakers..." Is it really so magical Love to play computer games The team will present OPPO Find 5 in detail as soon as it receives it.

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