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MIDI and digital sound: pros and cons

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MIDI and digital sound: pros and cons

Digital Audio

The WAVE format is one of many, but it is far from the only format for recording digital audio.

Digital Audio

Unlike MIDI data, digital audio data is actually sound recorded in thousands of units called samples. Digital data represents the amplitude (or volume) of a sound at discrete moments. The sound of digital data is independent of the playback device and therefore always sounds the same. But you have to pay for this with large volumes of sound files.

MIDI data is to digital data what vector graphics are to bitmaps. In other words, MIDI data depends on the audio playback devices and digital data is independent. Just as the appearance of vector graphics depends on the printer or monitor screen, the sound of MIDI files depends on the MIDI device to play these files. Similarly, a melody played on a concert piano will sound different from a normal piano. Digital data, on the other hand, is identical and independent of the reproduction system. The MIDI standard is similar in this respect to the PostScript standard and allows you to control instruments in understandable language.

Compared to digital sound, MIDI has the following advantages:

MIDI files take up less memory and the size of these files does not affect sound quality. On average, MIDI files are 200 to 1000 times smaller than digital files and therefore take up a small amount of RAM, disk space and do not require large CPU resources.

In some cases, MIDI files sound better than digital audio files. In this case, the sound source of the MIDI files must be of high quality.

You can change the length of MIDI files by changing the tempo of the sound, while maintaining the quality and volume of the sound. MIDI data can be easily edited, even at the single note level. You can manipulate small segments of a MIDI song (with millisecond precision), which is not possible with digital audio.

The main disadvantage of a MIDI file comes from its merits. Since MIDI data is not sound itself, playback will be as accurate as the device for playing the MIDI data is identical to the device used to create the original file. Even the sound of a MIDI instrument according to the General MIDI standard depends on the electronic playback device and the method used. MIDI sound is not used for voice playback.

The main advantage of digital audio over MIDI sound is that the reproduction quality of digital sound is always constant, and here MIDI sound is inferior to digital sound. There are two reasons why you should work with digital audio:

A wider selection of programs and systems that support working with digital sound.

The preparation and creation of digital sound elements does not require knowledge of music theory, which cannot be said for MIDI data.

Sound tips
Voice recording from microphone
Any book devoted to multimedia necessarily contains a section on microphone sound recording. In addition, the Sound Recorder (Phonograph) program, which is included in the standard Windows distribution, is usually used for this. Working with it is described in detail in the attached help file. It is easy to use and we will not dwell on it in detail.

The microphones come in condenser and dynamic microphones. Capacitors are more expensive, they give better sound, but your connection must be compatible with a sound card. And the vast majority of sound cards are designed for dynamic microphones.

Another important characteristic of a microphone is its directivity. The microphones are omni-directional (they have the same sensitivity to sound in all directions), unidirectional (they have the highest sensitivity to sound coming from the front), and bi-directional (more sensitive to sound coming from the front and rear). A unidirectional microphone is usually the best option, as it eliminates background noise. But it is more expensive than omni-directional microphones and is more sensitive to choppy breath sounds.

Be sure to pay attention to the impedance (impedance) of the microphone. The optimal value is around 600 ohms.

Therefore, we recommend a 600 ohm dynamic omni-directional microphone.

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Differences between analog and digital audio

Differences between analog and digital audio

Analog vs Digital

Sound information. Sound is a wave that travels through air, water, or other medium with a continuously changing intensity and frequency.

Digital vs. Analog

A person perceives sound waves (air vibrations) with the help of hearing in the form of sound of varying volume and pitch. The greater the intensity of the sound wave, the louder the sound, the higher the frequency of the wave, the higher the pitch of the sound (Fig. 1.1).

Dependence of the volume and pitch of the sound on the intensity and frequency of the sound wave.

The human ear perceives sound at a frequency of 20 vibrations per second (low sound) to 20,000 vibrations per second (high sound).

A person can perceive sound in a wide range of intensities, in which the maximum intensity is 1014 times greater than the minimum (one hundred thousand billion times). A special unit of “decibels” (dbl) is used to measure the volume of sound (Table 5.1). Decreasing or increasing the sound volume by 10 dB corresponds to a decrease or increase in sound intensity by 10 times.

Provisional discretization sound. In order for a computer to process sound, a continuous audio signal must be converted to a discrete digital form using time sampling. A continuous sound wave is divided into separate small time sections, for each section a certain value of sound intensity is set.

Therefore, the continuous dependence of the loudness of the sound at time A (t) is replaced by a discrete sequence of loudness levels. On the graph, this appears to replace a smooth curve with a sequence of “steps” (Fig. 1.2).

Sync Audio Sampling

Sampling frequency. A microphone connected to the sound card is used to record analog sound and convert it to digital format. The quality of the digital sound obtained depends on the number of measurements of the sound volume level per unit of time, that is, the sampling frequency. The more measurements that are made in 1 second (the higher the sampling frequency), the more accurately the “ladder” of the digital audio signal repeats the curve of the dialogue signal.

The audio sample rate is the number of sound volume measurements in one second.

The audio sample rate can vary between 8000 and 48000 sound volume measurements per second.

Audio encoding depth. Each “step” is assigned a specific value for the sound volume level. Loudness levels of sound can be viewed as a set of possible states N, for which a certain amount of information I is required, which is called audio coding depth.

Audio encoding depth is the amount of information required to encode the discrete volume levels of digital audio.

If the encoding depth is known, then the number of digital audio loudness levels can be calculated using the formula N = 2I. Let the audio encoding depth be 16 bit, then the number of sound volume levels is:

N = 2I = 216 = 65536.

During the encoding process, each sound volume level is assigned its own 16-bit binary code, the lowest sound level will correspond to the code 0000000000000000 and the highest – 1111111111111111.

The quality of digitized sound. The higher the sampling frequency and depth of the sound, the better the sound of the digitized sound. The lowest quality of digitized sound, corresponding to the quality of telephone communication, is obtained at a sampling rate of 8000 times per second, a sampling rate of 8 bits, and by recording an audio track (“mono” mode). The highest quality of digitized sound, corresponding to the quality of an audio CD, is achieved with a sampling rate of 48,000 times per second, a sampling rate of 16 bits and the recording of two audio tracks (stereo mode) .

It should be remembered that the higher the quality of the digital sound, the greater the volume of information in the audio file. You can estimate the volume of information in a digital stereo sound file with a duration of 1 second with an average sound quality (16 bits, 24,000 measurements per second). To do this, the encoding depth must be multiplied by the number of measurements in 1 second and multiplied by 2 (stereo sound):

16 bits × 24,000 × 2 = 768,000 bits = 96,000 bytes = 93.75 KB.

Sound editors. Sound editors allow you not only to record and play sound, but also to edit it. Digitized sound is presented in sound editors visually, so copying, moving, and deleting parts of the audio track can be easily performed with the mouse. Also, you can layer tracks

Differences between analog and digital sound

Which is better, analog or digital sound?
Is there really a difference?
Do you need a very expensive audio equipment to notice the differences?
And does it really matter?

Before entering the discussion, we should take a quick look at what makes a sound digital or analog. It all has to do with how a sound is recorded. An analog sound recording copy is a continuous electronic signal.

Currently, advances in conversion methods to transform analog to digital have improved the quality of digital recordings. Some people say that there is no distinction between digital and analog mode. Others disagree – sometimes with passion. Music lovers – people who want the highest possible quality in sound systems – insist that analog systems provide better sound.

What are the real differences in the real sound of analog and digital recordings?

DIGITAL SOUND HISTORY

BEFORE THE 1970s, MUSICIANS RECORDED WITH ANALOG RECORDING EQUIPMENT.

Microphones that record the sound and generate an analog wave that other devices could transfer directly to the appropriate media (usually magnetic tape). Assuming that the musician uses reliable equipment, the recorded sound was a faithful representation of the original sound.

With digital recording, codecs convert analog waves into digital signals. There are many different types of equipment that can convert from analog to digital. Some audio studios record analogically on an original master tape, and then transfer the sound to a digital format. Others use special equipment to record directly in digital.

The first digital recordings sacrificed fidelity, or sound quality, in favor of reliability. One of the drawbacks of an analog format is that analog media tend to wear out quickly. Vinyl records can be deformed or scratched, and this can dramatically affect the sound quality. The magnetic tape eventually wears out and is vulnerable to magnets, which can erase or destroy the information stored on the tape. Digital media such as compact discs can reproduce sound indefinitely, and are more durable.

ANALOG VS DIGITAL

Some music lovers believe that digital recordings fall short when it comes to reproducing sound accurately. They use intricate language, and jargon, to describe the capabilities or deficiencies of an audio system. Most of his criticisms deal with the frequency of sound.

Humans can hear sounds ranging from 20 hertz (Hz) to 20 kilohertz (kHz). The frequency of a sound wave corresponds to our perception of the height of a sound. The higher the frequency, the greater the tone we hear.

Sound lovers describe the sound quality of an audio system with respect to different frequencies by using terms such as full, warm and airy. A full or warm sound comes from a system that reproduces low frequencies well. An airy sound means that the music played gives the listener the impression that the instruments are in a spacious environment and usually refers to the sounds in the high frequency range.

Some music lovers say vinyl albums perform better at lower frequencies, which means they provide a warm sound. They argue that compact discs are not as accurate in the reproduction of sounds in this range. Others insist that there is no detectable difference between a well-produced digital file and a good-looking vinyl record.

If the artist uses an analog format to create the original recording, then an analog copy is the best. That is because there would be no need to convert the sound from analog to digital. The copy must be an exact representation of the original track. But if the artist uses digital recording, then it would be better to buy the album on CD.

The perception of musical quality is subjective. Two people who listen to the same music, with the same equipment, may have different opinions regarding the quality of the recording.

ANALOG AND DIGITAL SIGNS

Sound is, of course, an analog signal. An analog signal is continuous, which means there are no breaks or interruptions. The digital signals are not continuous. Specific values are used to represent the information. In the case of sound, a sound wave is represented as a series of values that represent tone and volume over the length of the recording.

Some argue that analog recording methods are better at capturing a faithful sound image. Digital recordings can lose subtle nuances. But as digital recording processes improve, digital devices can use higher speeds with greater precision. Although the signal is not yet continuous, the high frequency can create a sound similar to the original source.

Another advantage of digital media over analog.

You can make as many copies of the original sound file as you want, without harming it. Over time, even a master analog recording will not sound as good as the original sound. But nothing corrupts a digital file, which will remain the same, no matter how much time has passed or the number of copies made.

ANALOGUE AND DIGITAL SOUND TODAY

Today, the technology in the audio recording industry is so advanced that many sound engineers will tell you that there is no detectable difference between analog and digital recordings. Even if you were to use the best sound equipment, you will not be able to identify one medium or another just by listening to the sound. Many music lovers agree and affirm that the analog format remains supreme.