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25.09.2019

Presentation on computer science on the topic “Multimedia. Analog and digital audio. Technical multimedia tools" download for free. Multimedia technologies

Sound cards in multimediaSOUND CARDS IN MULTIMEDIA
Today, sound cards are a whole class of devices, many of which serve much higher
purposes than simply outputting MP3 files to five-dollar speakers. They become the centers of the home
cinemas, Hi-Fi systems, home and professional studios.
By the way, the boards were called boards because they were a printed circuit board,
inserted into an ISA or PCI slot. Today, sound cards are also connected via USB, FireWire, PCMCIA.
Also, the tasks and capabilities depend on the device class,
that will be entrusted to the devices when working as a component in any version of media content.
3

Sound card device

SOUND BOARD DEVICE
For this purpose, the board has an ADC and a DAC - analog-to-digital
and digital-to-analog converters, between which
The digital flow control logic is placed.
The sound arriving at the ADC is in analog form - in the form
continuously changing electrical signal – subjected to
it involves sampling and quantization. Discretization splits
continuous signal to a sequence of its instantaneous
values ​​- samples following with a higher frequency,
and quantization encodes the level of each sample as an integer in the range 0..255 (8-bit digitization)
or 0..65535 (16-bit digitization). As a result, a stream of numbers is formed, the magnitude of which describes
law of change in the original signal. This stream passes through the control circuit and can be read
from there directly by the processor through the card registers, but most often automatic
transfer directly to memory (direct memory access - DMA), which only requires the processor to
4
configure the starting address and transfer parameters, and the system DMA controller and
card digital path control system.

Built-in sound cards

BUILT-IN SOUND CARDS
Where are they built in? In motherboards. Right on "mother"
solder inputs/outputs and codecs, and the entire computing
The processing is taken over by the central processor. Similar
sound solution is almost free, that's why for
unpretentious users are more than acceptable –
despite the terrible sound quality.
Latest motherboards have built-in cards
provide a 5.1 output - that is, theoretically, even with
with the help of such a device you can build a “home
cinema" by connecting a set of 5.1 speakers. but the sound quality
there will be very little.
Also, additional effects cannot be connected to such boards.
and equipment.
Price range: $0-4 (in the form of additional payment for a motherboard with
audio).
5

Types of sound cards

TYPES OF SOUND CARDS
There are two types of sound cards, namely:
Built-in and internal boards, such as are found in laptops and motherboards. They are not
give decent sound quality, and we won’t touch on them too much
The boards are external, they have a variety of form factors,
as well as methods of connection and switching between each other.
They are best suited for most tasks,
therefore we will consider them.
6

External sound cards

EXTERNAL SOUND CARDS
This type of board is more common in areas where
sufficiently high-quality devices for working with sound.
Because they have more functionality and the ability
connecting additional equipment such as Preamp, compressors and equalizers.
I would like to note a large number of features, such as
inputs and outputs, as well as switching options. Opportunity
connect controllers and MIDI keyboards, and the presence of direct
monitoring recording channels, as well as a large number of inputs
and exits, and the ability to insist everything, for a certain
tasks.
7

Multimedia sound cards

MULTIMEDIA SOUND CARDS
This is the most ancient category of boards: they were the ones who appeared first and made
computer is a means of playing and recording music. These cards, unlike
built-in, have their own sound processor, which deals with
sound processing, calculation of three-dimensional sound effects used in games,
mixing audio streams, etc.,
Several years ago, the multimedia board market was
very intense, there were battles between manufacturers. The most
prominent competitors were Aureal and Creative. Maps of these
companies used different algorithms for working with 3D sound - each had its own fans. With coming
motherboards with built-in audio conflicts
resolved themselves: all manufacturers of cheap
sound cards are gone. And there are few manufacturers.
8
Price range: $15-80.

Semi-professional sound cards

SEMI-PROFESSIONAL SOUND CARDS
As a rule, they are produced by manufacturers of professional equipment, focusing not on
musicians, but for lovers of good sound. In other words, cards for audio files.
They differ from multimedia boards in that they have better components, but not yet
record sound very well, although I can work with 7.1 sound, and with fairly good sound
files
But the recorded sound from such boards is extremely low
quality level, which is why they are mainly used
in inexpensive workstations, or home PCs.
9
Price range: $80-200.

Professional sound cards

PROFESSIONAL SOUND CARDS
These cards are designed for professional musicians, arrangers,
sound engineers. Everyone involved in the production and recording of any sound
accompaniment. suited to the task – and features: highest quality
sound playback and recording, minimum distortion, maximum opportunities for
working with professional software and connecting professional equipment.
Inputs/outputs instead of the standard 3.5 mm jack are made using 6.3 mm jack, or in the form
XLR connectors brought out using special interface cables. Many
cards have external blocks where all connectors are located for convenience
connections. These cards are designed to connect professional studio
acoustic monitors, mixing consoles, preamplifiers, etc.
These boards are convenient for connecting a large number of microphones at once
and monitors, as well as speakers on stages and in large halls. This is the class
devices are suitable for organizing video conferencing, recording and outputting voice
hall, for performances, for example for students.
10
Price range: $200-$...

Using sound cards

USING SOUND CARDS
You need to understand that different sound cards, as well as different power
video adapters are needed in different conditions and for different tasks.
If you need to play a video with sound for a small class of students,
then a laptop, a fairly large monitor, or a projector and
built-in sound card.
At the same time, to provide sound and video at the teachers’ congress, I will
deliver lectures for a large hall, using multiple monitors,
microphones and speakers, you will need more powerful and productive
sound and video boards.
Therefore, we will consider three options in which the following tasks will occur:
1. Screening in a small audience, video with sound.
2. Show photographs with one speaker, while doing this in
small hall.
3. And a congress of Teachers, to give lectures and discuss the issue with
students, in a large classroom, using multiple microphones
and speakers.
11

The concept of "multimedia"

THE CONCEPT OF “MULTIMEDIA”
Before we begin to solve the assigned problems, we will understand what exactly multimedia is and what role
takes sound.
The term "multimedia" is a Latinism that has penetrated from English-language sources into various languages
almost in the original transcription. It comes from the combination of the Latin words “multum” (many)
and “media, medium” (focus, means, method). Thus, literally “multimedia” means “many
environment."
The concept of “multimedia” is used in various fields of human activity. In the computer field this is
website development, hypertext systems, computer graphics, computer animation, etc. In the dictionary
“Basic concepts and definitions of applied cybernetics”, multimedia means interaction
visual and audio effects controlled by interactive software. Usually this
means a combination of text, sound and graphics in one electronic resource, and recently more and more often -
animations and videos.
Understanding this, it turns out that sound is only part of it all, and almost always plays a supporting role, also
there are options where sound works to complement the video series, and give a fairly large amount
additional information.
The difference in the clarity and correctness of sound reproduction depends both on the quality of it and on the device
on which it is played, so the same file will sound slightly different on different
devices.
12


Task: Screening in a small audience, video with
sound.
For this procedure you will not need much
a lot of equipment, because the task is quite
is simple and does not require more than
three devices. To display the video you will need
laptop, projector or large enough
monitor and small stereo speakers, with
sufficient output power.
In this situation, nothing is required for sound
except playback, since the sound is already
ready and does not require intervention, or
corrections.
13

Options for using sound in multimedia

OPTIONS FOR USING SOUND IN MULTIMEDIA
Task: Showing photographs, with one speaker, at
doing this in a small room.
To complete this task, you need something slightly different.
equipment, since one will be used
dynamic microphone, a pair of “big” pegs, also
You can play audio from the device you are using.
You will need not only a PC, a projector and speakers, but also
mixing console, preamplifier, if microphone
wireless, then only the base, which is usually included in the kit.
In this case, it is possible to use an equalizer,
since the frequency response of dynamic microphones may be
somewhat uneven, or distorted due to use
speakers may require the use of it.
14

Options for using sound in multimedia

OPTIONS FOR USING SOUND IN MULTIMEDIA
Task: Congress of Teachers, for reading
lectures, and discussion of the issue with students, in
large audience, using
several microphones and speakers.
To solve the problem, you will need enough
complex equipment, because for several
microphones need a mixer to set up
volume of each microphone. Also good
the choice will be a monitor controller,
because if the area is large enough,
then there may be too few pairs.
From additional, can be used
mixer, or even a compressor.
It is also possible to use USB interfaces,
to get a better sound.
15

Record sound to a multimedia file

RECORDING SOUND TO A MULTIMEDIA FILE
With the help of sound cards, you can both record sound and
Here you need to know the following:
For recording you will need an ADC (analog-to-digital
converter), almost every board has one, but
minimum quality for normal recording
is 44.1 khz, and 16 bits deep.
True, similar and even higher ones have almost
all boards, so the main indicator becomes
price. At about RUB 5,000, boards that can
Record the sound if you have a good microphone.
The simplest programs are audacity, and
programs built into Windows, Higher
level is Adobe audition, and Pro tools.
16

Using multimedia at home

USING MULTIMEDIA AT HOME
For personal use and watching videos,
listening to music and basic work with sound,
the sound card built into the
motherboard, since a device is rarely needed
capable of playing and recording in 192 khz quality,
and 24-bit depth. Preamps and similar
additional equipment is not needed in this case,
why has already been mentioned above.
It is important to understand that there can be different types
microphones and speakers, which may require
certain equipment for connection to audio
map
17

Conclusion

CONCLUSION
Sound cards are often used in multimedia, and at the moment they are needed in all devices, from
computer to phone.
Sound cards have a wide variety of sizes, the presence or absence of additional effects, different
connection and switching standards.
Over the past twenty years, their use has given every person on earth, at any time, the opportunity to
moment in time, listen to a file saved on his device, or on the Internet, with almost any
quality and any length.
Using different chains can give different options for the final sound, which can be useful when
different assigned tasks.

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    • Multimedia.

    Multimedia is a technology that combines information (data), sound, animation and graphics. In addition, multimedia is a means of exchanging information between a computer and the external environment.

    The word multimedia means many carriers. Multimedia product- interactive computer development, which may include musical and speech accompaniment, video clips, animation, graphics and slides, databases, text, etc.

    Multimedia products are divided on encyclopedias, educational and developmental programs, games and programs for children, advertising programs and presentations. Multimedia has two sides: hardware and software.

    Hardware side of multimedia can be represented both by standard means - video adapters, monitors, disk drives, hard drives, and by special means - sound cards, CD-ROM drives and sound speakers.

    Software side without hardware it makes no sense. Software tools are divided into purelyapplied Andspecialized.

    Applied- These are Windows applications themselves that present information to the user in one form or another.

    Software support for multimedia is contained in Windows, for example, Universal Player is a media player designed for playing audio and video recordings, cartoons and videos. Files containing video images and sound have extensions *.avi, *.mov, *.mpg. A special phonograph - Sound Recorder, is designed for recording and playing back sound, as well as for editing sound files.

    Sound files have extensions *.wav, *.mid, *.mod, *.voc, *.fli.

    Specialized- these are tools for creating multimedia applications - multimedia projects (for example, a program for creating multimedia presentations MicroSoft Power Point). This includes graphic editors, video editors (for example, Adobe Premier), tools for creating and editing audio information, etc.

    Multimedia tools allow you to enter information into a computer from a microphone, tape recorder, CD player, video camera, VCR, etc. A standard 5.25" CD-ROM laser disk has a capacity of up to 650 MB. It only works in read mode.

    Multimedia, as an independent direction in computer peripherals, arose in the early 90s in America. Then the first software products began to appear on CDs. In 1990, only 10 multimedia programs were published on CD, but today there are thousands of times more.

    With the help of multimedia, children's fairy tales come to life, talking programs for teaching foreign languages, reference books and encyclopedias with fragments of video and sound clips are created.

    The very names of the programs speak about this: “Your Family Doctor”, “Playing with the English Language”, “In the Ocean”, “Hermitage”, “Bible”, “Art”. All this becomes possible thanks to multimedia technology and CD-ROM drives on a personal computer. A multimedia computer must include: A system unit with a minimum 386 SX processor, a Super VGA monitor (with a video card of 512 kilobytes or higher), RAM of 4 megabytes or higher, a Hard Drive, a Sound card, a CD-ROM drive, an acoustic system (speakers, stereo headphones).

    Sound Cards

    The presence of a CD-ROM drive only allows you to listen to audio CDs. A sound card is required to obtain professional quality audio, create and record sounds, synthesize complex audio effects, mix audio information from several sources, independently include audio in multimedia presentations, supplement documents with voice annotations, etc.

    A sound card (or Sound Blaster) is usually installed in the form of an electronic board into a connector on the computer's motherboard.

    The history of the development of sound cards begins with the release of the very first models of IBM computers. Initially, computers were equipped only with a PC Speaker, which was not designed to reproduce normal sound.

    At that time, no one even thought about any multimedia programs, and computer games were practically the only use for good sound. The first sound card for the IBM PC was made by TANDY. The sound of this card was approximately similar to the sound of cards in gaming computers (3 musical voices). Other companies began to produce sound cards. The most famous of them are Adlib, Creative and Roland. Adlib sound cards are one of the simplest and cheapest sound cards in use today. Their sound is based, like most common cards, on frequency modulation (FM).

    The card contains 11 FM voices and can play music quite well. But she can’t handle digital (or digitized) sound. Cards of this type are monophonic, but they often use the pseudo-stereo principle. Today, cards that only support the Adlib standard are obsolete. Sound cards from Creative Labs have become the standard for modern multimedia systems. An important difference between these cards is the ability to reproduce digital sound, that is, almost everything that can be heard. The quality of playback depends on two important parameters - bit depth and sampling frequency (this is the data update rate). The bit depth of the cards is usually 8 and 16 bits, and the sampling frequency is 4 to 44.1 kHz.

    Digital sound cards are reproduced and recorded thanks to digital-to-analog and analog-to-digital converters (DAC and ADC).

    CD-ROM drive and laser discs

    The main carrier for multimedia programs in the world is the CD-ROM laser disk. This brilliant disc, no different in appearance from an Audio CD, holds up to 650 MB of information in such forms as video, audio, text, graphics and animation. The same amount of information can fit on 250,000 pages of printed text or on 8 meters of bookshelves. This explains the widespread use of CD-ROMs in the world.

    CD drives are produced by such well-known companies as Sony, NEC, Panasonic, Plextor, Creative. Reading data from CDs occurs using a laser beam, which reads information from micro-tracks printed on the CD. Data is read at a speed of 150 kb/s. At this speed, drives are called single-speed drives. Now these drives are obsolete, instead they began to produce faster 2-, 3-, 4-x, 6-, 8-speed drives. That is, reading occurs 2,3,4,6,8 times faster. There are also faster CD-ROM drives, for example 16, 24, 32 speed, etc.

    Multimedia presentations

    A multimedia presentation is a multimedia product, which may include text and text special effects, speech and music, animations, video clips, galleries of pictures and slides (slide shows), etc.

    Multimedia presentations are widely used when creating educational programs, including those on laser discs, when creating advertising videos, video clips, etc. There are a number of programs that allow you to create multimedia presentations, for example MicroSoft PowerPoint (4.0, 7.0, 97). Among these programs, programs that can capture screen videos and convert them into AVI and EXE video files are of great importance. Such programs include MicroSoft Camcorder, Hiper Cam, Lotus ScreenCam. However, these presentations are not interactive, but they can be part of a larger interactive presentation.

    Great opportunities for creating multimedia presentations are provided by the use of Internet technologies, for example, the use of the HTML language editor and the MicroSoft Internet Explorer Web page viewer, which is installed on most modern computers. In the simplest case, you can use the Notepad editor for Windows as an HTML language editor. This technology is much simpler than using PowerPoint, and its efficiency is quite high (at the level of the capabilities of the Internet computer network).

    You can create Web pages in HTML - htm or html files containing text, pictures, animations, speech and music, video clips, interconnected by hypertext links. By moving from one Web page to another using hypertext links, you can create an interactive multimedia presentation (multimedia project) on any topic using buttons and other dialog elements.

    Slide 2

    These days, almost every home computer comes with a sound card. It's almost standard. Sound cards allow you to listen to recordings from CDs, MPEG-3 and RealAudio files, enjoy computer games, work with Internet phones, Internet radio stations or news servers. If you are going to use a computer for sound recording, you cannot do without a sound card.

    Slide 3

    A sound card can be equipped with speakers and a joystick for games, and then we call it a sound box. If there are no speakers, then any external amplifier, headphones or cassette recorder will do for playback. Today on the market you can find sound cards costing from 12 to 1000 dollars and even more. The price lists of computer companies offer a wide range of sound cards. It was this card that at one time was the first sound card that cost less than 100

    Slide 4

    Classification of sound cards.

    Since the advent of sound cards (80s), they have been classified according to their ability to reproduce sound recorded digitally and, if possible, to synthesize it. In accordance with this, at least three classes of audio cards are distinguished: Sound cards - contain only a digital recording/playback path; accordingly, such devices only allow recording (digitizing) or playing back a continuous audio stream. The work of storing the recorded stream and preparing the playback stream is assigned either to the software or to the signal processor built into the sound card. The first sound cards "Computer" with the first sound card

    Slide 5

    Musical – contain only a musical synthesizer. Such devices are focused primarily on generating musical sounds, which are created parametrically (by harmonic signal generators) or by playing a pre-recorded set of reference sounds. It is obvious that neither one nor the other class of sound cards fully meets the modern requirements placed on them: the latter in most cases belong to the class of combined (sound-musical) devices that combine the functions of the first two classes of sound cards. A synthesizer (synthesio - I do) is a device that creates sound. In computer sound card terminology, a synthesizer is the part of the sound card that is responsible for generating sounds and music.

    Slide 6

    Main characteristics of sound cards:

    The sampling (digitizing) frequency of the signal must be at least twice the maximum frequency of the input signal (according to Kotelnikov’s theorem). If human speech occupies a frequency band of up to 3–4 kHz, then a frequency of 8 kHz is required to digitize it. Modern sound cards support sampling rates of 8.0–192 kHz, which corresponds to signals with frequencies up to 96 kHz.

    Slide 7

    Bit depth and dynamic range. Modern sound cards allow you to record sound with a resolution of 8, 16 and 24 bits, which corresponds to 256, 65536 and 16.7 million different signal levels. This parameter, first of all, determines the dynamic range of the reproduced sound, that is, how many times the intensity of the loudest sound can be greater than the intensity of the quietest sound. This quantity is usually expressed on a logarithmic scale and measured in decibels. For 8-bit audio, the dynamic range is only 48 dB, for 16-bit it is 96 dB, and for 24-bit it is 144 dB. ASUS Xonar: 1987 - the first sound card for PC appeared - AdLib Perhaps the first sound card “tailored” for home theater

    Slide 8

    The signal-to-noise ratio (S/N or SNR – Signal to Noise Ratio) shows how many times the signal volume is greater than the noise volume that occurs in the sound card for various reasons, primarily as a result of sampling error. Sampling noise is always present and is at least half the least significant bit, so, for example, the signal-to-noise ratio for a 16-bit board cannot be better than 93 dB (i.e. 96–6:2). Various sound cards: Xonar (01.jpg, 448×310, 12 KB) Auzen_X-FI.jpg, 380×252, 30 KB

    Slide 9

    Total Harmonic Distortion (THD). Nonlinear distortion is the result of inaccuracy in the restoration of a signal from digital to analog. The coefficient of nonlinear distortion is measured as a percentage: 1% – “dirty” sound; 0.1% – normal sound; 0.01% – pure Hi-Fi sound; 0.002% – Hi-Fi – Hi End class sound. This is the first sound card from Icemat jpg, 130×127, 2 KB ASUS announced its first sound card at Computex 2007. 387422_01_thumb.jpg, 133×100, 15 KB At CeBIT 2007, Creative demonstrated its first sound card. hifi.gif, 250×250, 22 KB

    Slide 10

    Supported special effects. Special effects supported by sound cards include reverb, chorus, and various 3D enhancements. All special effects are the result of sound processing, which refers to the transformation of sound data in order to change the sound characteristics. The main methods of converting audio data are amplitude, frequency, phase and time conversions. E-Mu 18204696_big.jpg, 360×260, 37 KB E-MU 011_1.jpg, 200×200, 14 KB

    Slide 11

    Amplitude transformations. They are performed on the amplitude of the signal and lead to its amplification/weakening or change according to some law in certain parts of the signal. Frequency conversions. They are performed on the frequency components of sound: the signal is presented in the form of a frequency spectrum at certain time intervals, the necessary frequency components are processed, for example, filtering, and the signal is reversed from the spectrum into a wave. Phase transformations – shifting the phase of the signal in one way or another; for example, converting a stereo signal allows you to realize the effect of rotation or “volume” of sound. Temporary transformations. They are implemented by superimposing, stretching/compressing signals, which allows you to control the spatial characteristics of the sound.

    Slide 12

    Echo effect. Implemented using time transformations. In fact, to obtain an echo, it is necessary to superimpose a time-delayed copy of the original input signal. Repetition effect (Reverberation). The effect is to give the sound the volume characteristic of a large hall, where each sound generates a corresponding, slowly fading echo. Audigy4,bulk Creative System Requirements:Intel® Pentium® III or Celeron 800MHz,or AMD® 1GHz or faster,Intel®,AMD®,Microsoft® Windows® XP (SP2),Windows 2000(SP4) or Windows Professionalx64,128 MB RAM ,600MB HD

    Slide 13

    Chorus effect. As a result of its application, the sound of the signal turns into the sound of a choir or the simultaneous sound of several instruments. The scheme for obtaining this effect is similar to the scheme for creating the echo effect, with the only difference being that the delayed copies of the input signal are subjected to weak frequency modulation before mixing with the input signal. Increasing the number of voices in a choir is achieved by adding copies of the signal with different delay times. To improve the quality of sound reproduction, audio devices implement various multichannel audio encoding schemes, the most common of which are the following: DSS, DPL, THX, AC3, Dolby Digital EX, DTS, etc.

    Slide 14

    One of the newest sound cards. Terratec Producer Phase 88 Average price: RUR 11,561 (from 8,093 to 15,029 rubles) General characteristics: Type - internal with an additional block.; Connection type - PCI; Sound scheme -7.1; Sound characteristics: DAC/ADC bit depth - 24 bit/24 bit Maximum DAC frequency (stereo) -96 kHz Maximum DAC frequency (multichannel) -96 kHz Signal/noise ratio DAC/ADC -110 dB/100 dB

    Slide 15

    Standards support: EAX version - no; ASIO - 2.0 support. Connection: Digital interfaces S/PDIF - coaxial input, coaxial output; Support for external synchronization – yes. Number of external linear inputs – 8; Number of microphone inputs - 1; Availability of preamplifiers - yes; MIDI interfaces - inputs/outputs - 1/1 Number of independent headphone outputs - 1.

    Slide 16

    The authors of the presentation “Sound Cards” are 10th grade students, Municipal Educational Institution “Secondary School No. 4” KOVINA DARIA and SEREBRYAKOVA ANNA. The materials used are taken from the Internet, as well as pictures from the school archive and personal drawings, pictures and music provided by the creators of the presentation. We would like to thank Fazylov Dinis and Khasanov Ruslan for their help in creating the presentation. 09/26/2007.

    View all slides

    Computer Science Presentation - Sound cards

    These days, almost every home computer comes with sound card. It's almost standard. Sound cards allow you to listen to recordings from CDs, MPEG-3 and RealAudio files, enjoy computer games, work with Internet phones, Internet radio stations or news servers. If you are going to use a computer for sound recording, you cannot do without a sound card.

    Sound card can be equipped with speakers and a joystick for games, and then we call it a sound console. If there are no speakers, then any external amplifier, headphones or cassette recorder will do for playback.
    Today on the market you can find sound cards costing from 12 to 1000 dollars and even more. The price lists of computer companies offer a wide range of sound cards.

    Classification of sound cards.
    Since the advent of sound cards (80s), they have been classified according to their ability to reproduce sound recorded digitally and, if possible, to synthesize it.
    In accordance with this, there are at least three classes of audio cards:
    Audio - contain only a digital recording/playback path; accordingly, such devices only allow recording (digitizing) or playing back a continuous audio stream. The work of storing the recorded stream and preparing the playback stream is assigned either to the software or to the signal processor built into the sound card.

    Musical– contain only a music synthesizer. Such devices are focused primarily on generating musical sounds, which are created parametrically (by harmonic signal generators) or by playing a pre-recorded set of reference sounds.
    It is obvious that neither one nor the other class of sound cards fully meets the modern requirements placed on them: the latter in most cases belong to the class of combined (sound-musical) devices that combine the functions of the first two classes of sound cards.
    Synthesizer(synthesio - I do) is a device that creates sound. In computer sound card terminology, a synthesizer is the part of the sound card that is responsible for generating sounds and music.

    Main characteristics of sound cards:
    The sampling (digitizing) frequency of the signal must be at least twice the maximum frequency of the input signal (according to Kotelnikov’s theorem). If human speech occupies a frequency band of up to 3–4 kHz, then a frequency of 8 kHz is required to digitize it. Modern sound cards support sampling rates of 8.0–192 kHz, which corresponds to signals with frequencies up to 96 kHz.

    Bit depth and dynamic range. Modern sound cards allow you to record sound with a resolution of 8, 16 and 24 bits, which corresponds to 256, 65536 and 16.7 million different signal levels. This parameter, first of all, determines the dynamic range of the reproduced sound, that is, how many times the intensity of the loudest sound can be greater than the intensity of the quietest sound. This quantity is usually expressed on a logarithmic scale and measured in decibels. For 8-bit audio, the dynamic range is only 48 dB, for 16-bit it is 96 dB, and for 24-bit it is 144 dB.

    The signal-to-noise ratio (S/N or SNR – Signal to Noise Ratio) shows how many times the signal volume is greater than the noise volume that occurs in the sound card for various reasons, primarily as a result of sampling error. Sampling noise is always present and is at least half the least significant bit, so, for example, the signal-to-noise ratio for a 16-bit board cannot be better than 93 dB (i.e. 96–6:2).

    Harmonic distortion factor(Total Harmonic Distortion, THD). Nonlinear distortion is the result of inaccuracy in the restoration of a signal from digital to analog. The coefficient of nonlinear distortion is measured as a percentage: 1% – “dirty” sound; 0.1% – normal sound; 0.01% – pure Hi-Fi sound; 0.002% – Hi-Fi – Hi End class sound.

    Supported special effects. Special effects supported by sound cards include reverb, chorus, and various 3D enhancements. All special effects are the result of sound processing, which refers to the transformation of sound data in order to change the sound characteristics. The main methods of converting audio data are amplitude, frequency, phase and time conversions.

    Amplitude transformations. They are performed on the amplitude of the signal and lead to its amplification/weakening or change according to some law in certain parts of the signal.
    Frequency conversions. They are performed on the frequency components of sound: the signal is presented in the form of a frequency spectrum at certain time intervals, the necessary frequency components are processed, for example, filtering, and the signal is reversed from the spectrum into a wave.
    Phase transformations – shifting the phase of the signal in one way or another; for example, converting a stereo signal allows you to realize the effect of rotation or “volume” of sound.
    Temporary transformations. They are implemented by superimposing, stretching/compressing signals, which allows you to control the spatial characteristics of the sound.

    Echo effect(Echo). Implemented using time transformations. In fact, to obtain an echo, it is necessary to superimpose a time-delayed copy of the original input signal.
    Repetition effect (Reverberation). The effect is to give the sound the volume characteristic of a large hall, where each sound generates a corresponding, slowly fading echo.

    Chorus effect(Chorus). As a result of its application, the sound of the signal turns into the sound of a choir or the simultaneous sound of several instruments. The scheme for obtaining this effect is similar to the scheme for creating the echo effect, with the only difference being that the delayed copies of the input signal are subjected to weak frequency modulation before mixing with the input signal. Increasing the number of voices in a choir is achieved by adding copies of the signal with different delay times.
    To improve the quality of sound reproduction, audio devices implement various multichannel audio encoding schemes, the most common of which are the following: DSS, DPL, THX, AC3, Dolby Digital EX, DTS, etc.
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