1. Data dan Teknologi Multimedia Sesi 05 Nofriyadi Nurdam

2. At the end of this session, the students will be able to:  Show how to use sound on multimedia application.

3.  Sound Definition  Analogue to Digital Converter (ADC)  Digital Audio  MIDI (Musical Instrument Digital Interface)  Working with Sound

4. Sound  Sound are rapid vibrations that are transmitted as variations in air pressure  Sound comprises the spoken word, voices, music and even noise.

5. Bina Nusantara Sound  As the sound vibrates it bumps into molecules of the surrounding medium causing pressure waves to travel away from the source in all directions  Types of Sound in Multimedia: ◦ Speech ◦ Music ◦ Sound Effect

6.  Sound waves are manifest as waveforms ◦ A waveform that repeats itself at regular intervals is called a periodic waveform ◦ Waveforms that do not exhibit regularity are called noise  The unit of regularity is called a cycle ◦ This is known as Hertz (or Hz) after Heinrich Hertz  One cycle = 1 Hz  Sometimes written as kHz or kiloHertz (1 kHz = 1000 Hz)

7. distance along wave Cycle Time for one cycle

8. The characteristics of sound waves Sound waves AmplitudeFrequency

9. ◦ the rate at which sound is measured ◦ Number of cycles per second or Hertz (Hz) ◦ Determines the pitch of the sound as heard by our ears ◦ The higher frequency, the clearer and sharper the sound  the higher pitch of sound  Amplitude ◦ Sound’s intensity or loudness ◦ The louder the sound, the larger amplitude.  In addition, all sounds have a duration and successive musical sounds is called rhythm

10. distance along wave Cycle Time for one cycle Amplitude pitch

11. Bina Nusantara Piano Pan flute Snare drum

12. Air pressure variations Captured via microphone Air pressure variations ADC Signal is converted into binary (discrete form) 0101001101 0110101111 Analogue to Digital Converter DAC Convert s back into voltage Digital to Analogue Converter

13. The Analogue to Digital Converter (ADC)  An ADC is a device that converts analogue signals into digital signals  An analogue signal is a continuous value ◦ It can have any single value on an infinite scale  A digital signal is a discrete value ◦ It has a finite value (usually an integer)  An ADC is synchronised to some clock  It will monitor the continuous analogue signal at a set rate and convert what it sees into a discrete value at that specific moment in time  The process to convert the analogue to digital sound is called Sampling. Use PCM (Pulse Code Modulation)  When you present the sound wave as numbers, the process is called digitizing and the result will become digital audio

14. Digitized Sound  Is a sampled sound.  Every nth fraction of a second, a sample of sound is taken and stored as digital information 0110101110110110101101101 1011101101111011011101101 1011101111011011010101000 1011011011010110110100110 1101101101101101101010101 0100110011001001001100110 0110100110101110110110101 1011011011101101111011011 1011011011101111011011010 1010001011

15. Digital Sound Quality How often the samples are taken Sampling Rate (Frequency) How many numbers are used to represent the value of each sample Sample Size (Bitdepth) Quality of digital sound depends on

16. Digital sampling - Sampling Rate

18.  Sampling Rate ◦ Frequency of sampling ◦ Measure in Hertz ◦ The higher sampling rate, higher quality sound but size storage is big. ◦ Standard Sampling rate:  48.000 kHz (DAT) - Digital Audio Tape, also DVD  44.100 kHz (CD) - Compact Disk - typical quality of most sound cards  22.255 kHz - Medium quality  11.025 kHz - Low quality (frequently used for speech)

19.  Size sample ◦ The resolution of a sample is the number of bits it uses to store a given amplitude value, e.g.  8 bits (256 different values)  16 bits (65536 different values) ◦ A higher resolution will give higher quality but will require more memory (or disk storage)

21.  Samples are usually represented the audio sample as a integers(discrete number) or digital

22.  The formula is as follows:  The answer will be in bytes  Where: ◦ sampling rate is in Hz ◦ Duration/time is in seconds ◦ resolution is in bits (1 for 8 bits, 2 for 16 bits) ◦ number of channels = 1 for mono, 2 for stereo, etc.

23.  Example: ◦ Calculate the file size for 1 minute, 44.1 KHz, 16 bits, stereo sound ◦ Where:  sampling rate is 44,100 Hz  duration/time is 60 seconds  resolution is 16 bits  number of channels for stereo is 2 44100 * 60 * 16 *2 8

24.  One of the most powerful and professional PC-based software is previously known as Cool Edit. It’s now known as Adobe Audition. Same program, new company.

26.  Simple audio editing software allows: ◦ Recording of digital audio segments ◦ Trimming ◦ Splicing and assembly ◦ Volume adjustments of the entire segment ◦ Reversing Sounds ◦ Copy, cut, paste and delete segments of digital audio  Others audio editing software: ◦ Sound Forge ◦ Gold Wave ◦ PROSONIQ SonicWORX ◦ Samplitude Studio

27. . WAV (Developed by IBM and Microsoft) .AU (UNIX) .AIFF (Audio Interchange File Format) .MP3 (MPEG layer 3) .SND (Mac) .RA (RealAudio) .WMA (Windows Media Audio) .VOC (SoundBlaster)

28.  MIDI is a standard for specifying a musical performance  It allows different electronic devices to communicate together – Rather than send raw digital audio, it sends instructions to musical instruments telling them what note to play, at what volume, using what sound, etc.  The synthesiser that receives the MIDI events is responsible for generating the actual sounds. Example: Keyboard Piano  MIDI data is not digitized sound: it is a shorthand representation of music stored in numeric form

30.  A MIDI sequencer allows musicians to edit and create musical compositions like a word processor ◦ Cut and paste ◦ Insert / delete

31.  MIDI files are compact; the size of the file is completely independent of playback quality  In some cases MIDI may sound better than digital audio (if the MIDI sound source is of high quality)  MIDI data is completely editable: you can change the length of a MIDI file by varying its tempo without changing the pitch  Still used a lot in studio environment to connect synthesizers and other equipment

32.  MIDI does not represent sound but musical instruments, so playback is very rarely accurate (usually same score, wrong instrument)  MIDI cannot easily be used to play spoken dialog  An old format, people have already begun forgetting it

33. MIDI VS Wav Comparison Size storageCreationModificationPlayback Hardware Knowledge in music theory MIDI SmallMore DifficultEasierDependentRequired WAV Big sizeEasierMore DifficultIndependentNot required

34.  Cautions and warnings ◦ It is a good medium for alerting users to critical information. Some uses include:  Sounding an alarm when a limit is reached  Alerting users when data is entered incorrectly  Music and Sound Effects ◦ These make multimedia interaction more real. Some uses include:  Musical background for a video segment  Birds Songs accompanying photographs in biological field training

35.  Sound-related data. ◦ Some uses include:  Helping mechanics diagnose engine trouble  Training medical students to recognize different breathing sounds  Direct voice communication. ◦ Some uses include:  Leaving a voice message for other users of an application  Consulting with an expert during a troubleshooting procedure.

36.  Sound adds life to any multimedia application and plays important role in effective marketing presentations  Advantages ◦ Ensure important information is noticed ◦ Add interest ◦ Can communicate more directly than other medi  Disadvantages ◦ Easily overused ◦ Requires special equipment for quality production ◦ Not as memorable as visual media

37. Adding Sound to Multimedia Project  Determine the sound playback capabilities that the end user’s system offers  Decide what kind of sound is needed and where you’ll use them  Decide when to use midi and when to use digital audio  Acquire source material  Edit the sounds to fit your project  Test the sounds to be sure they are timed properly

38.  Decide what kind of sound is needed and where you’ll use them  Decide when to use midi and when to use digital audio  Acquire source material  Edit the sounds to fit your project  Test the sounds to be sure they are timed properly

39. Q & A