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شهروالنيظام™
SOUND SYSTEMINTRODUCTION
Mono System
Surround System
Quad System
Stereo System
شهروالنيظام™
PUBLIC ADDRESS SYSTEM
Equipment maintenance
Sound system installation
Reinforcement equipment
Sound reinforcemant
Method of power distribution
PUBLIC ADDRESS SYSTEM
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Sound : The perception of the dinamic convergence and
vacuum air pressure level in ear. Audio : Produce from sound to electronic Sound wave : Generate from vibration/ shake.
The air molecul near to the shaking source will shake too. Sound wave is produce when the molecul move reverse in position same with the shaking object.
Amplitud & strength of sound : The number of moving molecul described the strength of sound and this is called – sound amplitud ( measured in dB )
Acoustic pressure is measured in Sound Pressure Level.
Dinamic range : Range from silence sound level to a noisy sound level that can be heard.
Monaural : Sound from Headphones Monophonic : Sound from speaker.
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0 Hz
20 Hz
20kHz
∞
Sound Pressure Level (SPL) –
SPL = 20 log Po/ 2 x 10⁻⁵ dB
* Po – Sound power level
2 x 10 ⁵ - Min. pressure of sound⁻
Human hearing level - 0 dB-SPL to 120 dB- SPL
( ear will start feel the pain)
The Biology of Ear :
• Divided to 2 area :
i. External – Directional sound area (sound calyx)
ii. Intermediate – Gegendang (reception of different type of
sound freq)
- Differentiate between human and the animal
Infrasound
Hearing band
(Sound Freq :
Ultrasound
100 Hz ~ 5kHz)
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Mono system – Depand to one recording system and sound channel.
i.e. – telephone system (monaural system). Whereas, radio broadcasting and sound system at cinema (monophonic system).
Monaural : Sound from Headphones Monophonic : Sound from speaker. Info from mono system ≠ original info if the
audience concentrate. Because the microphone pick the sound signal from one point whilst audience can hear sound from two points.
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• Stereo system – audio system that produce sound from 2 direction. • The good stereo system can produce sound illusion (position are fixed – cross the sound stage). In hi-fi system it is called stereo image. • User can separate and compare the sound o/p where the sound quality can be adjusted by considering the sound balance.
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SISTEM QUAD• QUADRAPHONIC @ 4 audio speaker system.• To boost the stereo sound.• Better sound spreading compare to stereo sound system with 2 speaker. • Surround @ rear speaker – for environment
sound.• This system are used to compressed the audio
o/p. i.e Concert
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Dolby Surround - New dimension of sound addition to
common stereo sound. - Using Dolby MP Matrix Encoder ~
encod 4 audio channel to 2 audio channel for stereo broadcasting programme.
SurroundSurround
L C R
Layout for stereophonic sound / Dolby Stereo
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5.1 Channel System
This system have 5 channel - frequency range from 3Hz to 20 KHz for front, left and right, center, surround o/p and additional of LFE (Low Freq. Effect) Sub-Woofer - freq range from 3 Hz to 120 Hz.
Dolby Digital Encoder
Producer/Mixer Multi Channel Audio
L
C
R
Ls
Rs
Digital Media
Digital Bit Stream
A/V comp. with Dolby Digital decoder
L
C
R
Ls
Rs
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When sampling the wave with an analog-to-digital converter, two variables need to be controlled :
The sampling rate - Controls how many samples are taken per second
The sampling precision - Controls how many different gradations (quantization levels) are possible when taking the sample
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PUBLIC ADDRESS SYSTEM (SISTEM SIARAYA)Necessary for the user that is far away from the sound source. Basic requirement ; microphone, amplifier and speaker.
P.A. system divided to 2 level :- High level system - wide area i.e Mosque, stadium and useful for for place which is crowded with people - Low level system - narrow area i.e. meeting room and place
which have a few people only. Divided to 3 category :- A Category – Open area ~ audiens > 5000 B Category – Inside hall ~ audiens > 1000 C Category – Inside hall ~ audiens ≈ 500
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PERALATAN SISTEM BUNYI MASJID
COLUMN SPEAKER
HORN SPEAKER
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The effeciency of P.A. systemDepend to :-i. Sound strength – sound that have enough strength to be heard at all position in one area. ii. Sound quality – The clear sound condition. Low freq need to be reduce @ adjusted in a closeted place. Also reduce the sound transmission to the mic to avoid sound interrupt. iii. Sound balance – To makesure sound not interrupted to any other influence. The sensitivity and tone control need to be test from every input area before the function start. iv. Direction effect – To makesure audience received suitable sound direction & not from multiple direction. Speaker should be positioned at correct angle and the distance between mic and speaker ≈ 7 meter.
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MIC
Main ClusterFill System
Cover by fill speaker Cover by main cluster
Rear Fill System
Cover by rear fill system
MIC
Main Cluster
Fill System
Balcony
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3 procedure on selecting and setting the sound system
• Determine the function and the reason why the audio system and the installation equipment is used.
• Before start the equipment installation for audio system, detail planning is needed to understand the specification & cost estimation.
• Others factor that relates is as below :- Study the sound condition in the area.Audio system selection and the determine the position of installation.Draw the block diagram of the system, circuit diagram, arrangement & specification.Wiring & installation for the audio system equipment have been selected.
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Additional equipment in P.A.
1. Microphone - Convert acoustic energy to
electric energy
- Able to convert in same value ---
sound wave electric sound ----
in wide range - Electrostatic, moving coil
& ribbon - Need good ratio between
sound & noise.
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2. Speaker - Mono speaker : give distance info
only.
- Stereo amplifier – give position info and separation sound.
- Type of speaker :-a. Moving coil - Common use. Able
to stand overload / Coil place at the magnet chink.
b. Piezoelectric - Good for high freq / i.e. watch
c. 2 way speaker – suitable for sound reinforcement / Freq range suitable to be heard.
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LINE ARRARY SPEAKER
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3. Amplifier- Amplify audio signal.- Tone control available. - Power per channel not more
than 100W- Input signal from CD have
better distortion compare to the cassette i/p.
MIXING AMPLIFIER/PUBLIC ADDRESS
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Method of Power line distribution to
the speakers
Speaker selection based on : – - Sound strength - Speaker quantity - Low power amplifier –
slow sound - High power amplifier –
damage the speaker
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For o/p amplifier low impedance;
- total impedance value for all speakers should higher @ same value with the o/p amplifier
Total o/p amplifier ≤ Combination of speaker
impedance impedance For o/p amplifier high impedance ; - total power supplied to the speaker
should be lower than the o/p amplifier capability.
Total power supplied to speaker ≤ o/p amplifier
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Low Impedance Amplifier Amplifier produce full power o/p. The amplifer attached with speaker
connection point that is labelled with ‘Com., 4Ω, 8Ω dan 16Ω’.
Variety connection of the speaker method can be implement as long as the total impedance connected to the amplifier is suitable with the value of the amplifier terminal connection point.
16Ω
8Ω4Ω
Com.
4Ω8Ω 4Ω
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High impedance amplifier Speaker installation method for this amplifier is
called ‘Constant Voltage Distribution System’ (Sistem Agihan Voltan Tetap)
The amplifer attached with speaker point that is labelled with ‘Com., 4Ω, 8Ω dan 16Ω’.
All the speaker connection is in parallel via transformer for impedance matching.
Voltage distribution value normally from 70V – 100V.
High impedance terminal
Low impedance terminal
CC
CC
CC
Primary Secondary
70V @ 100V line
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Type of the speakers & the range that will divide the speaker categories.
High impedance
Mark at the amplifier for high impedance connection
mark of 70V, 100V & 110V.
Speaker condition For range more than 10 m. Every speaker is attached with MT. Horn type speaker.
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Matching Transformer (MT)
Attached with Horn Speaker type.
MT will match power which was produced
by amplifier with rating to Horn speaker.
In other words, amplifier will induce MT and MT's output power to produce Horn speaker sound.
This method can extend life time’s of the
speaker.
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Type of speakers & the range that will divide the speaker categories.
Low impedance
Mark at the amplifier for low impedance connection
Mark of 4Ω, 8Ω & 16Ω.
Speaker condition that is categorized as high impedance connection
For range less than 10 m. Speaker value – not same Papercone & ceiling type speaker.
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Speaker Selection Avoid non clearity problem and
low power sound. Class of Speaker 1. Open place - freq waveform
between 800 Hz ~ 6000 Hz 2. Music background – for gentle
music freq between 100 Hz ~ 800Hz
3. Music – refer to the hall condition/ design for music 40Hz ~15000Hz
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Speaker Arrangement 1. Main System - Speaker place at the center of the hall to control sound convergence to one direction. Low maintenance cost. 2. Spreading System - Scattered arrangement for speakers. - Speaker combination can strengthen sound at the small space. - However the sound quality is reduce. 3. Combination System - Combination of 2 system.
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Arrangement & Speaker power distribution at
the internal building area. When setting the location of speaker in
a room, factor of level of noise, height of ceiling, wide area of the room, use of the speaker & etc.
Below shows the criteria taken on speaker installation :-Speaker Keluasan kawasan bagi memperolehi 76dB
keluaran maksima
WT – 707N (7W)
WT – 715N (15W)
WT – 202AN (10W)
WT – 200AN (15W)
Kira-kira 32m persegi
Kira-kira 64m persegi
Kira-kira 80m persegi
Kira-kira 100m persegi
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Introduction to the Sound Reinforcement system and the different with the PA system.
Sound Reinforcement system is used to produce an high energy sound signal in a wider area.
Suitable for musical & vocal while PA system is suitable for speech and lecture session.
Additional equipment can increase the capability of PA system to be a sound reinforcement system.
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The different between PA system and Sound Reinforcement system.
PA System Sound Reinforcement
Limited space for equipment.
Wide area for equipment
Level of sound spreading are not wider.
Wider of level of sound spreading
Lower cost More expensive cost
Low level of power & equipment consumption.
High power and use many equipment.
Suitable for general broadcasting
Suitable for music
Have 1 output channel Have 2 output channel
1 channel o/p connected to a numer of speaker
2 o/p channel which each o/p have 1 speaker
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Speaker
PointB Point A Point C
Determination of Speaker Location
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DVD Player Equalizer Limiter
Crossover
Speakers
Sub-woofer
Amplifier
Amplifier
Wireless Mic
Mixer
Microphone
SOUND SYSTEM FOR 300 PEOPLE
Canon jack to mono jack cable
2 to 2 rca plug
3 to 3 rca cable
Speakon plug to speakon plug cable
Speakon plug to speakon plug cable
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Additional equipment for
Sound Reinforcement
System
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AUDIO COMPRESSOR
Audio compressor – to compress @ limitting audio signal range.
Automatically fixed the signal level before send it to tape for recording
The compress process – to allow high/ low sound to be adjusted.
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Basic control system in the compressor for user :-
* I/P – Set i/p level
* Treshold – set level as a reference
before the compressor operate.
* Ratio – Set ratio to the rise of dB
at the signal below treshold level.
i.e. : Set 4:1 – bila treshold level dicapai, hanya 1dB kenaikan pd
o/p utk setiap 4dB kenaikan pd i/p
signal.
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* Attack – Time taken to act when the signal cross the treshold level. * Decay – Time taken back to normal condition when the
signal become below the treshold
level.
* O/P - Set o/p level.
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شهروالنيظام™
AUDIO COMPRESSORCircuit Operation
IC1 act as amplifier where the gain determine by the R1– resistor between Drain & Source FET 2N3819. R1, R2 & R3 determine FET V-I characteristic.
O/p circuit connected with the feed back circuit.
Attack and Decay controlled by R4 (1ms) and R5 (517ms)
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AUDIO COMPRESSORCircuit Operation
2 way switch – select compressor working condition –fix gain @ adjustable.
VR1 – adjustable gain R4, R5 & feedback connection
– fixed gain In this circuit, a 29dB change
in the input signal level produces a 9dB change in the output.
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AUDIO MIXER
Audio mixer is used to mix many type of i/p sound signal.
Normally there is 8 ~ 10 input. Low freq., mid range freq. &
high freq. The gain for i/p signal can be
controlled to follow needs of user @ to get any special effect.
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AUDIO GRAPHIC EQUALIZER Problem encounter - copying video
tapes is the deterioration in the sound quality.
To correct the sound signal to produce the o/p sound approx. near to the original sound. ( by correcting the freq response ) .
5 band equalizer design to connect 2 AV o/p component to produce freq response that can be controlled.
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The five controls each have a range of +/- 10dB at centre frequencies of 100Hz, 300Hz, 1KHz, 3KHz & 10KHz.
The 3dB points on each band are
at 1/2 and twice the centre frequencies.
Thus, the 3dB points on the 100Hz control are at 50Hz and 200Hz. With all controls at maximum the unit has a total gain of 15dB. The unit will accept an input of up to about 1V RMS (3V pk-pk) before distortion occurs with all controls at maximum.
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AUDIO GRAPHIC EQUALIZERCircuit operation
I/p is buffered by the IC1, (non-inverting with gain) which the gain can be controlled by altering R1 & R4.
For easier explaination, assume 5 frequency selective sections disappeared, as well as five of the control pots. The wiper of the remaining pot is connected to ground via a 1K0 resistor. So, the gain is 10.
So, if the 1k replaced back to the 5 band freq,
it shows that the gain can be adjusted.
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This cct is using capacitor and inductor in series connection as an adjuster. Gyrator model cct is used to replace the inductor due to difficulty
Refer to the cct, C2 - capacitor. Whereas, C3, R7 & R8 act as inductor. Value of C3 will determine the freq for each band.
In the last IC3 will function as Unity Gain buffer.
SW1 act as selector switch to select unit to be in equalizer mode or not.
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SOUND PROCESSOR
Function to change & adjust the sound structure to produce the best sound o/p.
The sound effect that can be produce by this processor is like echo (gema), surround (modulasi keliling) etc.
Normally used in the computer and television application.
* A rapid repetition of the same note, a rapid variation in the amplitude of a single note, or an alternation between
two or more notesThis is more usually called vibrato.
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Sound Delay Cct
To delay the signal, which makes the sound are far away.
Normally in surround decoder cct where the o/p will provide a passable rear channel signal.
As example, IC M65830 is use.
This IC need 5V supply. Whereas pin 11 & 12 need good separation between ground for analog and digital signal
DELAY +/-
I/P To O/P
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Cap 68nF at pin 16 & 20 – to control modulation ( conversion of digital & analog) & demodulation. However the tolerance should not exceeds 5% to get good result.
I/P driver cct – to decrease the i/p value signal to avoid overload. The max value for this IC i/p is 1 Vrms.
This is because signal for CD player normally at 2.5 Vrms. So, by using the driver cct, the signal can be decrease.
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