Understanding Sound and Audio Equipment: A Comprehensive Guide
Sound and Audio Equipment: A Comprehensive Guide
Understanding the Fundamentals of Sound
Sound
Sound is anything we hear. It is a longitudinal mechanical wave that propagates through elastic mediums such as air and water.
Sound Pressure
Sound pressure refers to the pressure variations produced by a sound wave as it travels through space.
Loudness
Loudness increases with the amplitude of vibration, which in turn increases the energy carried by the medium.
Wavelength
Wavelength is the distance between two successive peaks or two successive minimum values of pressure in a plane wave.
Tone
Tone, or sound quality, helps distinguish between different audio frequency spectrums (low, medium, and treble).
Timbre
Timbre is the characteristic that allows us to identify different musical instruments playing the same tone and intensity, even when emitted by sound sources of different natures.
Decibel
The decibel (dB) expresses the relationship between two quantities, acoustic or electric, or between the quantity being studied and a reference magnitude.
Loudness (Perceived)
Loudness represents the perceived intensity of a sound in our ears.
Sound Behavior and Phenomena
Reflection
Reflection occurs when a part of a sound wave bounces off a surface at an angle equal to the incident angle. The extent of absorption depends on the material.
Refraction
Refraction is the change in direction of a sound wave as it passes from one medium to another.
Diffraction
Diffraction occurs when a sound wave encounters a barrier or an opening and bends around it. This is more pronounced when the dimensions of the barrier or opening are smaller than the wavelength.
Echo
An echo occurs when the obstacle reflecting the sound waves is at a distance equal to or greater than 17 meters from the sound source.
Reverb
Reverb occurs when the obstacle reflecting the sound waves is at a distance less than 17 meters from the sound source.
Interference
Interference effects are produced when sound waves from multiple reflections of the direct wave interact with each other.
Distortion
Distortion is the presence of unwanted signals at the output of a system that were not present at the input.
Resonance
Resonance occurs when a material is struck and vibrates at its natural or dominant frequency.
Microphones: Capturing Sound
Microphone
A microphone is a device that converts sound waves into electrical signals.
Omnidirectional Microphone
Omnidirectional microphones have the same sensitivity to sound waves coming from all directions.
Bidirectional Microphone
Bidirectional microphones receive sound pressure from both the front and back of the diaphragm, attenuating sounds from other directions.
Unidirectional or Cardioid Microphone
Unidirectional microphones primarily capture sounds from the front and attenuate sounds from the rear.
Hypercardioid Microphone
Hypercardioid microphones have a very narrow pickup pattern at the front and a small lobe of sensitivity at the rear.
Shotgun or Interference Microphone
Shotgun microphones are designed to capture sound from a specific direction while rejecting sounds from other directions.
Carbon Microphone
Carbon microphones operate based on the principle of changing resistance in a carbon granule chamber due to sound pressure variations.
Electrodynamic Microphone
Electrodynamic microphones use a moving coil within a magnetic field to generate an electrical signal.
Piezoelectric Microphone
Piezoelectric microphones generate an electric charge when subjected to mechanical stress from sound pressure.
Dynamic Microphone
Dynamic microphones operate on the principle of electromagnetic induction, where a moving coil within a magnetic field generates an electrical signal.
Wireless Microphone
Wireless microphones consist of a microphone and a transmitter that sends the audio signal to a receiver.
Testing a Microphone
Dynamic microphones can be tested for continuity using a multimeter.
Speakers: Reproducing Sound
Dynamic Speaker
Dynamic speakers use an electromagnet to move a cone, generating sound waves.
Electrostatic Speaker
Electrostatic speakers use a thin diaphragm suspended between two charged plates to produce sound.
Piezoelectric Speaker
Piezoelectric speakers utilize the piezoelectric effect to convert electrical signals into mechanical vibrations.
Testing a Speaker
Speakers can be tested by measuring the resistance of the voice coil using a multimeter.
Audio System Components
Crossover
A crossover is a device that divides the audio signal into different frequency ranges and sends them to the appropriate speakers.
Bass-Reflex Subwoofer
A bass-reflex subwoofer uses a ported enclosure to enhance low-frequency sound reproduction.
Sound in Different Environments
Acoustical Environment
Acoustical environment refers to the way sound behaves in a particular space.
Paging
Paging systems are used to broadcast announcements or messages in a specific area.