Audio Visual (AV) equipment can help enhance presentations, create an engaging atmosphere and share events with a broader audience. Furthermore, this equipment also ensures attendees can easily hear speakers and performers.
Audio equipment of crucial importance includes speakers, microphones and recording devices. Microphones amplify physical sound waves into electrical signals for further processing by recording devices; recording devices record these signals for future use.
Speakers
Speakers are transducers that convert electric signals into sound. Small speakers can be found in devices like radios, televisions, portable audio players and headphones while larger models may be found in home hi-fi systems (stereos), electronic musical instruments and concert halls/theatres for sound reinforcement purposes. Loudspeaker may refer to either individual drivers or complete systems of multiple drivers and their enclosures.
Modern speakers employ an electromagnet that converts electric signals of various strengths into movement of a coil of copper wire connected to cardboard, paper or vinyl cone that vibrates back and forth creating sound waves. It is controlled via electrical signal from an amplifier.
There are various factors that impact a speaker’s performance, including:
Chester W. Rice and Edward W. Kellogg invented the first speaker in the 1860s, yet it took 40 years before Chester W. Rice and Edward W. Kellogg perfected it by solving its final problems to produce clear audio output. To design a speaker successfully, engineers need a strong knowledge of electricity, sound waves, mathematics, mechanics and physics; to accurately anticipate how different components will interact and understand materials or construction limitations; they must also determine what type of enclosure should be used as well as power levels available to their designs.
Microphones
Microphones convert soundwaves into electrical signals that can be fed into an audio board for processing. Microphones are the cornerstone of professional recording studios where many different instruments and vocalists must simultaneously record high quality music recordings. Furthermore, microphones are frequently employed for public address systems, television and radio broadcasts, tape recorders, two-way radio communications, baby monitors and telephone use.
Microphone types can generally be classified by their transducer type and directional characteristics. Dynamic and condenser microphones, while end-address and side-address mics fall under this umbrella category.
Dynamic microphones are by far the most commonly used. They consist of a plastic diaphragm attached to a voice coil made up of multiple turns of very fine copper wire wound on a bobbin, all enclosed within a permanent magnet. Sound causes vibration of this diaphragm which then induces current in the voice coil in proportion with sound intensity; its voltage then detected by its amplifier and converted into digital output signaling.
Dynamic microphones are among the most sought-after options for professional use, offering exceptional sound pressure handling without distortion and are widely favored for recording drums, electric guitars, vocals and live performances. Their rugged construction also makes them suitable for recording in noisy environments – with sizes and colors designed to suit every application.
Compressors
Compressors increase the pressure of certain compressible gases or fluids, such as air. From compact models that fit easily in your glove compartment to much larger turbocompressors used to power industrial applications – compressors come in all shapes and sizes to meet any application need imaginable – compressors make your life more convenient while making vehicles safer – from air brakes on vehicle engines to theme park rides!
Compressors use rotors spinning inside sealed containers to pressurize atmospheric air into a chamber, before pumping it out at a lower rate into an output port at the output port – creating more pressure in turn and more compression. Their ratio, threshold level or ceiling, attack time and release time determine how aggressively they operate.
Hard knee compression allows the compressor to compress quickly and aggressively for an edgy sound, or it can be softened for a smoother sound. Release times may be as short as one second for rhythmic pumping effects or longer so as to allow dynamic control to “smooth out” over busier parts of a track.
An expander works the opposite of compression; it widens your dynamic range, making quiet parts louder and louder parts quieter. Knee, attack and release controls work similarly for expanders as for compressors; they even can be used for sidechain compression whereby an expander triggers when another audio element’s level changes (“Sound B”) fall below its threshold level, attenuating (or “eliminating”) it when it drops below that threshold threshold level.
Limiters
Similar to compressors, limiters are tools used to adjust the intensity of audio signals by restricting how much gain reduction occurs when they exceed a threshold value. Limiters are commonly employed during mastering as they help make mixes more consistent in terms of volume while simultaneously protecting peaks from clipping.
Limiters differ from compressors by having their ceiling level determined by threshold rather than ratio. This allows users to determine how loud a track should be as well as assist with making an informed decision as to whether or not using limiters is right for their mix.
Limiters often feature an attack and release control that allows users to regulate the rate at which it begins reducing signals once they exceed its threshold threshold. More aggressive limiter settings (in terms of attack and release settings) mean more aggressive signal limiting action; some limiters also feature knee controls which make limiting more gradual, giving your track a more natural sound. Modern limiters such as Waves L3-LL multimaximizer offer even greater flexibility, providing multiband limiting which helps preserve punchy and rhythmic elements of your mix without losing consistency or sound quality.
Amplifiers
Amplifiers take the weak signal generated by microphones or other devices and boost it to produce a stronger output, most commonly found in record player turntables, MP3 players and power amplifiers that drive speaker systems. They may also serve special roles such as pre-amplifiers that take in lower level signal before amplifying main amplifier or as servo motor controllers which use amplified control voltage to maintain constant speed or position in mechanical systems.
Understand the nature of amplifiers is vitally important as they don’t boost a constant electric current but rather a fluctuating one, necessitating faithful reproduction of fluctuating signals – an arduous task as audio signals vary both in frequency (measured as hertz Hz) and intensity/volume.
Amplifiers can be divided into several categories depending on how they handle different frequencies, with wideband amplifiers typically offering precise amplification over a wide frequency range and are often found in relay circuits. Narrowband amplifiers tend to operate within much narrower frequency bands and are commonly found in communications equipment – often made using microwave valves (klystron, gyrotron or traveling wave tube) that provide greater single device power output than transistors can; although semiconductor and solid state devices have increasingly replaced vacuum tubes as amps for most amplifiers.
Mixers
A mixer is an indispensable piece of equipment in any sound environment, responsible for accepting, combining and processing multiple inputs before outputting to speakers or recording devices. Some models also provide features to monitor or mix final mixes in studio environments.
Mixers assign each channel a particular type of signal (for instance a vocal mic or electric bass amplifier’s DI box signal). All signals enter via either XLR or RCA/quarter-inch TRS phone connector line inputs and all can be found through “polarity flip,” typically represented with an O symbol on their button/control. Polarity flip allows users to invert phase relationships between channels in order to prevent frequency buildups or cancellations which might negatively alter sound quality.
Most mixers feature a gain control that adjusts the level of signal at line level, usually proportional to input amounts. Furthermore, many have “line trim” controls to add or subtract line level gain depending on external device input levels.
The master section of a mixer contains buttons for changing the source of playback signal, altering monitor mix for performers on stage, setting stereo effect return destination, and other adjustments that affect all aspects of its output: these are called master controls.