High fidelity

High fidelity, often called hi-fi, refers to the clear and accurate way of playing back sound. It is loved by people who enjoy listening to music and sounds through good quality audio equipment at home. In an ideal high-fidelity system, there is almost no unwanted noise or changes to the sound, and it reproduces frequencies just as we hear them in real life.

This idea of high fidelity is different from lo-fi, which stands for low fidelity. Lo-fi sound comes from cheaper equipment, like old AM radios or early audio recordings made before the late 1940s. These systems often produce sounds that are not as clear or accurate as high-fidelity systems.

History

Bell Laboratories started testing new ways to record sound in the early 1930s. They recorded performances by Leopold Stokowski and the Philadelphia Orchestra using telephone lines between Philadelphia and New Jersey. Some early recordings were made on film, which helped improve sound quality for movies made by MGM and Twentieth Century Fox Film Corporation.

After World War II, new inventions helped make home audio much better. Better recording tapes allowed artists like Bing Crosby to create clearer records. New types of records called long play vinyl records could hold entire classical music pieces. Better turntables, FM radio, improved amplifiers, and new loudspeaker designs all contributed to richer, more accurate sound. In the 1950s, people began calling these high-quality systems high fidelity, or hi-fi, and many bought them to enjoy clearer music at home.

Listening tests

See also: Codec listening test

Listening tests help people check how good sound equipment is. Experts use these tests to see if small changes in sound matter. Sometimes, people might favor certain brands without realizing it. To avoid this, researchers use blind tests where listeners cannot see what they are listening to.

One common blind test is called the ABX test. Listeners hear two known samples — one called A (the reference) and one called B (an alternative) — and one unknown sample X. X is randomly chosen to be either A or B. The listener then guesses whether X is A or B. This helps make sure the test is fair and not influenced by personal preferences.

Semblance of realism

Sterephonic sound helped make music sound more like being in a concert by letting listeners hear instruments separated and creating a feeling of space. Later, some people tried using four speakers instead of two, called quadraphonic sound, but most didn’t like paying more for small changes.

For music to sound real, it needs to be clear without extra noise. CDs can play music very loudly and quietly, more than what we usually hear in concerts. They can also play all the notes people can hear, from very low to very high, which helps music sound true to life. Good audio equipment should play these notes clearly without changing how they sound.

Modularity

Integrated, mini, or lifestyle systems, sometimes called music centres or midi systems, combine sources like a CD player, a tuner, or a cassette tape deck with a preamplifier and a power amplifier in one box. One downside is that if a part breaks, you might need to replace the whole unit because the parts can't usually be swapped out easily.

Many audiophiles prefer building a system from separate pieces, often choosing each part from different specialists. This gives more flexibility for upgrades and repairs. A preamplifier and power amplifier together in one box is called an integrated amplifier, and adding a tuner makes it a receiver. Other system parts can include items like cartridges, tonearms, hi-fi turntables, digital media players, and DVD players.

Modular systems let enthusiasts pick exactly what they need and spend as much or as little as they want on each part. If one part stops working, the others can still work. However, these systems can be more complicated because they need many cables and often different remote controls for each unit.

Modern equipment

Some modern high-quality sound equipment can connect digitally using fiber optic TOSLINK cables, USB ports, Bluetooth, or Wi-Fi support.

Another modern part is the music server, which uses one or more computer hard drives to store music as computer files. When music is stored in special audio file format that keeps all details, like FLAC, Monkey's Audio or WMA Lossless, a computer can play the music at a very high quality for a sound system. Some streaming services now offer higher-quality sound options. Services like Tidal have added a high-quality level that includes special studio versions of many songs for desktop players, and this can also work with advanced audio systems.