|
Audio System Measurements
Audio system measurements are a means of quantifying system performance. These measurements are made for several purposes. Designers take measurements so that they can specify the performance of a piece of equipment. Maintenance engineers make them to ensure equipment is still working to specification, or to ensure that the cumulative defects of an audio path are within limits considered acceptable. Audio system measurements often accommodate psychoacoustic principles to measure the system in a way that relates to human hearing. Subjectivity and frequency weighting Subjectively valid methods came to prominence in consumer audio in the UK and Europe in the 1970s, when the introduction of compact cassette tape, dbx and Dolby noise reduction techniques revealed the unsatisfactory nature of many basic engineering measurements. The specification of weighted CCIR-468 quasi-peak noise, and weighted quasi-peak wow and flutter became particularly widely used and attempts were ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wow And Flutter Measurement
Measurement of wow and flutter is carried out on audio tape machines, cassette recorders and players, and other analog recording and reproduction devices with rotary components (e.g. movie projectors, turntables (vinyl recording), etc.) This measurement quantifies the amount of 'frequency wobble' (caused by speed fluctuations) present in subjectively valid terms. Turntables tend to suffer mainly ''slow wow''. In digital systems, which are locked to crystal oscillators, variations in clock timing are referred to as wander or jitter, depending on speed. While the terms ''wow'' and ''flutter'' used to be used separately (for wobbles at a rate below and above 4 Hz respectively), they tend to be combined now that universal standards exist for measurement which take both into account simultaneously. Listeners find flutter most objectionable when the actual frequency of wobble is 4 Hz, and less audible above and below this rate. This fact forms the basis for the weighting curve s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LP Album
The LP (from "long playing" or "long play") is an analog sound storage medium, a phonograph record format characterized by: a speed of rpm; a 12- or 10-inch (30- or 25-cm) diameter; use of the "microgroove" groove specification; and a vinyl (a copolymer of vinyl chloride acetate) composition disk. Introduced by Columbia in 1948, it was soon adopted as a new standard by the entire record industry. Apart from a few relatively minor refinements and the important later addition of stereophonic sound, it remained the standard format for record albums (during a period in popular music known as the album era) until its gradual replacement from the 1980s to the early 2000s, first by cassettes, then by compact discs, and finally by digital music distribution. Beginning in the late 2000s, the LP has experienced a resurgence in popularity. Format advantages At the time the LP was introduced, nearly all phonograph records for home use were made of an abrasive shellac compoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter (signal Processing)
In signal processing, a filter is a device or process that removes some unwanted components or features from a signal. Filtering is a class of signal processing, the defining feature of filters being the complete or partial suppression of some aspect of the signal. Most often, this means removing some frequencies or frequency bands. However, filters do not exclusively act in the frequency domain; especially in the field of image processing many other targets for filtering exist. Correlations can be removed for certain frequency components and not for others without having to act in the frequency domain. Filters are widely used in electronics and telecommunication, in radio, television, audio recording, radar, control systems, music synthesis, image processing, and computer graphics. There are many different bases of classifying filters and these overlap in many different ways; there is no simple hierarchical classification. Filters may be: * non-linear or linear * time-variant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equalization (audio)
Equalization, or simply EQ, in sound recording and reproduction is the process of adjusting the volume of different frequency bands within an audio signal. The circuit or equipment used to achieve this is called an equalizer. Most hi-fi equipment uses relatively simple filters to make bass and treble adjustments. Graphic and parametric equalizers have much more flexibility in tailoring the frequency content of an audio signal. Broadcast and recording studios use sophisticated equalizers capable of much more detailed adjustments, such as eliminating unwanted sounds or making certain instruments or voices more prominent. Since equalizers "adjust the amplitude of audio signals at particular frequencies" they are, "in other words, frequency-specific volume knobs." Equalizers are used in recording studios, radio studios and production control rooms, and live sound reinforcement and in instrument amplifiers, such as guitar amplifiers, to correct or adjust the response of mic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preamplifiers
A preamplifier, also known as a preamp, is an electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier and a loudspeaker. Without this, the final signal would be noisy or distorted. They are typically used to amplify signals from analog sensors such as microphones and pickups. Because of this, the preamplifier is often placed close to the sensor to reduce the effects of noise and interference. Description An ideal preamp will be linear (have a constant gain through its operating range), have high input impedance (requiring only a minimal amount of current to sense the input signal) and a low output impedance (when current is drawn from the output there is minimal change in the output voltage). It is used to boost the signal strength to drive the cable to the main instrument without significantly degrading the signal-to-noise ratio (SNR). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bass (music) Bass |
