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Audio Equipment Testing
Audio equipment testing is the measurement of audio quality through objective and/or subjective means. The results of such tests are published in journals, magazines, whitepapers, websites, and in other media. Those who test and evaluate equipment can be roughly divided into two groups: "Objectivists", who believe that all perceivable differences in audio equipment can be explained scientifically through measurement and double-blind listening tests; and the " Subjectivists", who believe that the human ear is capable of hearing details and differences that cannot be directly measured. Summary of Objective versus Subjective Audiophiles, in general: *Both agree that measurements are not a substitute for listening tests. *Both agree that different audio components may have different sound qualities. *Disagree that subjective listeners can overcome placebo and confirmation bias in non-blind listening tests. *Disagree about whether perceived sound quality can be measured through object ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objectivist (audio Term)
Objectivism is a philosophical system developed by Russian-American writer and philosopher Ayn Rand. She described it as "the concept of man as a heroic being, with his own happiness as the moral purpose of his life, with productive achievement as his noblest activity, and reason as his only absolute"."About the Author" in Rand first expressed Objectivism in her fiction, most notably ''The Fountainhead'' (1943) and '' Atlas Shrugged'' (1957), and later in non-fiction essays and books. Leonard Peikoff, a professional philosopher and Rand's designated intellectual heir, later gave it a more formal structure. Peikoff characterizes Objectivism as a "closed system" insofar as its "fundamental principles" were set out by Rand and are not subject to change. However, he stated that "new implications, applications and integrations can always be discovered". Objectivism's main tenets are that reality exists independently of consciousness, that human beings have direct contact with real ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Feedback
Audio feedback (also known as acoustic feedback, simply as feedback) is a positive feedback situation which may occur when an acoustic path exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for example, a loudspeaker). In this example, a signal received by the microphone is amplified and passed out of the loudspeaker. The sound from the loudspeaker can then be received by the microphone again, amplified further, and then passed out through the loudspeaker again. The frequency of the resulting howl is determined by resonance frequencies in the microphone, amplifier, and loudspeaker, the acoustics of the room, the directional pick-up and emission patterns of the microphone and loudspeaker, and the distance between them. The principles of audio feedback were first discovered by Danish scientist Søren Absalon Larsen, hence it is also known as the Larsen effect. Feedback is almost always considered undesirable when it occurs with a singe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safety Margin
Safety is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk. Meanings There are two slightly different meanings of ''safety''. For example, ''home safety'' may indicate a building's ability to protect against external harm events (such as weather, home invasion, etc.), or may indicate that its internal installations (such as appliances, stairs, etc.) are safe (not dangerous or harmful) for its inhabitants. Discussions of safety often include mention of related terms. Security is such a term. With time the definitions between these two have often become interchanged, equated, and frequently appear juxtaposed in the same sentence. Readers unfortunately are left to conclude whether they comprise a redundancy. This confuses the uniqueness that should be reserved for each by itself. When seen as unique, as we intend here, each term will a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super Audio CD
Super Audio CD (SACD) is an optical disc format for audio storage introduced in 1999. It was developed jointly by Sony and Philips Electronics and intended to be the successor to the Compact Disc (CD) format. The SACD format allows multiple audio channels (i.e. surround sound or multichannel sound). It also provides a higher bit rate and longer playing time than a conventional CD. An SACD is designed to be played on an SACD player. A ''hybrid SACD'' contains a Compact Disc Digital Audio (CDDA) layer and can also be played on a standard CD player. History The Super Audio CD format was introduced in 1999, and is defined by the ''Scarlet Book'' standard document. Philips and Crest Digital partnered in May 2002 to develop and install the first SACD hybrid disc production line in the United States, with a production capacity of up to three million discs per year. SACD did not achieve the level of growth that compact discs enjoyed in the 1980s, and was not accepted by the mainstr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neil Young
Neil Percival Young (born November 12, 1945) is a Canadian-American singer and songwriter. After embarking on a music career in Winnipeg in the 1960s, Young moved to Los Angeles, joining Buffalo Springfield with Stephen Stills, Richie Furay and others. Since the beginning of his solo career with his backing band Crazy Horse (band), Crazy Horse, he has released many critically acclaimed and important albums, such as ''Everybody Knows This Is Nowhere'', ''After the Gold Rush'', ''Harvest (Neil Young album), Harvest'', ''On the Beach (Neil Young album), On the Beach'' and ''Rust Never Sleeps''. He was a part-time member of Crosby, Stills, Nash & Young. His guitar work, deeply personal lyrics and signature high tenor singing voice define his long career. Young also plays piano and harmonica on many albums, which frequently combine folk music, folk, rock music, rock, country music, country and other musical genres. His often distorted electric guitar playing, especially with Cra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oversampling
In signal processing, oversampling is the process of sampling a signal at a sampling frequency significantly higher than the Nyquist rate. Theoretically, a bandwidth-limited signal can be perfectly reconstructed if sampled at the Nyquist rate or above it. The Nyquist rate is defined as twice the bandwidth of the signal. Oversampling is capable of improving resolution and signal-to-noise ratio, and can be helpful in avoiding aliasing and phase distortion by relaxing anti-aliasing filter performance requirements. A signal is said to be oversampled by a factor of ''N'' if it is sampled at ''N'' times the Nyquist rate. Motivation There are three main reasons for performing oversampling: to improve anti-aliasing performance, to increase resolution and to reduce noise. Anti-aliasing Oversampling can make it easier to realize analog anti-aliasing filters. Without oversampling, it is very difficult to implement filters with the sharp cutoff necessary to maximize use of the available b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Filter
In signal processing, a digital filter is a system that performs mathematical operations on a sampled, discrete-time signal to reduce or enhance certain aspects of that signal. This is in contrast to the other major type of electronic filter, the analog filter, which is typically an electronic circuit operating on continuous-time analog signals. A digital filter system usually consists of an analog-to-digital converter (ADC) to sample the input signal, followed by a microprocessor and some peripheral components such as memory to store data and filter coefficients etc. Program Instructions (software) running on the microprocessor implement the digital filter by performing the necessary mathematical operations on the numbers received from the ADC. In some high performance applications, an FPGA or ASIC is used instead of a general purpose microprocessor, or a specialized digital signal processor (DSP) with specific paralleled architecture for expediting operations such as filter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital-to-analog Converter
In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. There are several DAC architectures; the suitability of a DAC for a particular application is determined by figures of merit including: resolution, maximum sampling frequency and others. Digital-to-analog conversion can degrade a signal, so a DAC should be specified that has insignificant errors in terms of the application. DACs are commonly used in music players to convert digital data streams into analog audio signals. They are also used in televisions and mobile phones to convert digital video data into analog video signals. These two applications use DACs at opposite ends of the frequency/resolution trade-off. The audio DAC is a low-frequency, high-resolution type while the video DAC is a high-frequency low- to medium-resolution type. Due to the complexity a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passband
A passband is the range of frequencies or wavelengths that can pass through a filter. For example, a radio receiver contains a bandpass filter to select the frequency of the desired radio signal out of all the radio waves picked up by its antenna. The passband of a receiver is the range of frequencies it can receive when it is tuned into the desired frequency (channel). A bandpass-filtered signal (that is, a signal with energy only in a passband), is known as a bandpass signal, in contrast to a baseband signal. Filters In telecommunications, optics, and acoustics, a passband (a band-pass filtered signal) is the portion of the frequency spectrum that is transmitted (with minimum relative loss or maximum relative gain) by some filtering device. In other words, it is a ''band'' of frequencies which ''pass''es through some filter or a set of filters. The accompanying figure shows a schematic of a waveform being filtered by a bandpass filter consisting of a highpass and a low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Filter
An audio filter is a frequency dependent circuit, working in the audio frequency range, 0 Hz to 20 kHz. Audio filters can amplify (boost), pass or attenuate (cut) some frequency ranges. Many types of filters exist for different audio applications including hi-fi stereo systems, musical synthesizers, effects units, sound reinforcement systems, instrument amplifiers and virtual reality systems. Types ;Low-pass :Low-pass filters pass through frequencies below their cutoff frequencies, and progressively attenuates frequencies above the cutoff frequency. Low-pass filters are used in audio crossovers to remove high-frequency content from signals being sent to a low-frequency subwoofer system. ;High-pass :A high-pass filter does the opposite, passing high frequencies above the cutoff frequency, and progressively attenuating frequencies below the cutoff frequency. A high-pass filter can be used in an audio crossover to remove low-frequency content from a signal being sent to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Response
In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of systems, such as audio and control systems, where they simplify mathematical analysis by converting governing differential equations into algebraic equations. In an audio system, it may be used to minimize audible distortion by designing components (such as microphones, amplifiers and loudspeakers) so that the overall response is as flat (uniform) as possible across the system's bandwidth. In control systems, such as a vehicle's cruise control, it may be used to assess system stability, often through the use of Bode plots. Systems with a specific frequency response can be designed using analog and digital filters. The frequency response characterizes systems in the frequency domain, just as the impulse response characterizes systems in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Harmonic Distortion
The total harmonic distortion (THD or THDi) is a measurement of the harmonic distortion present in a signal and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. Distortion factor, a closely related term, is sometimes used as a synonym. In audio systems, lower distortion means the components in a loudspeaker, amplifier or microphone or other equipment produce a more accurate reproduction of an audio recording. In radio communications, devices with lower THD tend to produce less unintentional interference with other electronic devices. Since harmonic distortion tends to widen the frequency spectrum of the output emissions from a device by adding signals at multiples of the input frequency, devices with high THD are less suitable in applications such as spectrum sharing and spectrum sensing. In power systems, lower THD implies lower peak currents, less heating, lower electromagnetic emissions, and less core loss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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