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35-620: ABX may refer to: ABX test , a double-blind testing method commonly used in codec listening tests and in ascertaining high fidelity Abaknon language , an Austronesian language of the Philippines Albury Airport in Albury, New South Wales, Australia, from its IATA airport code Barrick Gold , from its TSX and NYSE stock symbol Antibiotics , antibacterial medications ABX Air An asset-backed securities index ABX diagnostics,

70-427: A 50% chance of choosing the correct answer, the same as flipping a coin. In order to make a statement having some degree of confidence , many trials must be performed. By increasing the number of trials, the likelihood of statistically asserting a person's ability to distinguish A and B is enhanced for a given confidence level. A 95% confidence level is commonly considered statistically significant . The company QSC, in

105-440: A keen interest in electronics and music. In 1967 Quilter had learned that the bass player in his brother’s high school band was searching for an affordable bass amp. When Quilter learned his budget was $ 250.00, he said “I could probably make you something for that kind of money,” giving birth to the first QSC amp. With many musician friends and acquaintances seeking him out to make guitar amps, he left school to start his company with

140-489: A medical device manufacturer, which was acquired by Horiba Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title ABX . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=ABX&oldid=1024856723 " Category : Disambiguation pages Hidden categories: Short description

175-413: A prominent player in cinema sound systems. In October of 2019, the company announced the acquisition of Attero Tech , expanding its portfolio of audio networked I/O endpoints. In June of 2023, Q-SYS acquired the swiss startup Seervision AG for an undisclosed amount, marking its first AI technology acquisition. The agreement is intended to pivot Q-SYS' focus onto intelligent video collaboration based in

210-666: Is also known as "duo–trio" in "balanced reference" mode – both knowns are presented as references, rather than one alone. QSC Audio Products QSC is an American manufacturer of audio, video and control products such as amplifiers, loudspeakers, cameras, video endpoints, and digital signal processors including the Q-SYS networked audio, video and control platform. QSC and Q-SYS products are used by audio and video professionals for commercial applications, including corporate, higher education, sports venues, themed entertainment, and cinema customers worldwide. The company holds five offices in

245-636: Is an implementation of the ODG . In MUSHRA , the subject is presented with the reference (labeled as such), a certain number of test samples, a hidden version of the reference and one or more anchors. A 0–100 rating scale makes it possible to rate very small differences, and the hidden version still provides discrimination checks. Alternative general methods are used in discrimination testing , such as paired comparison, duo–trio, and triangle testing . Of these, duo–trio and triangle testing are particularly close to ABX testing. Schematically: In this context, ABX testing

280-513: Is asked to make. During the first time interval he hears signal A, during the second, signal B, and finally signal X. His task is to indicate whether the sound heard during the X interval was more like that during the A interval or more like that during the B interval. For a threshold test, the A interval is quiet, the B interval is signal, and the X interval is either quiet or signal. The test has evolved to other variations such as subject control over duration and sequence of testing. One such example

315-425: Is different from Wikidata All article disambiguation pages All disambiguation pages ABX test ABX tests can easily be performed as double-blind trials , eliminating any possible unconscious influence from the researcher or the test supervisor. Because samples A and B are provided just prior to sample X, the difference does not have to be discerned using long-term memory or past experience. Thus,

350-494: The Amarok audio players support software-based ABX testing, the latter using a third-party script. Lacinato ABX is a cross-platform audio testing tool for Linux, Windows, and 64-bit Mac. Lacinato WebABX is a web-based cross-browser audio ABX tool. Open source aveX was mainly developed for Linux which also provides test-monitoring from a remote computer. ABX patcher is an ABX implementation for Max/MSP . More ABX software can be found at

385-511: The ABX Comparator user manual, recommended a minimum of ten listening trials in each round of tests. QSC recommended that no more than 25 trials be performed, as subject fatigue can set in, making the test less sensitive (less likely to reveal one's actual ability to discern the difference between A and B). However, a more sensitive test can be obtained by pooling the results from a number of such tests using separate individuals or tests from

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420-499: The ABX test answers whether or not, under the test circumstances, a perceptual difference can be found. ABX tests are commonly used in evaluations of digital audio data compression methods; sample A is typically an uncompressed sample, and sample B is a compressed version of A. Audible compression artifacts that indicate a shortcoming in the compression algorithm can be identified with subsequent testing. ABX tests can also be used to compare

455-616: The Q-SYS division delivers a software and hardware platform for networked audio, video and control, with products such as the Q-SYS Core Processors, NV Series video endpoints, NC Series PTZ Cameras, AcousticDesign loudspeakers, and more. The QSC Pro Audio division instead focuses on a range of non-networked amplifiers, loudspeakers, and line arrays for applications in performance venues, cinemas and event productions. On September 30th, 2016, QSC announced its acquisition of Ultra-Stereo Labs

490-577: The United States, including Austin, Boulder, Fort Wayne, San Luis Obispo, and its headquarters in Costa Mesa , with further international presence in London, Nieuwegein, Sinsheim, Zurich, Wattens, Dubai, Hong Kong, Beijing, Singapore, Bangalore, and Tokyo. The company was founded in 1968 by Patrick Howe Quilter, who serves as chairman of the board of directors. Quilter was at the time an engineering student with

525-488: The archived PCABX website. A codec listening test is a scientific study designed to compare two or more lossy audio codecs , usually with respect to perceived fidelity or compression efficiency. ABX is a type of forced choice testing. A subject's choices can be on merit, i.e. the subject indeed honestly tried to identify whether X seemed closer to A or B. But uninterested or tired subjects might choose randomly without even trying. If not caught, this may dilute

560-407: The artefacts they detect with each other. Other problems might arise from the ABX equipment itself, as outlined by Clark, where the equipment provides a tell , allowing the subject to identify the source. Lack of transparency of the ABX fixture creates similar problems. Since auditory tests and many other sensory tests rely on short-term memory , which only lasts a few seconds, it is critical that

595-444: The different degrees of fidelity loss between two different audio formats at a given bitrate . ABX tests can be used to audition input, processing, and output components as well as cabling: virtually any audio product or prototype design. The history of ABX testing and naming dates back to 1950 in a paper published by two Bell Labs researchers, W. A. Munson and Mark B. Gardner, titled Standardizing Auditory Tests . The purpose of

630-435: The digital domain over common Fast Ethernet media. In the late 1990s, QSC started a loudspeaker research and development group within its engineering department. Within a couple years, QSC offered loudspeaker systems for sale and is today a major supplier of loudspeaker systems in the professional audio industry. In July of 2022, QSC announced a split in its divisions, differentiating between Q-SYS and QSC Pro Audio. Today,

665-472: The early 1980s, Pat Quilter pursued his interest in more electrically efficient methods of power amplification by refining class G (and later, class H ) technology as an extension of class AB , primarily for higher-power models. In the early 1990s, QSC diversified from power amplifiers by starting development of network audio systems for remote control and monitoring of amplifier systems. QSC called its system QSControl (pronounced "Q's Control"). The company

700-581: The financial backing of family and friends. At first the company was a storefront operation in Costa Mesa, California, a combination of manufacturing and retail operations under one roof. The amplifiers were built in the back and sold out front. The first employees were mostly friends helping out. The early guitar amplifiers bore names like the Duck Amp and the Quilter Sound Thing . The company adopted

735-403: The grades are actual assessments of the impairments. 3.2.2 Post-screening of subjects Post-screening methods can be roughly separated into at least two classes; one is based on inconsistencies compared with the mean result and another relies on the ability of the subject to make correct identifications. The first class is never justifiable. Whenever a subjective listening test is performed with

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770-411: The inclusion of controls and the screening of subjects: A major consideration is the inclusion of appropriate control conditions. Typically, control conditions include the presentation of unimpaired audio materials, introduced in ways that are unpredictable to the subjects. It is the differences between judgement of these control stimuli and the potentially impaired ones that allows one to conclude that

805-403: The methods of their use. Subjects should also become thoroughly familiar with the artefacts under study. For the most sensitive tests they should be exposed to all the material they will be grading later in the formal grading sessions. During familiarization or training, subjects should be preferably together in groups (say, consisting of three subjects), so that they can interact freely and discuss

840-478: The name Quilter Sound Company, which was eventually shortened to the initials "QSC" and was known as QSC Audio Products, Inc. for many years. The company was officially renamed QSC, LLC in 2015. After some years, the professional power amplifier portion of the business overtook the production of guitar amplifiers. Meanwhile, QSC developed more conventional sales channels in retail music and pro audio stores and also started working with export distributors. Beginning in

875-401: The present paper is to describe a test procedure which has shown promise in this direction and to give descriptions of equipment which have been found helpful in minimizing the variability of the test results. The procedure, which we have called the "ABX" test, is a modification of the method of paired comparisons. An observer is presented with a time sequence of three signals for each judgment he

910-617: The results of other subjects who intently took the test and subject the outcome to Simpson's paradox , resulting in false summary results. Simply looking at the outcome totals of the test ( m out of n answers correct) cannot reveal occurrences of this problem. This problem becomes more acute if the differences are small. The user may get frustrated and simply aim to finish the test by voting randomly. In this regard, forced-choice tests such as ABX tend to favor negative outcomes when differences are small if proper protocols are not used to guard against this problem. Best practices call for both

945-480: The same subject conducted in between rest breaks. For a large number of total trials N, a significant result (one with 95% confidence) can be claimed if the number of correct responses exceeds N / 2 + N {\displaystyle N/2+{\sqrt {N}}} . Important decisions are normally based on a higher level of confidence, since an erroneous significant result would be claimed in one of 20 such tests simply by chance. The foobar2000 and

980-488: The switching is microprocessor controlled, double-blind tests are possible. Loudspeaker level and line level audio comparisons could be performed on an ABX test device offered for sale as the ABX Comparator by QSC Audio Products from 1998 to 2004. Other hardware solutions have been fabricated privately by individuals or organizations for internal testing. If only one ABX trial were performed, random guessing would incur

1015-474: The test fixture allows the subject to identify short segments that can be compared quickly. Pops and glitches in switching apparatus likewise must be eliminated, as they may dominate or otherwise interfere with the stimuli being tested in what is stored in the subject's short-term memory. Since ABX testing requires human beings for evaluation of lossy audio codecs, it is time-consuming and costly. Therefore, cheaper approaches have been developed, e.g. PEAQ , which

1050-472: The test method recommended here, the required information for the second class of post-screening is automatically available. A suggested statistical method for doing this is described in Attachment 1.' The methods are primarily used to eliminate subjects who cannot make the appropriate discriminations. The application of a post-screening method may clarify the tendencies in a test result. However, bearing in mind

1085-806: The time delay would be missing if X was really A and present if X was really B. This extraneous cue was removed by inserting a fixed length dropout time when any change was made. The dropout time was selected to be 50 ms which produces a slight consistent click while allowing subjectively instant comparison. The ABX company is now defunct and hardware comparators in general as commercial offerings extinct. Myriad of software tools exist such as Foobar ABX plug-in for performing file comparisons. But hardware equipment testing requires building custom implementations. ABX test equipment utilizing relays to switch between two different hardware paths can help determine if there are perceptual differences in cables and components. Video, audio and digital transmission paths can be compared. If

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1120-415: The variability of subjects’ sensitivities to different artefacts, caution should be exercised. Other flaws include lack of subject training and familiarization with the test and content selected: 4.1 Familiarization or training phase Prior to formal grading, subjects must be allowed to become thoroughly familiar with the test facilities, the test environment, the grading process, the grading scales and

1155-448: Was greatly hampered by not having the known A and B available for reference. This was corrected by using three interlocked pushbuttons, A, B, and X. Once an X was selected, it would remain that particular A or B until it was decided to move on to another random selection. However, another problem quickly became obvious. There was always an audible relay transition time delay when switching from A to B. When switching from A to X, however,

1190-603: Was one of the first licensees of the MediaLink networking technology developed by the Lone Wolf Corp. for professional audio systems. MediaLink, however, did not prove robust enough for professional audio users, so by the mid 1990s QSC abandoned it in favor of Ethernet-based networking, which was becoming more affordable and ubiquitous. At about the same time, QSC licensed CobraNet technology from Peak Audio to develop products that would distribute multiple channels of audio signals in

1225-558: Was the hardware ABX comparator in 1977, built by the ABX company in Troy, Michigan, and documented by one of its founders, David Clark. Refinements to the A/B test The author's first experience with double-blind audibility testing was as a member of the SMWTMS Audio Club in early 1977. A button was provided which would select at random component A or B. Identifying one of these, the X component

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