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Topic: Equal-loudness contour

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Equal-loudness contour - Wikipedia, the free encyclopedia The lowest equal loudness contour represents the quietest audible tone and is also known as the absolute threshold of hearing. The unit of measurement for loudness levels is the phon, and by definition two sine waves that have equal phons are equally loud. Loudness, being a psychological quantity, is difficult to measure, so Fletcher and Munson averaged their results over many test subjects to derive reasonable averages. en.wikipedia.org /wiki/Equal-loudness_contour   (848 words)

Phon - Wikipedia, the free encyclopedia At other frequencies, the phon departs from the decibel, but is related to it by a frequency weighting curve (equal-loudness contour) that reflects the frequency response of human hearing. The standard curve for human hearing is the A-weighted curve (the equal-loudness contour for a 40 dB stimulus at 1 kHz), but others are in use. The phon is a unit of perceived loudness, which is a subjective measure of the strength (not intensity) of a sound. en.wikipedia.org /?title=Phon   (243 words)

YourArt.com >> Encyclopedia >> decibel The most widely used frequency weighting is the "A-weighting", which roughly corresponds to the inverse of the 40 dB (at 1 kHz) equal-loudness curve. Since the human ear is not equally sensitive to all the frequencies of sound within the entire spectrum, noise levels at maximum human sensitivity — middle A and its higher harmonics (between 2 and 4 kHz) — are factored more heavily into sound descriptions using a process called frequency weighting. The decibel is widely used in measurements of the loudness of sound. www.yourart.com /research/encyclopedia.cgi?subject=/decibel   (3851 words)

Sound Quality Glossary Terms Equal loudness contour: A contour representing a constant loudness for all audible frequencies. The contour having a sound pressure level of 40 dB at 1,000Hz is arbitrarily defined as the 40-phon contour. Listening to many equally "good" speakers will reveal that some sound warmer than others, some sound brighter etc. In a surround sound system it is important that all speakers have a close timbral match for the highest degree of sonic realism. www.owenscorning.com /around/sound/glossary.asp   (7146 words)

Phon - the free encyclopedia A-weighted curve (the equal-loudness contour for a 40 dB stimulus at 1 kHz), but others are in use. kHz, 1 phon is defined to be equal to 1 dB of The standard curve for human hearing is the www.free-web-encyclopedia.com /?t=Phon   (120 words)

E2S Knowledge Base - Sound Pressure Level - SPL One reason for this lack of correlation is because the equal loudness contours where based on experiments which used pure tones where most common sounds are in fact very complex signals. The 'A' weighting network weights a signal in a manner which approximates to an inverted equal loudness contour at low SPL's, the 'B' network corresponds to a contour at medium SPL's and the 'C' network to an equal loudness contour at high SPL's. It is generally agreed that the perceived loudness of sounds shorter than 70 milliseconds is less than that of sounds of longer durations having the same level. www.e-2-s.com /kb-3.htm   (359 words)

Automatic loudness controller - Patent 4406923 Apparatus according to claim 3, wherein the loudness analyzing means has a transfer function proportional to a 70 phon equal loudness contour representative of the loudness levels of broadcasting sounds as a function of frequency and intensity over a range of pressure levels from about 60 db to about 80 db. 2, and of the transfer function of the loudness contour used in the apparatus of FIG. To explain, if a low-loudness, high-level signal were presented to a loudness controller which had no form of level control, the controller would increase gain as much as necessary to bring the signal up to the correct loudness level; the resultant increase in level would probably overdrive the peak limiter at the transmitter. www.freepatentsonline.com /4406923.html   (3340 words)

Noise 2pl The phon is defined as the sound level due to a sound pressure of 0.0002 microbars at 1000 Hz, which creates equal loudness in the ear for all frequencies (pure tones). To make measurements of sound pressure meaningful equal loudness curves have been derived, and the unit is the "phon". A loudness curve for 40 phons (column 2 of table 3.2.1) would therefore be a curve for 40 Db above the threshold of hearing, regardless of sound frequency. metp02.mw.tu-dresden.de /Merz_McLellan/windenergy/Noise.htm   (1423 words)

Handout Equal Loudness Contours: First devised by Fletcher, and often called the Fletcher/Munson Equal Loudness Contours, this is a graph of the non-linear interaction of frequency and loudness. Since tones at 1,000 Hz were the standard upon which the equal loudness contours were based, dB IL and dB LL (phons) are the same at 1,000 Hz. The curves represent the amount of energy another tone must have to be equally loud to the standard tone. www.ethnomusic.ucla.edu /systematic/Students/Hiro/170Hiro/170Handout.htm   (972 words)

26898.001130&ELEMENT_SET=DECL The equal loudness contours, or similar curves, may be stored in the instrument and employed in calculations by the instrument to determine the desired amplitudes of the blended notes of a played chord when the blending function is selected on the instrument. Such a loudness curve may be, for example, an equal loudness contour based upon the frequency and amplitude of the lowest frequency note in the chord and established by interpolation between curves in Fig. Loudness is the listener's subjective response to the energy and frequency of a note. www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/26898.001130&ELEMENT_SET=DECL   (8956 words)

Ethnomusicology 170: Acoustics Loudness of complex tones is approximated by summing loudness of each excited critical band in sons. The angle of reflection is equal to that of incidence (approach). Loudness in dB cannot be added or subtracted, because it is in log-scale. www.ethnomusic.ucla.edu /systematic/Students/Hiro/170Hiro/Acoustics170_97F.htm   (2075 words)

circle of poets, rythm, poetry, poetry contest, poetry competition Stress or loudness was denoted as primary, secondary, tertiary or weak. Literary critics have equally avoided reality by making a fetish of metrical regularity, recasting poetry in simplistic models that do not explain why poetry was ever written in the first place. Equally varied has been the disposition of the poem on the page. rythm.circleofpoets.com   (7941 words)

Equal_Loudness_Contours The ear is not equally sensitive to all frequencies, particularly in the low and high s that are perceived as being equally loud. Curves based on the studies of Fletcher and Munson showing the response of the human hearing mechanism as a function of frequency and loudness levels. www.sfu.ca /sonic-studio/handbook/Equal_Loudness_Contours.html   (254 words)

elements of effective hearing-aid performance Achievement of this goal would imply that the subject hears speech elements with a relative loudness that is the same as or similar to the loudness heard by normal listeners for those elements.  This has not been proven, but whether or not it is true, previously inaudible speech elements are made audible. Binaural fittings significantly improve speech understanding in noise.  The phenomenon is called binaural release from masking.  Binaural summation of loudness also reduces the SPLs required for a given loudness (usually by about 4 dB for hearing-impaired patients), and thus alleviates the feedback problem. An effective hearing aid should compensate for the perceptive distortions of the patient; it should provide a neutral base (flat insertion gain and low distortion) that doesn't bias the compensation processing; and it should be fitted to the hearing characteristics of the individual patient.  Fulfilling two out of three of these requirements is not enough. www.audiologyonline.com /articles/pf_article_detail.asp?article_id=565   (1247 words)

Equal Loudness Contours These graphs show that the subjective perception of equal loudness over a range of frequencies is variable according to those frequencies. Each line shows the intensity level for the range of frequencies which give a subjective impression of similar loudness in reference to a starting level at 1000 Hertz. If the playback level is too high or too low an unbalanced frequency image is likely to occur particularly in the low frequency range where our perception of loudness changes significantly at various loudness levels. www.sfu.ca /sca/Manuals/ZAAPf/e/equal_loud_cont.html   (155 words)

PsyArt: An Online Journal for the Psychological Study of the Arts. Notwithstanding this equal duration, the /d/ in the reading reflected in Figure 13 is more salient than in those reflected in figure 14, owing to the great contrast between the two syllables, and the separation of loudness chunks within the first syllable, as pointed out above. Having the shape of a terminal contour, it groups the first five positions backwards, away from the second half, dividing the sequence into two halves of equal length but unequal structures. When the same contour is perceived in the performance of a verse line like excerpt 5, at the middle of a sequence of ten alternating weak and strong positions, it cannot indicate a stand-alone dictionary entry, especially when its last consonant is coarticulated with the ensuing preposition. www.clas.ufl.edu /ipsa/journal/2002_tsur05.shtml   (12396 words)

A, B, and C Contour Filters for Sound Measurement This measurement is made with a sound level meter with an A contour filter which provides the best instrument match of the ear's equal loudness curves for soft sounds in the neighborhood of 40 dB. When this filter, (which is one of the standard contour filters of most sound level meters) is used, the levels should be recorded as dBA rather than dB. The A-contour filters out significantly more bass than the others, and is designed to approximate the ear at around the 40 phon level. hyperphysics.phy-astr.gsu.edu /hbase/sound/acont.html   (290 words)

GUIDE: How To Properly Encode Dolby Digital Audio (AC3) - Page 2 - Doom9's Forum Since the equal loudness contour applies a psychoacoustic model to the sound when computing the perceived loudness, you can view the application of this curve as an updated algorithm for computing the RMS power (if you're trying to associate RMS power with perceived loudness). Furthermore, I believe the difference in final measurement with and without equal loudness contour may be well within the tolerance/error that results from using an RMS power measurement rather than LAeq. At any rate, if you don't believe the equal loudness contour should be used or is not applicable to the material, it can be turned off in Sound Forge's normalization dialog box. forum.doom9.org /showthread.php?t=56020&page=2   (2967 words)

Human Ear and Hearing Equal loudness contours show lines of sounds equally loud as a function of frequency. If two sounds, of the same loudness and pitch, are differentiated by our ears, it means that they have their own timbre. Loudness depends on the acoustic pressure, frequency, waveform and duration of sounds. hkusury2.hku.hk /ffng/construction/sonic/concepts/hearing.htm   (328 words)

Local improvement in auditory frequency discrimination is associated with hearing-loss slope in subjects with cochlear damage -- Thai-Van et al. 125 (3): 524 -- Brain The equal-loudness contour was measured referring to a 2000 Hz tone delivered at 30 dB SL, with comparison tones spaced at intervals of 1/2 octave. Each equal-loudness contour was measured referring to a 500 Hz tone delivered at 30 dB SL, with comparison tones spaced at intervals of 1/2 octave. an equal-loudness contour curve measured at 1/2-octave intervals. brain.oxfordjournals.org /cgi/content/full/125/3/524   (6589 words)

Noise guidelines - Chapter 2 There is a family of these equal-loudness contours (ISO 1987a) that describe the frequency response of the hearing system for a wide range of frequencies and sound pressure levels. Thus, not all frequencies are perceived as being equally loud at the same sound pressure level, and when calculating overall environmental noise ratings it is necessary to consider sounds at some frequencies as more important than those at other frequencies. According to the equal energy principle, the effect of a combination of noise events is related to the combined sound energy of those events. www.who.int /docstore/peh/noise/Commnoise2.htm   (8638 words)

Fletcher-Munson Curve Explanation The numbers on each curve identify it in terms of phons, a unit of loudness that compensates for frequency effects. The interesting aspects of these curves are that it is difficult to hear low frequency of soft sounds, and that the ear is extra sensitive between 1 and 6 kilohertz. This is a very difficult judgement to make, and the curves are the average results from many subjects, so they should be considered general indicators rather than a prescription as to what a single individual might hear. www.webervst.com /fm.htm   (171 words)

loudness - OneLook Dictionary Search Phrases that include loudness: binaural alternate loudness balance test, equal loudness contour, loudness level, equal loudness curve, loudness discomfort level, more... Words similar to loudness: brashness, flashiness, garishness, gaudiness, glitz, intensity, meretriciousness, tawdriness, volume, more... Loudness : Online Plain Text English Dictionary [home, info] www.onelook.com /?w=loudness   (219 words)

Hydrogenaudio Forums > Normalize - Soundforge Or Wavegain? ReplayGain ranks the loudness value of the whole song into order from quietest to loudest then takes a value 95 percent of the way along the list, so that 5 percent of the instants were louder than that instant. It sounds like SoundForge may be averaging the loudness of all the short chunks of sound ('instants') and using that as its loudness. You are right, it's impossible reach the same loudness with all files of an album, I little time ago I found that win WavGain I can do this, and applying Hard Limiter in WavGain you can reach the SPL value that you want without clips, e.g. www.hydrogenaudio.org /forums/lofiversion/index.php/t11057.html   (2765 words)

The Interdependence of Loudness and Pitch Thus, all tones that match a 1K Hz tone of a given intensity should all be equally loud and connecting those on a graph of intensity by frequency should give an equal loudness contour. Subjects adjusted tone of different frequencies to match loudness of 1000 Hz tome psych.hanover.edu /Classes/hfnotes/tsld047.html   (57 words)

Perception 3203 - Study Guide 4 Be able to describe/draw an equal loudness contour (and don't forget to label/explain the axes). Be able to describe/draw an equal pitch contour (and don't forget to label/explain the axes). Is the decibel scale a psychological scale of loudness? www.acs.appstate.edu /~kms/classes/psy3203/study4_03.htm   (293 words)

SOUNDING - LoveToKnow Article on SOUNDING If we are to assume that the tones received by the ear are pure and free from partials, the loudness of the beattones would appear to show that Helmholtzs theory is not a complete account. There is not much difficulty in detecting the difference tone by a resonator if it is held, say, close to the reeds of a harmonium, and Helmholtz succeeded in detecting the summation tone by the aid of a resonator. The operation of sounding is readily performed in shallow water by letting down a weight or lead attached to a cord, which is marked off into fathoms by pieces of leather, rag and twine. www.1911ency.org /S/SO/SOUNDING.htm   (3673 words)

Absolute threshold of hearing: Encyclopedia topic Equal-loudness contour (Equal-loudness contour: an equal-loudness contour, also called a loudness level contour or a fletcher-munson... [follow hyperlink for more...]) represents the lowest curve amongst the set of equal-loudness contour (equal-loudness contour: an equal-loudness contour, also called a loudness level contour or a fletcher-munson... Sone (Sone: A unit of perceived loudness equal to the loudness of a 1000-hertz tone at 40 dB above threshold) www.absoluteastronomy.com /reference/absolute_threshold_of_hearing   (378 words)

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