Monochord
A monochord, also known as sonometer[citation needed] (see below), is an ancient musical and scientific laboratory instrument, involving one (mono-) string (chord)."With its single string, movable bridge and graduated rule, the monochord (kanōn [Greek: law]) straddled the gap between notes and numbers, intervals and ratios, sense-perception and mathematical reason.Many contemporary composers focused on microtonality and just intonation such as Harry Partch, Ivor Darreg, Tony Conrad, Glenn Branca, Bart Hopkin, and Yuri Landman constructed multistring variants of sonometers with movable bridges."[9] The psalmodicon, a similar instrument but with a chromatic fret board replacing the moveable bridge, was developed in Denmark in the 1820s and became widespread throughout Scandinavia in churches as an alternative to the organ.An image of the celestial monochord was used on the 1952 cover of Anthology of American Folk Music by Harry Everett Smith and in the 1977 book The Cosmographical Glass: Renaissance Diagrams of the Universe (p. 133) by S. K. Heninger Jr., ISBN 978-0-87328-208-6.A reproduction of the monochordum mundanum (mundane monochord) illustration from page 90 of Robert Fludd's "Utriusque Cosmi, Maioris scilicet et Minoris, Metaphysica, Physica, Atque Technica Historia" ("Tomus Primus"), 1617, was used as the cover art for Kepler Quartet's 2011 audio CD, Ben Johnston: String Quartets Nos.80693), which is classical music that uses pitch ratios extended to higher partials beyond the standard Pythagorean tuning system.This test, called an ultrasound bone densitometry screening, is not typically used for diagnostic purposes; it is generally used as a risk assessment tool.
Polychordfreely moving wheelmusicallaboratory instrumentmusical bowsHornbostel–Sachsstoppedstringbridgesfrequenciesgraduatedintervalsratiosastronomycourse (music)Mersenne's lawspluckedoctavePythagorean tuningsuperparticulartetractysmultiplication tableleast common multiplescomposite numbers[consonance and dissonance]coursemandolinmajor thirdminor thirdmicrotonalityjust intonationHarry PartchIvor DarregTony ConradGlenn BrancaBart HopkinYuri Landmantuning pegresonating boxend pindan bauhurdy-gurdyclavichordpitchesEnd correctionBishop TheobaldBoethiusSumerianPythagorasGuido of ArezzoRobert FluddPtolemaicpsalmodiconAnthology of American Folk MusicHarry Everett SmithBen JohnstonNew World Recordsexperimental rockcontemporary classical music3rd bridgeEncyclopædia BritannicaBeat (acoustics)Long-string instrumentAcousticsAcoustical engineeringArchitectural acousticsReverberationSoundproofingString vibrationSympathetic resonanceSpectrogramPsychoacousticsBark scaleMel scaleEqual-loudness contourFletcher–Munson curvesAudio frequencyFormantFundamental frequencyFrequency spectrumharmonic spectrumHarmonicSeriesInharmonicityMissing fundamentalCombination toneOvertoneResonanceStanding waveSubharmonicJohn BackusJens BlauertErnst ChladniHermann von HelmholtzCarleen HutchinsFranz MeldeMarin MersenneWerner Meyer-EpplerLord RayleighJoseph SauveurD. Van HollidayThomas YoungInfrasoundUltrasoundMusical acousticsViolinintonationPedal steel guitarTromboneTimpaniHuman voiceSynthesizerWind instrumentsBagpipesNatural hornTromba marinaHarmonicaKeyboard instrumentsSplit sharpFlageolet tonesovertone seriesĐàn bầuPencilinaMoodswingerstringsinstruments