{"@context":"http://iiif.io/api/presentation/3/context.json","id":"https://arsc.aviaryplatform.com/iiif/p26pz53758/manifest","type":"Manifest","label":{"en":["The Columbia LP Equalization Curve"]},"logo":"https://d9jk7wjtjpu5g.cloudfront.net/organizations/logo_images/000/000/019/original/ARSC_Full_Logo_RGB_K.jpg?1605438091","metadata":[{"label":{"en":["Agent"]},"value":{"en":["Gary A. Galo (Presenter)"]}},{"label":{"en":["Date"]},"value":{"en":["2008-03-29 (Created)"]}},{"label":{"en":["Format"]},"value":{"en":["Audio"]}},{"label":{"en":["Description"]},"value":{"en":["\u003cp\u003eIn 1948 Columbia introduced the microgroove long-playing record. At that time, the RIAA LP equalization curve – which would eventually supersede the Columbia curve – had not even been proposed, much less standardized, and the equalization curve chosen by Columbia differed from RIAA in both the low-bass turnover and the treble roll-off. In developing a design for an archival phono preamplifier, the author found a number of conflicting opinions regarding the Columbia LP equalization curve. The answer was found in a paper published in the Proceedings of the I.R.E. by René Snepvangers in August, 1949. Snepvangers, the unheralded primary inventor of the Columbia LP, provided a graph illustrating how the Columbia LP curve had been derived from the NAB equalization curve used for 16-inch, 33 1/3-rpm lacquer discs. Unfortunately, SnepvangersÕ graph was not accompanied by any data on either the turnover frequencies or time constants. Through computerized circuit simulations, the author was able to determine, definitively, the time constants and frequencies of the low-bass shelf, the bass turnover, and the treble pre-emphasis. This presentation will provide an analysis of Snepvangers' graph, and describe the process by which the time constants and turnover frequencies were determined. The results leave little room for doubt regarding the recording characteristic of the Columbia LP, and the playback curve required for correct reproduction.\u003c/p\u003e"]}},{"label":{"en":["Language"]},"value":{"en":["English"]}},{"label":{"en":["Publisher"]},"value":{"en":["Association for Recorded Sound Collections"]}},{"label":{"en":["Rights Statement"]},"value":{"en":["\u003cp\u003eCopyright Association for Recorded Sound Collections\u003c/p\u003e"]}}],"summary":{"en":["\u003cp\u003eIn 1948 Columbia introduced the microgroove long-playing record. At that time, the RIAA LP equalization curve \u0026ndash; which would eventually supersede the Columbia curve \u0026ndash; had not even been proposed, much less standardized, and the equalization curve chosen by Columbia differed from RIAA in both the low-bass turnover and the treble roll-off. In developing a design for an archival phono preamplifier, the author found a number of conflicting opinions regarding the Columbia LP equalization curve. The answer was found in a paper published in the Proceedings of the I.R.E. by Ren\u0026eacute; Snepvangers in August, 1949. Snepvangers, the unheralded primary inventor of the Columbia LP, provided a graph illustrating how the Columbia LP curve had been derived from the NAB equalization curve used for 16-inch, 33 1/3-rpm lacquer discs. Unfortunately, Snepvangers\u0026Otilde; graph was not accompanied by any data on either the turnover frequencies or time constants. Through computerized circuit simulations, the author was able to determine, definitively, the time constants and frequencies of the low-bass shelf, the bass turnover, and the treble pre-emphasis. This presentation will provide an analysis of Snepvangers' graph, and describe the process by which the time constants and turnover frequencies were determined. The results leave little room for doubt regarding the recording characteristic of the Columbia LP, and the playback curve required for correct reproduction.\u003c/p\u003e"]},"requiredStatement":{"label":{"en":["Attribution"]},"value":{"en":["\u003cp\u003eCopyright Association for Recorded Sound Collections\u003c/p\u003e"]}},"provider":[{"id":"https://arsc.aviaryplatform.com/aboutus","type":"Agent","label":{"en":["Association for Recorded Sound Collections"]},"homepage":[{"id":"https://arsc.aviaryplatform.com/","type":"Text","label":{"en":["Association for Recorded Sound Collections"]},"format":"text/html"}],"logo":[{"id":"https://d9jk7wjtjpu5g.cloudfront.net/organizations/logo_images/000/000/019/original/ARSC_Full_Logo_RGB_K.jpg?1605438091","type":"Image"}]}],"thumbnail":[{"id":"https://d9jk7wjtjpu5g.cloudfront.net/public/images/audio-default.png","type":"Image","format":"image/png"}],"items":[{"id":"https://arsc.aviaryplatform.com/collections/2672/collection_resources/128624/file/240128","type":"Canvas","label":{"en":["Media File 1 of 1 - open-uri20240504-2220384-69sjbs.mpga"]},"duration":2266.9925,"width":640,"height":360,"thumbnail":[{"id":"https://d9jk7wjtjpu5g.cloudfront.net/public/images/audio-default.png","type":"Image","format":"image/png"}],"items":[{"id":"https://arsc.aviaryplatform.com/collections/2672/collection_resources/128624/file/240128/content/1","type":"AnnotationPage","items":[{"id":"https://arsc.aviaryplatform.com/collections/2672/collection_resources/128624/file/240128/content/1/annotation/1","type":"Annotation","motivation":"painting","body":{"id":"https://aviary-p-arsc.s3.wasabisys.com/collection_resource_files/resource_files/000/240/128/original/open-uri20240504-2220384-69sjbs.mpga?1714790414","type":"Audio","format":"audio/mpeg","duration":2266.9925,"width":640,"height":360},"target":"https://arsc.aviaryplatform.com/collections/2672/collection_resources/128624/file/240128","metadata":[]}]}],"annotations":[]}]}