(b Rosshaupten, nr Füssen, 4 Nov 1704; d Füssen, 24 April 1773). German organ builder. Known as ‘Orglmacher zu Füessen’ since 1733, he built six organs for churches in that town: St Sebastian (two organs, 1734 and 1772; the first was moved to the Spitalkirche in 1772); the Franciscan church (1735); St Mang (1753–4; great organ and chancel organ); and Frauenkirche am Berg (1773–4; probably completed by Anton Weyrather). In Swabia and Upper Bavaria he built organs in Hindelang (1749); Murnau (1749); Altstädten (1760); and Benediktbeuren (1771). He was also active in the Tyrol, building organs for Kappl (1737); Fliess (1739); the Spitalkirche, Latsch (1741); the Franciscan church, Schwaz (1756; rebuilding); the Cistercian abbey, Stams (1757; chancel organ); the parish church, Stams (c1757); Ischgl (1758–9); the Servite church, Innsbruck (1760); the Franciscan church, Hall (1761); the Benedictine abbey, Fiecht (1772); the Spitalkirche, Innsbruck (1764); the parish church, Bolzano (1764–6); the Spitalkirche, Bolzano (1768); and the Franciscan church, Reutte (1769). The specifications of Jäger’s organs include rich choruses, stopped diapasons and flutes (the wooden 4' flutes often being stopped), and strings of a narrow scale. In his larger instruments he also made use of reeds, thus showing his taste for colourful sounds. The two organs of St Mang, Füssen, are especially remarkable both for their outer appearance and their inner structures. The front of the main organ embraces the windows of the west façade, like the Gabler organ in Weingarten. The chancel organ has a low, closed case without any front pipes; most of the wooden pipes are arranged horizontally. For the Pedal chests of the Benediktbeuren organ, Jäger employed a special construction of his own invention: an early type of ventil-chest.