Around 1930, stereo was invented independently by Bell Labs in the USA and by Alan D. Blumlein at EMI Labs in England...
It has frequently been asserted that Mahler asked the oboe to play impossible glissandi or slides. It is true that they are not practicable on the modern instrument, but this was not the instrument that Mahler wrote for. He wrote for the Viennese oboe which, being differently constructed, not only sounds different from the French-style oboe in common use today, but is quite capable of the glissandi that Mahler notated, for instance, in the fourth movement of his Third Symphony.
These glissandi were demonstrated by Klaus-Diether Lienbacher, former oboist of the Vienna Symphony Orchestra, on a Stecher oboe at the conference on the musical instruments and style of playing in Mahler's time, which took place in the Eroicasaal of the Palais Lobkowitz in Vienna in April 2005. This demonstration was recorded and can be heard on the CD accompanying the proceedings of the conference published by the International Gustav Mahler Society and the University of Vienna (Böhlau Verlag).
Mahler's instructions to the player are : ‘hinaufziehen – wie ein Naturlaut’ (pull up – like a sound of nature).
Gustav Mahler Symphony No. 3, 4th mvt. bars 32–34 & 133–137
Rev. 12 Dec 2018