The little-known Schmidt was a pupil of Bruckner, and his symphonies form an apt tribute to his Master. Too, Schmidt lived in the Viennese mileu of Brahms, Mahler, Zemlinsky, Berg, and Korngold. He did not follow Schönberg's lead into dodecaphonism; his ethos is more closely related to Strauss and Reger.
It is tempting to see Schmidt's chamber music as that of late-Bruckner--left unwritten. While there may be a grain of insight to this view, Schmidt has his own sound. He had a preference of major keys, and his outlook is rather enthusiastic and optimistic.
His two String Quartets follow Bruckner's symphonies in placing the heart of the work--substantial Adagios--in movement II--(as in fact, Bruckner had originally intended to do in his own Quintet). Both Quartets are large works of ~:40mins a piece. Schmidt also wrote some Quintets for various ensembles with piano and clarinet.
Interested parties should see also the Quartets of William Kienzl, Karl Weigl, and Joseph Marx, not to mention those of Reger, Zemilnsky, and Korngold.
Wilhelm Kienzl: String Quartets 1-3
Karl Weigl: String Quartets 1 & 5 / Artis Quartett Wien
Joseph Marx: Complete String Quartets
Reger: The String Quartets; Clarinet Quintet
Zemlinsky: The String Quartets / Apostel: String Quartet No. 1
Korngold: String Quartets Nos. 1 & 3
Korngold: String Quartet No. 1; Reznicek: String Quartet No. 1
String Quartet & Quintet
Robert Fuchs: Complete String Quartets
Hindemith: Complete String Quartets