Kalaš's voice is preserved on a large number of recordings made on the Ultraphon, Esta, Bruno, Multisonic, and Urania labels.

[1] In 1934 Kalaš succeeded in landing a contract with the Slovak National Theatre in Bratislava, where he began to assail mainly roles from the standard Czech repertoire like Kecal in Bedřich Smetana's The Bartered Bride and the High priest in Antonín Dvořák's Vanda.

Renowned conductor Václav Talich attended several of his performances at the theatre and, impressed with the young bass, poached him for the National Theater in Prague.

[1] Kalaš made his debut at the Prague National Theatre (PNT) as Kecal inn 1939 and became, along with Eduard Haken, one of the house's most important basses during the 1940 and 1950s.

He notably toured with the PNT to Russia, Germany, and Belgium, appearing at such houses as the Bolshoi Theatre (1955), the Berlin State Opera (1956), and La Monnaie (1958).