Ultra Son
From CPCWiki - THE Amstrad CPC encyclopedia!
Ultra Son is software which enables to reproduce vocal and musical data, thanks to the Cassette driver.
The data can be then used in your basic or assembler programs or without the software.
Ultra Son was developed in 1988 by Ludovic Deplanque and Stephane Saint-Martin, and was released by MBC.
Because it uses the Cassette reader, it cannot be used by a 6128+, unless this one is modified.