Atari 400/800/XL/XE - Cassette Dual Track system - Kingdom [ATARI] 1880

"The Atari 8-bit Cassette Data Recorders was Dual Track systems
and could load data while also playing audio/music tracks simultaneously.
This meant that while another section of a program was loading,
the recorder could give the palyer instructions, information or play a soundtrack to entertain the player time while the program loaded. " (Atarimuseum.com)
Here is an example with Kindom from ATARI in 1984.
The broken Atari logo bug on the loading screen is not present on Atari 400/800 (BASIC rev.A).
Recorded with Cloner Alliance Box Pro from a real Atari 600 XL (PAL) + Atari 1064 memory module + Atari XC11 cassette data recorder.