It's a common misconception that ZX Spectrum 48K sound is generated solely by the Z80 chip, with the AY chip only being used by the more high-tech 128K models. This is not true. The first AY interfaces for 48K Speccys appeared around 1990. FREAKuencies was written entirely on the ZX Spectrum 48K (more specifically a Timex Computer 2048 - the American/Portuguese ZX48K clone) with AY interface. Sound-Tracker 1.1, a Polish music editor made especially for such configuration was used to create these chiptunes on a computer not much bigger than a calculator. Class is over, now go enjoy!