Editing ZX Spectrum (section)

=== Sound ===
Sound output is produced through a built-in beeper capable of generating a single channel with ten octaves.{{sfn|Wilkins|2015b|p=16}} It is controlled by a single {{code|EAR}} bit.<ref name="worldofspectrum-16-48">{{Cite book |title= 16K / 48K ZX Spectrum Reference |chapter-url= https://worldofspectrum.org/faq/reference/48kreference.htm#PortFE |publisher=  |chapter= PortFE |access-date= 4 July 2023 |archive-date= 25 March 2023 |archive-url= https://web.archive.org/web/20230325133729/https://worldofspectrum.org/faq/reference/48kreference.htm#PortFE |url-status= live }}</ref> By toggling it on and off, simple sounds are generated. This speaker, capable of producing just one note at a time, was governed by the [[BASIC]] command 'BEEP', where programmers could manipulate parameters for pitch and duration.{{sfn|Wilkins|2015a|p=16}} Furthermore, the processor remained occupied exclusively with the BASIC BEEPs until their completion, limiting concurrent operations. Despite these constraints, it marked a significant step forward from the [[ZX81]], which lacked any sound capabilities. Resourceful programmers swiftly devised workarounds; its rudimentary audio functionality compelled developers to explore unconventional methods such as programming the beeper to emit multiple pitches.{{sfn|Wilkins|2015a|p=17}}

Later software became available that allowed for two-channel sound playback. The machine includes an [[expansion bus]] [[edge connector]] and 3.5&nbsp;mm audio in/out ports, facilitating the connection of a [[cassette recorder]] for loading and saving programs and data. The {{code|EAR}} port has a higher output than the {{code|MIC}} and is recommended for headphones, while the {{code|MIC}} port is intended for attachment to other audio devices as a [[line level|line-in]] source.<ref name="Vickers-19">{{Cite book |last= Vickers |first= Steven |title= Sinclair ZX Spectrum BASIC Programming |chapter-url= http://www.worldofspectrum.org/ZXBasicManual/zxmanchap19.html |publisher= [[Sinclair Research Ltd]] |chapter= BEEP |url-status= live |archive-url= https://web.archive.org/web/20141113055815/http://www.worldofspectrum.org/ZXBasicManual/zxmanchap19.html |archive-date= 13 November 2014 }}</ref>