QSound Labs · 1993 · 1990s · 16 voices
QSound was a positional-audio digital signal processor that let Capcom's CPS-2 arcade board place sounds in a wide stereo field, giving Super Street Fighter II and the Darkstalkers series their spacious, enveloping sound.
QSound was not a synthesiser but a psychoacoustic processing algorithm developed by the Canadian firm QSound Labs. It took multiple mono sound sources and, by precisely manipulating timing, amplitude, and frequency response between the left and right outputs, created the illusion that sounds originated from points across a stereo field far wider than the speakers themselves — a binaural trick that exploits how the human head shadows and delays sound reaching the farther ear. Capcom licensed the technology for its CPS-2 hardware, where a dedicated DSP mixed sixteen channels of PCM samples through the QSound algorithm. The result made CPS-2 titles instantly recognisable: the crowd noise, hit impacts, and voices in Super Street Fighter II Turbo, Darkstalkers, and the Marvel vs. Capcom crossovers seemed to surround the player at the cabinet. QSound Labs later refined the process into "Q1", "Q2" for headphones, and multi-speaker "Q3D", but its arcade heyday is inseparable from Capcom's 2D fighting-game golden age.