What Ever Happened to Quadraphonic Sound?

Buying a Quadraphonic Sansui receiver spurred me to reacquaint myself and learn about the whole quad thing. Is it cool? Is it just a gimmick? I explore it all in only nine minutes. I have a Patreon page available if you are interested in supporting my channel:   / myowndevices   Best Hi-Fi Speakers High-End Audio Gear Audiophile Music Collection Hi-Fi System Setup Top Audio Amplifiers Hi-Fi Speaker Reviews Vinyl Record Collection Hi-Fi Equipment Showcase Audiophile Headphones Hi-Res Audio Players Hi-Fi Tube Amplifiers Best DACs for Audiophiles Hi-Fi Stereo Sound Turntable Setup Tips Audiophile Listening Room High-Fidelity Audio Cables Vintage Hi-Fi Gear Hi-Fi Tweaks and Upgrades Audiophile Jazz Recordings Hi-Fi Audio Demos Audiophile Classical Music Hi-Fi Speaker Comparisons High-End Audio Brands Hi-Fi Audio Streaming Audiophile Power Conditioners Hi-Fi Audio DIY Projects Audiophile Vocal Recordings Hi-Fi Speaker Placement Best Hi-Fi Integrated Amplifiers Audiophile Electronic Music Hi-Fi Audio Shows and Events Audiophile Hi-Fi Unboxings Hi-Fi Stereo Receiver Reviews Audiophile Acoustic Treatments Best audiophile DAC Hi-Fi Audio Product Comparisons Audiophile Blues Recordings Hi-Fi System Buying Guide Hi-Fi Speaker Shootouts Audiophile Live Music Recordings Hi-Fi Audio Restoration Tips Best Hi-Fi Bookshelf Speakers Audiophile Rock Music Collection Hi-Fi Audio Calibration Techniques Audiophile Soundtrack Recordings Hi-Fi Amplifier Class Comparisons Audiophile World Music Selections Hi-Fi Speaker Cable Upgrades Audiophile Bass Recordings Hi-Fi Audio Room Acoustics