For those who closely follow immersive music releases, one of the most interesting trends over the last several years has been the celebration and reissue of quadraphonic music from the 1970s. Hundreds of popular albums were remixed in this four-channel surround sound format throughout the early-to-mid ‘70s, but consumers ultimately rejected the technology due to the cost of the extra equipment and confusion over competing incompatible vinyl formats.
However, a not-insignificant number of these recordings have since been reissued on high-resolution optical media such as Super Audio CD or Blu-Ray. During the late-1990s and early-2000s, some vintage quad mixes were covertly released as part of Mobile Fidelity International’s ‘High Definition Surround’ series of DTS-encoded CDs and then as part of Sony’s short-lived run of a single layer multichannel SACDs. Key examples include Paul McCartney & Wings’ Band on The Run, The Moody Blues’ Seventh Sojourn, Herbie Hancock’s Head Hunters, and The O’Jays’ Ship Ahoy.
In 2010, following the death of their high-resolution 5.1 surround DVD-Audio format, Rhino–Warner Records' catalog division–surprised audiophiles by issuing a limited-run ‘Quadio’ DVD edition of Chicago’s classic 1969 debut album, Chicago Transit Authority, containing a newly-remastered digital transfer of the 1974 quadraphonic mix. Though this reissue was likely meant to mark the start of an ongoing series, only one more entry ultimately followed (The Best Of Aretha Franklin).
Editor’s Note: Both released in 2010, Chicago Transit Authority and The Best Of Aretha Franklin were the first Quadio products. The series has since moved from DVD to Blu-Ray, starting with 2016’s Chicago Quadio box set.
Things remained quiet until June 2016, when the Chicago Quadio box set–containing nine(!) Blu-Ray discs with the band’s entire quadraphonic output remastered in 192-khz/24-bit DTS-HD Master Audio–appeared out of nowhere. In September 2020, a similar box set followed containing The Doobie Brothers’ four quadraphonic albums on Blu-Ray. September 2017’s Doors: The Singles three-disc set could also be considered a Quadio release, as it contained a Blu-Ray featuring the 1973 Best of The Doors quadraphonic mix originally issued on quad LP, 8-track cartridge, and reel-to-reel.
The full Quadio revival began in the summer of 2023, with the following four titles: Alice Cooper’s Billion Dollar Babies (1974), The J. Geils Band’s Nightmares…And Other Tales From The Vinyl Jungle (1974), Jefferson Starship’s Red Octopus (1975), and Black Sabbath’s Paranoid (1970). Since then, a new batch of four Quadio Blu-Rays has become available every quarter–bringing the total up to 24(!) standalone releases so far, plus associated physical editions like the Joni Mitchell’s The Asylum Albums 1972-75 box set containing both quad and Dolby Atmos mixes. For this article, I thought it’d be interesting to break down some highlights in the series so far–and perhaps also speculate on what may be yet to come.
There seems to be a consensus in some audiophile circles that ‘70s quad mixes tended to be something of an afterthought, similar to the uber-wide stereo mixes of the early Beatles albums that were created largely without the band’s input. As a longtime collector of vintage quadraphonic albums and equipment, it’s my hope that these new reissues from Rhino finally dispel that notion once and for all. The sonic issues that plagued quad LP and tape formats (compromised channel separation, limited high-frequency response, speed warble, etc) are no longer present with Blu-Ray disc, allowing listeners to hear exactly what the mixing engineers heard in the studio five decades ago.
Editor's Note: Most of the Quadio titles released thus far fall under the Warner/Elektra/Atlantic (WEA) umbrella. Whereas most labels that issued quadraphonic product on vinyl utilized a ‘matrix’ process–which yielded imperfect separation between the front and rear channels–WEA had instead adopted the far more sophisticated ‘CD-4’ (Compatible Discrete-4) system for their four-channel LP releases.
Originally developed by JVC in Japan, the CD-4 process entailed hiding the rear channel audio information in a super high-frequency band beyond the range of human hearing. To properly play back a CD-4 LP (often called ‘Quadradiscs’ by the labels), one would have to purchase a special phono cartridge capable of retrieving these very high frequencies as well as an external preamp/decoding device called the ‘disc demodulator’ (pictured above).
Though CD-4 was certainly capable of performance rivaling any of the matrix systems (including CBS’ ‘SQ’ and Sansui’s ‘QS’ processes), the format was plagued by a multitude of issues including an arduous user calibration process and temperamental bouts of distortion. In the United States, both WEA and RCA would both cease production of Quadradiscs by the end of 1975.
Black Sabbath - Paranoid (June 2023)
Though Black Sabbath’s classic second studio LP Paranoid was originally released in September 1970, the quadraphonic version–mixed by Mike Butcher at Morgan Studios in London–wasn’t issued until 1974. To this day, it remains the only Sabbath album to have received a surround/immersive mix–which is especially disappointing given Steven Wilson’s involvement in the recent Vol. 4 (1972) and Technical Ecstasy (1976) super deluxe reissues.
Butcher’s quad mix–while perhaps a bit ‘gimmicky’ by today’s standards, with its copious use of panning and swirling effects–does open up the album in an effective manner, separating out a lot of Tony Iommi’s guitar work and percussion into the rear speakers. “War Pigs” features Bill Ward’s thunderous drumming crashing all around the room, while Ozzy Osbourne’s unmistakable vocals fill up all channels.
Fans may recall that Sanctuary Records in the UK issued a CD/DVD deluxe edition of Paranoid way back in 2009, with the quadraphonic mix included on the DVD. Unfortunately, it appeared to have been sourced from a needle-drop of the quad LP rather than the 15 IPS four-channel master or even a 7.5 IPS consumer tape copy. This ignited speculation in audiophile circles that the quad master may have been lost or unavailable, but the new Quadio Blu-Ray reveals that it’s been in safe hands all along.
Editor’s Note: Paranoid was part of Quadio bundle #1, which also contains Alice Cooper’s Billion Dollar Babies, The J. Geils Band’s Nightmares…And Other Tales From The Vinyl Jungle, and Jefferson Starship’s Red Octopus.
Support IAA by purchasing the Paranoid Quadio via this link!
Read our full review of the Paranoid Quadio here!
America - Holiday (October 2023)
Holiday was folk-rock band America’s fourth studio album, originally released in June 1974. By this point, the band had already achieved considerable success with hit songs such as “A Horse with No Name” (from their eponymous 1972 debut album) and “Ventura Highway” (from 1972’s Homecoming). Produced by the legendary George Martin, Holiday spawned two top-10 singles (“Lonely People” and “Tin Man”) and eventually earned a Gold certification from the RIAA in the United States
Holiday was the first of two quadraphonic releases from America, the second being its 1975 follow-up Hearts (which contained the classic track “Sister Golden Hair”). Homecoming later received an excellent 5.1 surround mix from Elliot Scheiner, which was released on DVD-Audio in 2001. Though the quadraphonic version of Hearts was reissued on Super Audio CD by Audio Fidelity back in 2015, the new Quadio Blu-Ray edition of Holiday marks the first official release of the four-channel mix since 1974.
For me, the quadraphonic mix of Holiday was approached in a relatively conservative yet tasteful fashion. “Tin Man” starts off as stereo just in the front channels, but additional elements like percussion, strings, and backing vocals gently emerge from behind as the arrangement grows more complex. “Lonely People” again surrounds the listener with gorgeous harmony vocals, while the traffic sounds in “Hollywood” swirl all around the room to very cool effect.
Editor’s Note: Holiday was part of Quadio bundle #2, which also contains Gordon Lightfoot’s Sundown, Charles Mingus’ Mingus Moves, and The Spinners’ self-titled debut album.
Support IAA by purchasing the Holiday Quadio via this link!
War - The World Is A Ghetto (February 2024)
Originally released in 1972 through United Artists records, War’s fifth studio LP The World Is A Ghetto received critical and commercial acclaim–spawning two hit singles in the “The Cisco Kid” and the title track. During the ‘70s, a quadraphonic mix of the album was released exclusively on 8-track cartridge. United Artists released a handful of key titles from their back-catalog in quad during this era, including Donald Byrd‘s Black Byrd (get it on SACD from Dutton-Vocalion) and Ike & Tina Turner’s Live at Carnegie Hall. The follow-up record Deliver The Word also received a quad mix, as did the double LP War Live.
Having owned the original white-shell 8-track cartridge, I can attest that the sound quality of the quadraphonic mix was truly awful. So with that in mind, the new Quadio Blu-Ray sourced from the original ½-inch 4-track master is a sonic revelation. The four-channel mix is very well-executed, surrounding the listener with all kinds of interesting elements including percussion and harmony vocals. The bass guitar and lead vocals are interestingly placed at equal volume in all four speakers, as if they’re projecting inside the listener’s head.
It will be interesting to see if Rhino sees fit to issue Quadio editions of the following two War releases. Plus, 1975’s Why Can’t We Be Friends? (containing the hit singles “Low Rider” and “Why Can’t We Be Friends?”) was long rumored to have been mixed in quad and left unreleased. If true, a Blu-Ray edition of that album with the long-lost four-channel mix is an especially tantalizing prospect.
Editor’s Note: The World Is A Ghetto was part of Quadio bundle #3, which also contains Average White Band’s AWB, Gil Evans’ Svengali, and Randy Newman’s Good Old Boys.
Support IAA by purchasing The World Is A Ghetto Quadio via this link!
Deep Purple - Machine Head (March 2024)
Originally released through Purple Records in March 1972, Machine Head was the third Deep Purple album to feature the band’s acclaimed ‘mark II’ lineup of Ian Gillian (vocals), Ritchie Blackmore (guitar), Jon Lord (organ), Roger Glover (bass), and Ian Paice (drums). Recorded in Montreux, Switzerland and perhaps best remembered for the classic single “Smoke On The Water” (containing arguably the most recognizable guitar riff of all time), Machine Head went on to become Deep Purple’s most successful studio release and one of the seminal British hard rock albums of the early-1970s.
Though EMI/Purple Records had issued their own quadraphonic edition of the album on SQ-encoded LP and 8-track cartridge in the UK, Europe, and Australia back in 1972, a completely different four-channel mix was prepared for the American market two years later. Much to the excitement of longtime quad fans, the Blu-Ray disc in the 50th anniversary box set contains a digital transfer of this long out-of-print four-channel mix from the original master tape. So for the first time ever, it’s possible to hear the rare US quad mix without any vinyl artifacts, speed warble, or tape hiss.
This quadraphonic mix was approached quite differently than its UK counterpart. Blackmore’s rhythm guitar and Lord’s organ are confined to the front channels (panned hard left and right), with Roger Glover’s bass appearing directly behind the listener’s head. Paice's drums fill up all four channels–the intro to "Pictures of Home" in particular sounds absolutely massive–while solos tend to pop out of the rear speakers as well.
Support IAA by purchasing the Machine Head 50th Anniversary box set via this link!
Read our full review of the Machine Head 50th Anniversary box set here!
Joni Mitchell - Miles of Aisles (April 2024)
Joni Mitchell’s The Asylum Albums 1972-75 (Quadio) four-disc box set unexpectedly arrived in April 2024, compiling four of the most popular entries in Mitchell’s discography: 1972’s For The Roses, 1974’s Court and Spark, the 1974 live double LP Miles of Aisles, and finally 1975’s The Hissing of Summer Lawns. The set houses four audio-only Blu-Ray discs–each containing not only the excellent Ken Caillat/Claus Trelby Dolby Atmos mixes released to streaming services in 2022, but also 192-khz/24-bit digital transfers of the rare quadraphonic mixes from the ‘70s.
As many longtime immersive music fans may recall, Asylum Records issued both Court and Spark and The Hissing of Summer Lawns on quadraphonic LP and 8-track cartridge. Though quad LP and tape editions of Miles of Aisles–the live album that came out between Court and Hissing–never materialized, it turns out that a four-channel mix was indeed prepared by engineer Henry Lewy and ultimately left unreleased. After having languished in a vault for five decades, this mix finally saw the light of day as part of the new Quadio box set.
Though most surround mixes of live material treat the listener as a member of audience, the quad version of Miles of Aisles instead places you on stage with the L.A. Express. John Guerin’s drums hold down the front stage, with Robben Ford’s electric guitar isolated in the left rear speaker and Larry Nash’s keyboard over in the right rear. Joni Mitchell's voice and Max Bennett’s bass guitar appear omnipresent in all four channels, but additional accents such as the percussion in “Carey” and Tom Scott’s sax in "Cold Blue Steel" are centered in the rear speakers–directly behind the listener’s head–along with the audience noise at the beginning and end of each track.
Read our full review of the The Asylum Albums 1972-75 Quadio box set here!
Seals & Crofts - Summer Breeze (May 2024)
The soft rock duo’s fourth studio album arrived via WB Records in September 1972, marking their commercial breakthrough. Summer Breeze peaked at #7 on the Billboard charts, spawning two hit singles in the title track and “Hummingbird.” The album features a number of top session players, including ace drummer Jim Keltner and The Wrecking Crew’s Larry Knechtel.
Though Summer Breeze was originally released as a stereo LP in 1972, the quadraphonic version didn’t become available until 1974. The duo’s subsequent albums Diamond Girl (1973), Unborn Child (1974), and I'll Play for You (1975) were also issued on quad LP or tape. It remains to be seen whether or not Rhino will issue Quadio editions of those albums as well.
The quadraphonic mix of Summer Breeze veers on the conservative side, but I think it’s tastefully done and faithful to the original stereo release. Strings emanate from the rear in “Hummingbird,” with the rhythm section upfront and vocals omnipresent in all channels. The acoustic intro to the title track percolates mostly from behind to stunning effect, while the piano and flute are placed upfront with the drums.
Editor’s Note: Summer Breeze was part of Quadio bundle #4, which also contains Donny Hathaway’s Extension of a Man, Roberta Flack’s Killing Me Softly, and Hot Tuna’s Burgers (previously only available on 8-track cartridge!).
Support IAA by purchasing the Summer Breeze Quadio via this link!
Bread - Baby I’m A Want You (August 2024)
Bread’s fourth studio LP originally hit shelves in January 1972, released through Elektra Records. The album spawned a whopping four hit singles (“"Mother Freedom," "Baby I'm-a Want You," "Everything I Own," and "Diary"), all of which charted in the Billboard top-40.
Baby I’m A Want You was the David Gates-led group’s second quadraphonic release, following 1973’s The Best of Bread compilation (which was released on SACD by Audio Fidelity back in 2015). Gates’ subsequent solo albums First (1973) and Never Let Her Go (1975) were also issued on quad LP and tape, making them potential candidates for future Quadio Blu-Ray release.
Like nearly all the Elektra quad albums issued on CD-4 vinyl, the multichannel mix makes quite aggressive use of the additional speakers. Drums are frequently placed behind the listener in true ‘70s fashion, while Gates’ vocal floats out towards the center of the room.
Editor’s Note: Baby I’m A Want You was part of Quadio bundle #5, which also contains Bette Midler’s The Divine Miss M, Duke Ellington’s New Orleans Suite, and Graham Central Station’s self-titled debut album.
Support IAA by purchasing the Baby I’m A Want You Quadio via this link!
Carly Simon - No Secrets (August 2024)
Best remembered for the mega-hit “You’re So Vain,” Carly Simon’s breakthrough third studio LP No Secrets arrived via Elektra Records in November 1972. The album was recorded primarily at London’s famous Trident Studios, produced by Richard Perry (Barbra Streisand, Diana Ross, Art Garfunkel, Ringo Starr, etc) and mixed by Bill Schnee (who went on to work with acts such as Steely Dan, Pablo Cruise, and Boz Scaggs later in the decade). Though Simon had already made waves with prior hits like the Grammy-nominated “That’s The Way I’d Always Heard It Should Be” and the title track to 1972’s Anticipation, No Secrets catapulted her to international superstardom.
The album proved so popular that in 1973, it was chosen as one of the inaugural quadraphonic LP releases from Elektra. The quadraphonic version of the album was created by Bill Schnee, who was also responsible for the bulk of the original stereo mixes. The new Blu-Ray Audio edition of No Secrets corrals all three multichannel releases of the classic album: the 1973 quadraphonic version (never before released in a digital format), the out-of-print 2001 5.1 surround mix, and the 2022 Dolby Atmos mix (previously exclusive to streaming services).
The quadraphonic mix of No Secrets isn't just a three-dimensional presentation of the familiar stereo mix, but rather a completely unique interpretation of the album with different balances. For instance, the electric rhythm guitar part throughout “You’re So Vain” protrudes loudly from the right rear speaker–giving the song a harder-rocking edge. There are several other instances of this sort of thing throughout the four-channel version of the album, little deviations that give the music a different flavor.
Support IAA by purchasing the No Secrets Blu-Ray via this link!
Read our full review of the No Secrets Blu-Ray here!
The Doobie Brothers - Toulouse Street (October 2024)
The Doobie Brothers’ seminal second studio LP was originally released in July 1972, produced by Ted Templeman (Van Morrison, Van Halen, etc). Best remembered for the hit singles “Listen to the Music” and “Jesus Is Just Alright," the album was reissued just two years later on CD-4 LP, 8-track cartridge, and reel-to-reel. The group’s subsequent three albums–1973’s The Captain and Me, 1974’s What Were Once Vices Are Now Habits, and 1975’s Stampede–also received four-channel remixes.
All four albums were compiled into September 2020’s Doobie Brothers Quadio box set, which contained four audio-only Blu-Ray discs with 192-khz/24-bit digital transfers of the ½-inch 4-track masters. In October 2024, Toulouse Street was reissued as a standalone disc–allowing fans who missed the box set (which is now out-of-print) to hear the quadraphonic mix in the best quality possible.
“Listen To The Music'' opens with the acoustic guitar in the front right speaker, mirroring the stereo mix, but quickly blasts into full immersion with the bass guitar suspended directly behind the listener’s head. The opening guitar line to “Rockin’ Down The Highway” appears completely isolated in the right rear speaker. There are even a few passages with the lead vocals in the rear, like the middle section of “Jesus Is Just Alright.”
Editor’s Note: Toulouse Street was part of Quadio bundle #6, which also contains Foghat’s Energized (never before released in quad!), The J. Geils Band’s Bloodshot (never before released in quad!) and Jefferson Starship’s Dragon Fly.
Support IAA by purchasing the Toulouse Street Quadio via this link!
Billy Cobham - Spectrum (February 2025)
After performing on dozens of seminal early-70s fusion records such as Miles Davis’ A Tribute to Jack Johnson (1970), the Mahavishnu Orchestra’s Inner Mounting Flame (1971), and Deodato’s Prelude (1972), legendary drummer Billy Cobham released his first solo LP Spectrum through Atlantic records in October 1973. Featuring Jan Hammer on keyboards and Tommy Bolin on guitar, the album proved an unexpected success–reaching #1 on the Billboard Jazz Albums chart and #26 on the Top 200 Albums chart.
Though Spectrum was mixed to quadraphonic during the ‘70s, for reasons unknown it was never released on four-channel LP or tape (though one song, “Quadrant 4,” made it out as part of a European CD-4 sampler LP). When the album was released on DVD-Audio in 2001, the label opted to commission a brand-new 5.1 remix from the original multitrack tapes rather than utilize the existing quad master. The lost four-channel mix was finally unearthed in 2015, when it was released on SACD by Audio Fidelity. The 2025 Quadio Blu-Ray contains both the 2001 5.1 remix and a brand-new 192-khz/24-bit digital transfer of the ½-inch 4-track master.
“Quadrant 4” kicks things off with Cobham’s drums arrayed across the front stage, while Lee Sklar’s bass resides in the front ‘phantom’ center. Bolin’s guitar and Hammer’s keys are isolated in the back corners, to extremely cool effect. Other tracks like “Searching for the Right Door” have the drums filling up all four channels, with tom-tom rolls and cymbal crashes emanating from behind the listener.
Editor’s Note: Spectrum was part of Quadio bundle #7, which also contains Aretha Franklin’s Live At The Fillmore West, Curtis Mayfield’s Roots (previously only available on 8-track cartridge!), and The Spinners’ Pick Of The Litter.
Support IAA by purchasing the Spectrum Quadio via this link!
Chicago - Chicago II (April 2025)
Originally released through Columbia Records in January 1970, Chicago’s self-titled second studio album proved an instant success and is often cited as the group’s breakthrough album. Issued less than a year after their debut Chicago Transit Authority (1969), the double LP spawned three hit singles–”Make Me Smile,” “25 Or 6 To 4,” and “Colour My World”–and quickly earned a gold certification from the RIAA.
The 55th anniversary Blu-Ray Audio edition of Chicago II collects all three surround mixes of the album (1974 quadraphonic, 2003 5.1 surround, and 2025 Dolby Atmos) alongside Wilson’s 2017 stereo mix in 96-khz/24-bit resolution, making it the definitive version of this iconic album.
As was also the case with Rhino’s recent Blu-Ray reissue of Carly Simon’s No Secrets, each of the three multichannel options on the disc present the music in radically different ways. The channel separation in the quadraphonic mix is extreme, perhaps because it was tailored for compatibility with CBS Records’ proprietary SQ matrix process. Key instrumentation like the brass, backing vocals, rhythm guitars, piano, and backing vocals frequently appear entirely isolated in the rear speakers.
Support IAA by purchasing the Chicago II Blu-Ray via this link!
Read our full review of the Chicago II Blu-Ray here!
Rod Stewart - Atlantic Crossing (April 2025)
Atlantic Crossing was Rod Stewart's sixth solo LP, originally released through Warner Brothers records in August 1975. Produced by Tom Dowd, the album contains two of Stewart's most popular hits–"Sailing" and "I Don't Want to Talk About It”–alongside a myriad of other memorable covers such as "Drift Away" and "This Old Heart of Mine." Side 1, the 'fast side,' contains the harder-rocking tracks, while side 2 is reserved for the ballads.
Though Atlantic Crossing was never issued on quad LP or tape, the team at Rhino have miraculously managed to unearth a lost ½-inch 4-track master prepared by Tom Dowd ostensibly for an aborted CD-4 vinyl release. It's a real shame this mix sat on the shelf for nearly five decades, as it's excellent and feels almost as refined as a modern 5.1 at times. The rear speakers are used quite extensively for key instrumentation like the rhythm guitars, keys, orchestration, and backing vocals.
"Three Time Loser" sets the template for the four-channel experience, with the dueling rhythm guitars chugging in the back corners while Rod Stewart's voice and the drum kit spill over from the front stage into the rear. The sax solo appears centered in the rear speakers, directly behind the listener's head, as does the keyboard intro to "This Old Heart of Mine." Interestingly, the drums move almost entirely to the rear for "Still Love You."
Editor’s Note: Atlantic Crossing was part of Quadio bundle #8, which also contains ZZ Top’s Tres Hombres, The Modern Jazz Quartet’s Blues On Bach, and Beaver & Krause’s All Good Men & Gandharva (the former never before released in quad!).
