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.

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

As one might expect for a classic rock album of its stature, Machine Head has been reissued countless times in the five decades since its original release. One could be forgiven for thinking there’s little more material from these sessions left in the vaults to mine, but the 50th anniversary box set does actually contain quite a bit of previously-unissued content. 

For immersive music fans, the most interesting component of the set would certainly be the audio-only Blu-Ray disc containing brand-new Dolby Atmos mixes of the original seven album tracks and B-side “When A Blind Man Cries” from Dweezil Zappa (son of Frank, who's famously name-checked in "Smoke On The Water"). The Blu-Ray also contains a digital transfer of the rare 1974 US quadraphonic mix, as well as three bonus tracks in 5.1 surround sound.

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

Zappa’s 50th anniversary Dolby Atmos mix unbelievably marks the fourth(!) occasion that Machine Head has been remixed in a multichannel format. Two different quadraphonic mixes of the album were released during the 1970s, as well as a 5.1 surround mix in the early-2000s.

There is a relatively short list of albums that have been remixed in surround sound twice (key examples include Aerosmith’s Toys In The Attic and Chicago’s self-titled second album)–and an even more select few that have garnered three surround mixes (such as Mike Oldfield’s Tubular Bells and Carly Simon’s No Secrets)–but I can’t think of another title with four unique multichannel iterations.

Though the new 50th anniversary Blu-Ray disc does not contain all four multichannel mixes, I felt this article represented a good opportunity to briefly analyze and break down the availability of each version.


In addition to the standard 1972 stereo LP release (TPSA 7504), EMI/Purple Records also issued a quadraphonic edition of the album on LP (Q4TPSA 7504) and 8-track cartridge (Q8TPSA 7504) in the UK, Europe, and Australia.

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

During the early ‘70s, EMI commissioned four-channel remixes of several notable albums in their catalog–including Pink Floyd’s The Dark Side Of The Moon and Atom Heart Mother. Their quadraphonic LP’s used the CBS “SQ” matrix encoding process, meaning that one would need to purchase an external decoding device to extract the rear-panned information upon playback. Unfortunately this recovery process was imperfect, often severely reducing the separation between the front and rear channels.

The best way to experience this quadraphonic mix is undoubtedly via the 2003 EMI UK SACD, which contains a digital transfer from the ½-inch four-channel master. The 2012 40th anniversary box set also contains the UK quad mix, albeit in lossy DTS audio on a standard DVD.

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

The layout of this immersive mix is simple, but effective. It sounds like you’re standing in the rehearsal space surrounded by the band, with the drums, bass, and lead vocal arrayed across the front channels, while Ritchie Blackmore’s rhythm guitar and Jon Lord’s organ are isolated in the back corners.

Blackmore's solo in "Highway Star" takes the phantom center, whereas his lead in "Smoke On The Water" pops up directly behind your head to great effect. Gillian's harmonica in "Lazy" also appears from the rear, as does Paice's short drum interlude before the last chorus in "Space Truckin'."


By 1974, Warner Brothers (who distributed Purple Records in North America) had introduced their own line of quadraphonic products. Their four-channel LPs–commonly referred to as “Quadradiscs”–used the “CD-4” system, an entirely different technology developed by JVC in Japan that kept the four discrete signals on the LP completely separate (unlike the SQ matrix encode/decode process, which blended the signals together and then imperfectly pulled them apart again upon playback). 

Though CD-4 was capable of performance rivaling any of the matrix systems, the format was plagued by a multitude of issues including an arduous user calibration process, temperamental bouts of distortion, and high frequency roll-off.

For reasons unknown, a completely different quadraphonic mix of Machine Head was prepared specifically for the Warner quad LP (BS4 2607), 8-track cartridge (L9B 2607), and reel-to-reel tape (WSTQ 2607 QF) editions in the United States. 

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

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.

Whereas Gillian's screams during the intro to "Highway Star" each fade in from a different corner in the UK quad mix, here they're all centered in the back speakers. Additionally, the higher-register harmony vocals during the chorus to "Smoke On The Water" are now isolated in the rears. Perhaps most fascinating of all, the lead vocals in "Space Truckin'" appear entirely from behind as well.


Nearly three decades after the failure of quad, WB/Rhino embraced 5.1 surround sound music with the DVD-Audio format. Machine Head was of course chosen as one of the first titles, and the mixing team of John Kellogg & Paul Klingberg was tasked with remixing the album in 5.1 from the original multitrack tapes. The 5.1 mix was issued again in 2011, this time on SACD solely for the Japanese market.

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

There have been a number of surround sound editions of Deep Purple’s Machine Head, but only the 2003 EMI SACD and 2012 40th anniversary box set contain the 1972 UK quadraphonic mix. The 2001 DVD-Audio and 2011 WB Japan SACD instead use a modern 5.1 surround remix created by John Kellogg & Paul Klingberg. The 1974 US quadraphonic mix is exclusive to the 2024 50th anniversary box set.

Back in 2021, I had the chance to ask Kellogg about his experience working on the album:

While working on Deep Purple’s Machine Head, Paul [Klingberg] and I got to mix “Smoke on the Water” which was an iconic classic rock anthem of our high school days. I used to watch buddies burning rubber, smoking their tires doing neutral drops in the high school parking lot while blasting “Smoke on the Water” on an 8-track in their cars. Decades later, Paul and I were working on it one evening and we just had this moment where we looked at each other and shouted, “Do you realize what we’re doing? We’re mixing freakin’ “Smoke on the Water”! How awesome is that?”

On Deep Purple’s Machine Head, we found entire drum breaks that were recorded on separate tracks then mixed and spliced into the 2-track master reel. It was fascinating and a little mind-bending at times to make it work in 5.1. We also found an entire song, “When A Blind Man Cries,” that had never been mixed or released. So we mixed it, and it was included on the DVD-Audio release.

John Kellogg, August 2021

The Klingberg/Kellogg 5.1 mix offers more of an "expanded stereo" presentation to my ears, with elements such as the rhythm guitar and keyboard positioned between the front and back soundstages. The rear channels are used more to create a sense of depth, rather than supply completely-isolated instrumentation. Gillian's vocals are mostly confined to the fronts, while the center channel is utilized primarily for Roger Glover's bass guitar.


Specifically for the 2024 50th anniversary release, Dweezil Zappa was tasked with remixing the album in stereo and Dolby Atmos. To my knowledge, this marks the first occasion that he's been involved in a remix project of this nature. The Atmos mix is also available to stream on Apple Music, Tidal, and Amazon Music.

In a short video interview with radio host Matt Pinfield, Zappa elaborated a bit on his approach to reimagining the record for the 50th anniversary release:

There's so much about this classic record to love. But now with another version in this box set, you have a chance to hear some things maybe you didn't know existed, and that was the whole goal. 

[In “Smoke On The Water,”] I wanted to make the drums as big as possible. I want to hear every single tom fill and I want to hear more things happening from the keyboards. So I would take those parts and I would make those much louder. Especially in Atmos I would actually start moving them, so that they would sweep into the new section and give you a bigger impact on the choruses. 

Dweezil Zappa, March 2024

For better or for worse, the 2024 remix certainly offers a unique spin on this legendary material. Elements that were left relatively dry in previous mixes, such as the keyboard solo in "Maybe I'm A Leo" and vocal chorus to "Space Truckin'," have now been treated with copious amounts of reverb and delay. In some passages this works well, but more often than not I found it distracting.

I was curious to see how the height speakers would be engaged throughout the Atmos mix, but oddly enough they're used primarily to elevate Ian Paice's drum kit. Blackmore's rhythm guitar tends to stay mostly in the front left channel, while Lord's organ extends out towards side right. There are even some fun around-the-room swirling pans, like with Glover's bass solo in "Pictures Of Home" and percussion during the breakdown in "Space Truckin'."

Deep Purple Machine Head Atmos 5.1 50th 2024 Quadraphonic

Though my ideal Machine Head Super Deluxe Edition would have gathered all four multichannel mixes on one disc, as well as Roger Glover’s 1997 stereo remix, it’s still a fairly-comprehensive package for collectors and immersive music fans. The rare 1974 US quadraphonic mix is arguably the most interesting new inclusion on the set (perhaps this will later be issued again as part of Rhino's ongoing "Quadio" line?), but the new Dweezil Zappa Atmos mix isn't without its moments either.

I feel it's also important to remember that the Atmos mix could just as easily have been kept exclusive to the streaming services, as so often happens with new immersive renditions of classic albums. If anything, the availability of so many different versions of Machine Head in both stereo and multichannel format is a testament to the rich legacy of this amazing music.

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About the Author
Jonathan is an audio engineering enthusiast from New York with a passion for immersive audio, having amassed a formidable collection of multichannel optical discs and quadraphonic vinyl. He earned his undergraduate degree in Television-Radio from Ithaca College and Master's degree in Audio Technology from American University.