Among the most celebrated reissue campaigns of the past several years is the Joni Mitchell archives, an ongoing effort from Warner/Rhino centered around uncovering previously unreleased recorded material from singer-songwriter's vast back catalog.

Each reissue so far has covered a specific era in Mitchell's career, such as the late 60s period in which she was signed to the Reprise label, containing a plethora of studio and live material in box set form.

Much to the chagrin of some audiophiles, perhaps the only key aspect missing from these otherwise comprehensive releases is immersive audio - specifically, a Blu-Ray disc with 5.1 surround sound or Dolby Atmos remixes.

The latest reissue in the series, The Asylum Albums (1972-1975), covers four of the most popular albums in the Joni Mitchell canon: 1972's For The Roses, 1974's Court and Spark (along with its accompanying live release Miles of Aisles from that same year), and finally 1975's The Hissing of Summer Lawns.

As many longtime immersive music fans may recall, the Court and Hissing albums were remixed in the quadraphonic format and released on specialized four channel vinyl & tape editions by Asylum records in the mid 70s. Seeing as the quadraphonic versions have become quite desirable in collectors' circles for years now, they are a notable omission from the set.

Though the box set once again disappointingly forgoes any immersive audio content on disc, brand new Dolby Atmos remixes of all four albums quietly became available on the streaming services soon after its release. Mixed by Ken Caillat (perhaps best known for his engineering & production credits on Fleetwood Mac's Rumours) and Claus Trelby at Marshmellow Skies studio in Westlake Village, CA - with oversight from Joni Mitchell herself - these new Atmos versions sound absolutely phenomenal.

1972's For The Roses is a relatively sparse production not necessarily suited to surround sound, as most songs consist of just piano or acoustic guitar accompaniment to Mitchell's voice, yet the Atmos mix manages to retain and even enhance the haunting intimacy of the original recording.

"Cold Blue Steel and Sweet Fire" is definitely a highlight, kicking off with the twin acoustic guitars panned hard left and right - just as in the original stereo mix - but hovering somewhere between ear level and the heights. James Burton's electric guitar appears primarily in the left side surround speaker, while the end sax solo flares off mostly in the rear right height speaker.

Rather than residing solely in the center speaker, Mitchell's vocals fill the entire front soundstage and often extend out a bit farther into the room for a more cohesive feel. The sound quality is excellent, with plenty of 'punch' to the low end and a crispness to the acoustic instruments that never comes off as harsh. If I have one (minor) critique of the Atmos mixes throughout the set, it's that the lead vocals seem ever-so-slightly too prominent at times - particularly on the sparser songs like "Same Situation" or "The Boho Dance."

Court and Spark (1974) is much more elaborately produced, featuring various layers of percussion, horns, and vocals suitable for a wider spread around the room in the Atmos format. "Help Me" features the backing vocals in the side and rear surround channels, while the horns extend upward into the height speakers. Just as I'd hoped, the multi-tracked vocal chorus at the end of "People's Parties" makes great use of the extra space as well.

The iconic whistle-like sound that kicks off "Free Man In Paris" appears primarily in the rear height speakers, with the drums and bass spread across the front channels while the electric guitars, backing vocals, and other ancillary instruments appear partially or entirely from behind the sweet spot. This stands in stark contrast to the quadraphonic version, in which the drum kit is mixed entirely to the rear speakers for an "inside-the-band-on-stage" kind of effect.

Though it's a live recording, Miles of Aisles' Atmos mix actually makes fairly extensive use of the additional speakers to put the listener in the middle of the L.A. Express. It's a bit more conservative than the studio albums, but there's definitely more going on back there than just venue ambience and applause. "You Turn Me On, I'm A Radio" places Larry's Nash's piano mostly in the side right speaker and Robben Ford's electric guitar in the side left, with the rhythm section and Mitchell's vocals spread across the fronts. Amazingly, the sonics are nearly as good as the studio recordings to my ears.

Tom Scott's sax in "Big Yellow Taxi" fires from the front right channel up into the heights, while keyboards percolate from behind and electric guitar highlights appear suspended between the front left and side left speakers. Miles of Aisles also features a number of selections from Clouds (1969), Ladies Of The Canyon (1970), and Blue (1971). I'm hopeful that Dolby Atmos remixes of those remaining studio albums from the late 60s and 70s will appear in the near future.

1975's jazz-tinged The Hissing of Summer Lawns, my personal favorite of the four albums, is arguably the most impressive in Atmos. The new immersive mix really peels back all the layers: throughout "In France They Kiss On Main Street," you can hear backing vocals from James Taylor, Graham Nash, and David Crosby in the rear speakers and Skunk Baxter's guitar licks primarily in the front height channels.

Brass highlights often appear in the back corners, mixed partially to the heights for a more enveloping sound. There are even some fun passages with movement in the surround field, such as when Joni's voice hops channels midway through "Harry's House/Centerpiece" or shifts to the height speakers for a key moment in the title track. The closing track, "Shadows and Light," is an immersive tour de force with the layered a capella vocals spread all around and above the listening space. 

Overall, these are among the finest Atmos mixes I've heard to date. It's a shame that they're being kept exclusive to the streaming services, but perhaps that will change in the future. I know I'd certainly invest in a series of Blu-Ray discs containing these mixes as well as the 70s quadraphonic versions.