The Plangent Process

Discussion in 'Audio Hardware' started by Stephen Murphy, Dec 8, 2014.

  1. Stephen Murphy

    Stephen Murphy Forum Resident Thread Starter

    Edmonton Alberta
    Since there are so many good mastering-minded minds tuned into this site, I thought there should be a thread about the Plangent Process since it is being so highly touted. Reading through some of the literature found here on their website they are saying "The result of this novel state of the art DSP is a stunning stability and transparency previously unheard from these classic sources - even surpassing the raw playback directly from the analog source." That is to say, their processed digital version sounds better than the original tape itself.

    My technical skills are limited, but as I understand the process their software locks onto the test tones on the tape. As the tones fluctuate, even minutely, their software determines what the tone "should have done" and processes the underlying musical information accordingly. This is definitely in the realm of heavy digital processing and quite far from the purist approach that Steve has described with regard to his work. Wondering what the minds here think about it.
    Kkfan and ruben lopez like this.
  2. Stephen Murphy

    Stephen Murphy Forum Resident Thread Starter

    Edmonton Alberta
    Just as a followup to my own post, Bob Ludwig talks about it when discussing his new Springsteen masterings:

    "The process allows the tape playback to sound closer to the output of the mixing console than ever before. It yields better separation, less distortion and a solidity to the sound that can be really remarkable." Recovering lost frequencies and digitally correcting wow and flutter and other timing issues, the Plangent Process reveals, as Ludwig puts it, "a sonic depth and clarity not heard since the original mix-down session." Neil Young and Grateful Dead are two artists that have already embraced Plangent for their reissues.

    The concept of digitally correcting wow/flutter and recovering lost frequencies by having software fill them in does not strike me as a good idea if good sound is the objective.
  3. IanL

    IanL Senior Member

    Oneonta, NY USA
    All I know is those Grateful Dead studio albums from HDTracks that used it are AWESOME.
  4. subframe

    subframe Forum Resident

    Bay Area
    Brilliant. I'd love to hear the results of this.
  5. allyn22

    allyn22 New Member

    Does anyone know if there is an currently updated list of albums, box sets (or whatever) that have been processed with the plangent process?

    I did buy the Bruce Springsteen box set and it does sound much better than the standard CDs I previously had of the same material.

    I'd really love to hear Boston, Kansas and Styx processed with Plangent.
    longdist01 and bleachershane like this.
  6. cdash99

    cdash99 Forum Resident

    The Grateful Dead live set 'Sunshine Daydream' sounds phenomenal.
    jonwoody, arcamsono, Freebird and 2 others like this.
  7. Stone Turntable

    Stone Turntable Dedicated Follower of Hi-Fi

    New Mexico USA
    It's amazing how many great-sounding things in audio don't seem like a good idea in the abstract.

    The grand kickoff IIRC for demonstrating what Plangent could do was the Grateful Dead Winterland 1973 box, which sounds absolutely brilliant. From the technical info:

    Notes on Mastering Winterland 1973: the Complete Recordings

    The two-track 1/4" tapes were originally recorded on a Nagra IV running at 7.5 inches per second by Bill "Kidd" Candelario as part of the normal tape documenting done in 1973. Kidd employed a mic split which permitted a different mix to tape than that to the PA system, with minimal processing allowing the clearest possible signal path to tape.

    We have attempted to preserve this excellent recording by using current technology to enhance its fidelity as never before.

    The first step in this process was to transfer the original analog master tapes to a digital format. This was done by using a Pacific Microsonics HDCD A/D converter at the highest possible digital resolution, 192KHz/24bit (for comparison, a standard CD is 44.1KHz/16bit).

    The resultant audio files were then sent via hard drive to Plangent Processes in Nantucket, MA. Plangent Processes utilizes a novel proprietary digital signal processing system called Clarity. The process analyzes the tape, searching for artifacts of the recording stream that happen to contain highly accurate timing information, which then reveal the mechanical imperfections of the original tape recorder's performance as it was making the initial master recording. To obtain this timing information, the original transfers to digital actually had to be done with the master tapes running at half speed, 3.75 inches per second.

    This information was then employed as a guide to gently but firmly correct the data of the digital transfer such that the sonic performance in terms of speed, pitch and tempo was indistinguishable from the board output. In this case the original 7.5 inches per second recordings contained significant amounts of wow and flutter, as would be routine even in the professional machine used to make these recordings. By undoing the wow and flutter we can now hear the performances in their original perfect pitch, and with steadiness of rhythm and overall clarity intact.​
    Last edited: Dec 22, 2014
  8. Jack Flannery

    Jack Flannery Forum Resident

    Houston, TX
    You state fact! Awesome, indeed.
  9. MrRom92

    MrRom92 Forum Supermodel

    Long Island, NY
    It's an interesting process, it locks onto the bias signal printed on the tape.

    The issue is that there are speed fluctuations both on recording and on playback.

    With the technology we have in 2014 I wonder if it would be possible to recreate this in the analog domain. Similar to how mastering-use tape decks have a preview head. The audio from the preview head can be analyzed in real time, with the data being used to minutely control the speed of the capstan motor.

    I don't think it would be impossible, I just think it it would cost far more to develop than anyone is interested in spending. I also think we're trying to put out a match with a firehose.

    15ips tape sounds fine without digital levels of accuracy. The best tape machines get pretty damn close anyway. There's no real issue to take care of here in most cases.
  10. jh901

    jh901 Forum Resident

    Aside from the Springsteen box, which physical discs have "plangent" mastering work?
  11. Daedalus

    Daedalus I haven't heard it all.....

    Another great plangent set is the Grateful Dead Cow Palace New Year-1976-77-"Spirit of 76". Just listening yesterday-really terrific sound.

  12. A lot of Grateful Dead discs. I have been listening to discs that used the Plangent Process for a couple of years now and I am very impressed. You can start with Sunshine Daydream.
  13. sacsongs

    sacsongs Forum Resident

    St. Louis , MO
    Curious what Steve's thoughts are on this equipment/process?
  14. Stephen Murphy

    Stephen Murphy Forum Resident Thread Starter

    Edmonton Alberta
    Saw an interesting post in a Grateful Dead thread that mentions the Plangent Process :

    I saw a presentation by the Plangent guys a few years back, and they explained the technology and then played examples of "with" and "without" using it. The examples included Billy Joel, and some others, but the most striking were Simon and Garfunkle tracks. Apparently they transferred the Simon and Garfunkle tracks from several of the album masters using the technology, but when they were played and compared by unnamed record executives, those persons felt like the non-Plangent versions sounded "more like when we were listening to them in the 60's". When we heard the differences in the examples played, they were not subtle, and the Plangent versions were truly much much better, light-years better.

    Looking beyond the author's obvious enthusiasm for the process, what he is saying is that CBS tried some tests with it, and didn't like what they heard. He uses the term "unnamed record executives", but it could have been Roy Hallee that gave it the thumbs down, who knows? As it turns out, the S&G titles have been recently released in hires using more traditional methods and they sound very good according to the people here. Anyway, interesting that the "Plangent" sound isn't a slam dunk for everyone who hears it.
    Kkfan likes this.
  15. Stone Turntable

    Stone Turntable Dedicated Follower of Hi-Fi

    New Mexico USA
    Since we're extrapolating and reading between the lines, what this anecdote seems to be saying is that there are trade offs involved between choosing to stay in the analog realm (we all know that AAA vinyl can sound amazingly great, for example) versus using Plangent's technology to improve analog-derived sound in the digital realm. I've been assuming that Plangent is an incredible tool for restoring and upgrading live recordings produced with less than studio-quality gear, whereas master tapes recorded with world-class studio tape recorders don't have the limitations and flaws that Plangent fixes to the same degree, so you might lose more by going digital than by staying with pure stellar analog.
  16. Stephen Murphy

    Stephen Murphy Forum Resident Thread Starter

    Edmonton Alberta
    I think you make a good point about the live recording aspect for another reason as well. The "tape limitations" are only one layer deep in a live recording, assuming is was done without a lot of overdubs. In a studio recording, there are many tracks recorded at different times. Maybe even on different machines. It wouldn't make much sense then, to take one track of that, say a piano, and try to stabilize it to a test tone. You may be doing greater harm to the other tracks that were recorded separately and don't share the piano track's variations in speed/pitch.
  17. jamiehowarth

    jamiehowarth Forum Resident

    Sorry about the wall of text but the context is important. I was there also.
    Absolutely not Roy Halee (check the spelling), and whoever told this anecdote was indeed very enthusiastic, as was everyone in the room except the exec, who preferred the lo-fi version that "sounds like the 60s" for sentimental association to a large degree, in a very quick listening session arranged in Mark Wilder's room on a day that unfortunately Mark was out sick (typical of our luck in those days of 2006).
    The others present clearly vocal were of the belief that the versions were indeed light-years better, and were squirming with discomfort when the session was later attended by one of the Legacy guys who obviously had a much different approach to the philosophy of remastering than they did. The chief-engineer of Sony (the late Dave Smith) was particularly upset. One example of the difference between the reality of what the process does and what "sounds like the 60s"… one of the clear advantages of the technique …. is a rock solid imaging rendition, since the high-frequency swimming is removed (that's not azimuth it's pitch shift) and in the latest version developed for the Springsteen releases the azimuth is also stabilized.
    One of the samples played was from a George Massenburg mix that George had heard and approved himself, which I guess is analogous to having Hallee hear the S&G which parenthetically by the way were far from masters ---more like Dash3 dubs and they sounded poor and probably should have been rejected by us as examples.

    The Earth Wind and Fire tape (a 30IPS copy made to comp together the Greatest Hits package) showed clearly the precision with which George sets up his panning, and the 8 positions he sets out with tone to flank center. In the original these positions were indeterminate, and in the Plangent version they were precise and solid - 1/4 L R 1/2 L R --- I can just picture GML all over it. The exec preferred the version that swam. We then played a Stax Volt LCR hard switch-panned mix and he asked where was the stuff in between the speakers. That's when the guys started to get really restless rather than contradict the boss. There was nothing between the speakers, because - well, there was nothing between the speakers. "But I like the stuff between the speakers". Fine, but that's not the tape.
    A very sweet and gentle man from accounting was brought in who was asked which was more "musical, more like the truthful version"... apparently this guy was the savant who had really good ears with no agenda … he preferred the Plangent version. It was disheartening.

    I was later told of a recovered dub from Eddie Simon's closet of a dub of Parsley, Sage that was made at the same time in 1975ish as the worn out dub they were using for CD release, the master having apparently been "worn through" (which we have techniques for as well)… IOW the newly discovered dub was brand-new old stock made by the same dub engineer on the same day. Same handwriting. The individual sharing this information contends that when a blind test was performed of the three versions now available the worn dub won the "test" because its dullness best matched the recollection of how the record sounded "in the 60s". So what actually won was the guy's recollection of the spectral content in his head, not what was actually recorded by Halee, for whom by the way I assisted, and I know what his stuff sounds like having actually been in the room with it. So while it's fair for speculation to exist why the 2005 team at Sony was of mixed opinion, it wasn't Roy and I have to knock that down.

    Now let me defend the guy - who's extremely good at what he does and conscientious - while I disagree with his appraisal I know where he's coming from and have to respect it - I'm the same way…
    I'm working on a 60s remaster where the famed engineer/producer mixed on seriously duller speakers than a contemporary system, hyped for vinyl and AM radio and I've lined up to the tones and it's bright as hell, way brighter than I remember. So maybe I should disregard the tones and go with my belief in "what it sounded like in the 60s"?
    That won't fly. But it needs EQ. And I want to match as best as possible what he heard.
    So knowing what he mixed on (604s, which are easy to cross-EQ around) I've asked the esteemed engineer of the era to tell me what he had at home. I'll go on Ebay and buy them and listen to the flat to the tones version on that system and taper the EQ of the today release with that in mind and then and only then will I be confident that the remastering is honest to the intent of the original. I understand the scrupulousness. I'm the same way. I remember how this record sounded on a V15 and a Dyna amp and a pair of AR4xs ---that's what it should timbrally sound like. But if the distortion and scrape flutter and false (perhaps romantic but wrong) imaging haziness is cleared that's what it sounded like to the producer of the original record as he mixed it, before a generation of tape effed it up.
    By the philosophical logic of the above the Parsley record is invalid if played on an ATR102, let alone Plangent. Nobody wants to take the philosophical abstraction that far, do they?

    Mark Wilder and Vic Anesini are advocates, and Vic was there that day and he preferred the Plangent versions as well. I just think the philosophical beliefs of this one particular producer over-rode everything else, and I'm still hoping that guy will do a clear fair test with the 2015 version of the system and settle this. I'm totally confident he'll like it, largely because I know very very well and understand the guy's aesthetic integrity. If we were indeed diminishing the veracity of the material that would be heinous and I'd pull the product. But the EQ curve is what he wants to nail down --- that's where the nostalgia should start and end. The material was distorted by the machine, and we're convinced that the distortion is not part of the aesthetic intent of a guy like Halee--- if he packed the tape with level to get it to de-ess that's still there. But if the piano is wavering and the harmonics are hash and masked, and if the imaging is indeterminate because of edge riffle (which the process fixes) or speed instability messing with the spatial perception- well that's all good.

    Ludwig was similarly skeptical for years, rejected it out-right in concept. Not having heard much of it other than second hand. He was totally and completely won over on the Springsteen package, and while having no financial interest whatsoever he did a total vocal 180 on it.

    We offer to Steve, or any other skeptic, a gratis test at our expense on any material they choose.

    As for filling in the blanks in an analog recording being a bad idea --- that's simply not what happens. The original digitization (which today with Mytek and a few other converters sounds like the tape in an A/B at 96/24) contains what it contains, and the warp algorithm maintains the phase relationships perfectly - it simply moves the time base to exactly where it originally was at the tape machine input. It removes only the jitter and the IM -in a null test with the original digitization it nulls to 24bits (-140db).

    We've worked extremely hard for over 10 years, and the intrinsic prejudice against digital and against DSP has been much harder to address than the technical issues. I love the comment that things sound good even though they might be different in the abstract - in our case different from what has become some of the folk wisdom surrounding audio…
    If the algorithm had serious deleterious artifacts that it could introduce it would have been caught by now. One thing we have changed since this audition has been to remove a zero DC-basing of the audio that was a goof by a designer who thought it a good idea, Bruce Madducks caught that, and we're grateful. We are constantly improving… But I don't think that's not what "CBS" heard, but rather an honest philosophical approach that would pre-suppose that the improvements were suspect… and that clouded that early Sony test.
    We're confident that we are doing no harm, but that a sentimental nostalgic approach is not what's on the tape, not what was in the control room, not what came off the console.

    The reviews on the Springsteen are out 2 months now, and not a single review has been unfavorable.
    Last edited: Jan 6, 2015
  18. Billy Infinity

    Billy Infinity Forum Resident

    The Springsteen CD box sounds breathtaking. All seven albums. Kudos to Jamie, Bob Ludwig, Toby Scott, the Boss, and everyone else involved.
  19. MrRom92

    MrRom92 Forum Supermodel

    Long Island, NY
    Thanks for the super in-depth post. I love the technical details like that, that's what a lot of us come here for. The process sounds interesting and I think I will have to seek out a plangent version of a recording I'm familiar with to truly hear the difference for myself.
  20. jamiehowarth

    jamiehowarth Forum Resident

    The claim is that the improvement of the removal of the generation loss at the analog tape level is more beneficial than one A/D D/A step and that's more a religious argument at this point, but Chris Bellman mastered from the digitals. Doug Sax did a great demo at AES where he played a commercial CD done by another mastering engineer and then the LP he cut --- it sounded phenomenal - and then he revealed he'd blindsided the room - it was from a 192/24 digital.

    We actually did the restoration of The Promise cut from the multitrack and not only fixed the piano, but went track by track, and matched the timing of the Total Recall of the original SSL mix -- the technique would not work if it couldn't maintain sync. In fact a Queen concert DVD where they were stuck with the VTR audio because there was no time code on the 30IPS 1/2" mixes used for a CD release of the same show years earlier were a piece of cake. We tracked the bias on the 2tracks and they were easy to post-sync against picture without SMPTE. So isolating out one piano track and laying it back into the 2 track mix would be nuts. But laboriously processing a non-live 24 track has been done and the results are excellent.
    Last edited: Jan 6, 2015
  21. Stone Turntable

    Stone Turntable Dedicated Follower of Hi-Fi

    New Mexico USA
    It's kind of a thrill to have amateur hour (me posting my pure guesswork thoughts) answered and corrected with your insightful, detailed, professional information — straight from the horse's mouth, so to speak. Many thanks!
  22. jamiehowarth

    jamiehowarth Forum Resident

    So are we, no reply. Hope to speak when it's right.

    We see this time and again. Everybody is rightly proud of their workflow, often based on ancient gear, and we're all new, and rad and therefore controversial.
    There's also a generalized bias against new in the pro audio business. It's as if the last legitimate piece of gear was made in 1975. And the only popular bankable item is a convolution filter emulation of 1965.
  23. MrRom92

    MrRom92 Forum Supermodel

    Long Island, NY

    Weren't the studer a820's being produced as late as '93? Those are certainly suitable and in use would probably compliment the plangent process quite well :p
    Shak Cohen likes this.
  24. Vidiot

    Vidiot Now in 4K HDR!

    Hollywood, USA
    It's still early in the year, but this is the best damned post I've read on the SH Forum in some time. Brilliant info, Jamie, and thanks for sharing your experiences here. :righton:
  25. jamiehowarth

    jamiehowarth Forum Resident

    Digital noise is a pain in the neck --- probably the best machine for Plangent is a 440 or a non-digital very early A80. The ATR makes digital noises that get in our way, so do the 800 - 810 - 820 Studer.
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