A Trialogue on Historical Recording Restoration by AM, JEB, & BO

      Date posted: January 10, 2012

Editorial - A brief history of XR remastering, by Andrew Rose, Pristine Classical Recordings

Five years since the first breakthrough

It’s hard to believe it - for me at least - but five years has passed since I first stumbled accidentally over the basic procedure which was to become the crucial underpinning concept behind XR remastering. Since then I’ve used the method on many hundreds of hours of music, and seen it adopted by other remastering engineers working in the same field. I’ve been able to refine it, adapt it, and take advantage of new technologies and computing power, which continues to improve the results it achieves.

It all began over the Christmas and New Year period of 2006-7. I was working on Toscanini’s classic 1936 New York Philharmonic recording of Beethoven’s Seventh Symphony (PASC068) and it wasn’t going well.

In theory everything should have been fine. I had a set of near-mint HMV pressings, and, having figured out a couple of years previously how best to cope with their ubiquitous “bacon frying” crackly surfaces, this should have been a pretty routine task. At the time I had a reasonably fixed method of working to deal with everything a decent-quality 78rpm disc could throw at me, and this was working as expected. The trouble was, the results sounded truly awful, if not actually painful!

(Over the years a number of recordings I’ve worked on have given me headaches, though less so more recently - but this week, and for the first time ever, I worked on a recording during which I became so emotional and choked up by the power of music and performance I had to stop, walk away, dry my eyes and pull myself together before I could continue. More of that anon…)

Anyway, back to the Toscanini. I spent days on that recording. There was a terrible harshness to it that I quickly realised had nothing to do with my pressing, the disc surface, or indeed anything a remastering engineer would normally tackle. The major flaws that were hurting my ears were literally “hard-wired” into the recording. Something must have gone badly wrong with the microphones, or the mixing equipment, or the disc cutting amplifiers - but what?

It seemed to me that no amount of equalising, boosting or cutting of frequencies I could manage was working - I simply couldn’t work out how to attack it. This, for me, was unusual; I’d spent more than a decade mixing live
radio at the BBC, something that hones an almost instinctive ability to nail a problem frequency and cure it, fast, on air, so as not to annoy several millions of listeners. Yet now I had to admit it: the Toscanini had me beaten.

I did though have one tool which offered assistance in a way unavailable to me when mixing live radio - in many ways similar to something I’d first seen a colleague using at the BBC’s Maida Vale studios to engineer a David Bowie session back in the early 1990s: FFT spectral analysis. Back in the 90s it was a very difficult thing technically to do live, but the very top-end mixing desks of the day allowed the sound engineer to switch the channel meters (LED bar meters) into a mode which gave an accurate spectral analysis which gradually averaged out as a track played. It’s the kind of thing which, in a much simplified version, started to show up as colourful bar graphs on cheap hi-fi products in the 90s, giving an idea about the amount of volume at a given range of frequencies.

My colleague, who had been producing rock sessions at extreme volumes for many years (he was also responsible for the sound at massive concert broadcasts, such as 1985’s Wembley Live Aid event), and was notoriously hard of hearing as a result. He was also one of the very best in the business, and one of his secrets was the use of this spectrum graphing method to visually check and correct for any tonal deficiencies in his own hearing. If there were any unusual “holes” in the bar graph he could boost those frequencies, and he’d learned to know what kind of overall mix of bass, midrange and treble to look for on the 48 parallel LED meters. At the end of a long day’s recording, when one’s top end response was severely compromised by the brain shutting down its ears to protect them, my colleague was still able to produce results which sounded great - yet where any other engineer would probably have boosted the treble to a ridiculous amount simply to be able to hear it.

Fifteen years later and a piece of software called Har-Bal did a similar thing on a PC - expect in this case instead of gradually averaging out as a multitrack tape was played through it, it took a digital music file, analysed it, then showed you the results in a continuous on-screen line graph. It also allowed you to load up a second music file, normally a reference file of something you felt was a good recording, as a visual guide to anything that might be wrong with your original, possibly for the kind of reason outlined above. (As with most music software it sells best to those working in the rock music industry.)

I’d downloaded a good reference file for my Beethoven 7 from eMusic - the London Symphony Orchestra doing the same work under Haitink - and I was playing around adjusting various frequencies on the Toscanini and getting nowhere in particular. Finally, in a fit of frustration, I did the one thing which every manual and guide says you must never do: I lined up the two graphs perfectly with each other (or at least, as perfectly as was possible given the somewhat limited resolution of that early version of Har-Bal at the time). It was a kind of “sod it, what the hell?” type approach - after all it could hardly sound any worse.

Using my mouse, I pushed and pulled at the line depicting the frequency response of the Toscanini until it lay directly “on top of” the Haitink, the effect of which is to create an equalisation curve to match the average volume levels at all analysed frequencies of the former former to those of the latter.

Then I pressed play.

What I heard was to change my world! Once I’d picked my jaw up off the floor, it set into a grin which stayed with me for the rest of the day, if not the week. I’d accidentally stumbled across something I think nobody had ever heard happen before - though it took me a long while to get fully to the bottom of it.

It was pure luck - or was it intuition? - that I’d chosen to match Toscanini’s Beethoven 7 to a modern Beethoven 7, rather than any other work plucked at random using similar musical forces. It turned out that this matching of works was the key to this success, and probably therefore also the reason nobody had figured this out before. Because the works, and thus the orchestral forces producing their sound, were essentially the same, the normal rules governing this kind of equalisation didn’t apply. Quite the opposite, it turned out.

What the matching up had done was to create an equalisation curve so complex it would be beyond even the most experienced, golden-eared sound engineer to re-fashion by listening and hand-adjusting alone. It unmapped the complex interrelations between the 1936 recording equipment which had conspired to produce such poor sound quality - or if you prefer, it had reverse- engineered out many of those faults inherent in the original recording.

It would be nice to think this is all we need to do: feed the music in one end, add a reference, mix well and serve. Alas this isn’t the case. It turns out that many of those vintage recordings need to be hauled about quite severely. Instead of a bit more treble here, or a boost in the bass there, the complex equalisation that gets applied looks, when viewed as a graph, less like a series of smooth curves and more like a particularly vicious Alpine mountain range. It’s up and down at steep angles and reaches some extreme peaks and troughs, in a seemingly random fashion. It’s this wild sonic havoc which helps create that distinctively “vintage” sound in older recordings, more so than the hiss, crackle and limited upper frequencies that characterise those badly faked “old recordings” in the movies that never sound quite right to those of us who know!

Now whilst this re-equalisation makes the music sound great, it does the opposite with all the background noise inherent in any analogue recording, whether its disc surface noise or tape hiss, as this too is being hauled all over the same acoustic terrain. What was previous a nice, evenly-balanced background noise suddenly has major and very nasty zones of harsh hiss and noise. It’s difficult to listen to, and needs tackling. The ear likes (or tolerates) a nice even random white-noise-style hiss, but not one where noise frequencies are boosted to the extent of leaving what sounds like odd whistles, even if the music at those same whistling frequencies now sounds fine. Bring on the digital noise reduction - but applied in varying degrees across the frequency range to try and even this all out.

Put very simply, this is what I’ve been doing ever since: equalise an older recording to a modern equivalent, then filter out the excess noise this produces to try and create a quiet, but crucially a sonically even, white noise background. (It’s actually quite a bit more complicated than that but this describes the nub of it well.)

I’ve learned a lot since 2007. The tools at my disposal have progressed from being blunt instruments to something far more surgical. New ones have appeared which have transformed some of the most difficult aspects of the various procedures. I’ve realised just how important very precisely matched tuning is between source and reference. I’ve discovered the “hidden frequencies” in older recordings which inspired the label “XR” (it originally stood for extended response), and how to help make them properly audible again.

Meanwhile computing power has increased massively, to the extent that highly complex digital noise reduction techniques (for example) that were simply too slow to be practical are now everyday tools. No doubt this will continue - for the first time this week, for example, I’ve managed to preview my most extremely processor-intensive noise reduction routine on stereo material for the very first time. This involves taking one of the fastest and most expensive 6-core Intel i7 processors on the market and persuading it to run considerably faster than its makers intended (a process known as over- clocking), without overheating and literally burning it out, in order to squeeze more performance out of it. I imagine this result will shortly be a routine achievement, by which time the software’s authors will no doubt have cooked up an even more processor-intensive but sonically-superior method.

In the middle of last year we became the first to release recordings which had been pitch-stabilised using Celemony’s Capstan software. This is another major processor-hog. I was told to expect the initial analysis period for any recording fed into the system to take about as long as the recording’s real time duration - ask it to untangle an hour of music and you might as well do something else for an hour, while it runs your chips flat out at 100% and you hope they don’t start glowing. This same operation now takes me about 25 per cent of the original time thanks to that PC speed boost - meanwhile Celemony have won a thoroughly-deserved technical achievement Grammy for Capstan, to be presented in a few weeks’ time.

I don’t recall precisely when Ambient Stereo appeared on the scene, but like Capstan it was one of those things which, once heard, I knew I couldn’t do without, and it got added to the “XR” toolkit. I remember my nerves at issuing Ambient Stereo recordings, given the reputation of “fake stereo” processes for creating appalling recordings in the past. Yet this was different, and now the vast majority of our customers not only agree, but choose Ambient Stereo wherever possible.

Naturally there are other technical fixes which can be brought into play as and when required, and it seems that every time I think my PC is powerful enough to speed up my work rate a new must-have turns up which I can’t live without, but which slows the whole remastering process back down again and has me craving ever more computing power.

I still can’t always predict what results any individual recording will produce in advance of XR remastering, though I do have a much better idea now than I did five years ago. And like a drug addict, whilst I still crave that high I got the first time I heard it, I still get a real kick out of what I do hear, and remain permanently itching for my next sonic “hit”…

Andrew Rose 6 January 2012

Above Editorial Sent To AM & BO Without (And Seeking) Comment, by JEB

Reply From AM
Hi Guys,

I think what this guy is spouting is largely self-serving technobabble bullshit! Al the electronic frequency EQ in the known Universe will not compensate for poor phase accuracy and even poorer transient response in recording horns and ancient microphones. Talk about dealing with a literal “sow’s ear”! And you can’t turn that crappy old vibrating membrane, whatever it was, into an angel’s ear a century later no matter what you do.

Even the process of removing recording noise that often obscures the first and second overtones ensures that they cannot be synthesized out of thin air again, literally. In a mono recording all the noise and distortion are part and parcel of the production, and cannot be removed except at a cost.

And I’ve heard all the nonsense about somehow re-creating a stereo presence, which could only be possible by some sort of phase manipulation, which is by definition the addition of distortion to the original musical performance.

And that’s the truth! And I know it from long experience. When Mr. Rose may have been listening to Led Zeppelin in his basement, I was sitting in the restoration room at Abbey Road interviewing their best expert in saving historical recordings. Magical methods of  rescuing recordings have not been re-invented since then, 1975, though digital technology has helped somewhat.

cheers, Andrew

From JEB
Agreed! The Technological Imperative, alive and well.

Just thought this would be interesting in light of the latest Zenph (Sp?). I heard the Zuill Bailey/Manuel de Falla on Lisa Flynn’s New Releases on WFMT yesterday. and Colette wonders at “Izzy and The Ghost”.
I’ve been quite pleased by Marc Obert-Thorne’s and Wade Marsden’s work, generally as non-interventionist as possible, on Naxos Historical (which is not distributed in North America ) but readily available from MDT or Presto in England).
From BO
I finished reading the Pristine newsletter feeling very uneasy. Toscanini would be turning over in his grave???  Mr. Rose says his methods were successful until he met the T. recording. I wonder why he just couldn’t have left that one alone.  Now, he measures all  the old material against a modern recording. That surely corrupts the original material.  I am not being rhetorical when I ask, does this not change the original conception of the conductor and performers?  Karajan used to huddle with his producer after recording sessions to adjust balances and many of his later recordings are viewed as being under that cloud.  Now, heaven knows, I am willingly in the dark over most of the tricks performed in the recording studio today, but, what is done now is no excuse to mutilate what has been done in the past. The sound of old recordings is part of their heritage.  Andrew even contests the claims Rose is making for better sound.
I guess it comes down to hearing some of the Pristine catalogue. For myself, I have no problem with MONO, there is no doubt the hamfisted attempts at pseudo stereo that were tried early on were a disaster, but mono can be just fine and, in some cases, much better than some of the hard left-right early stereo.
When it comes down to it, I guess I would rather that Toscanini, not Rose, have the last word.OK, John, I think you have heard Pristine releases,  it’s over to you…..
From JEB
Gentlemen:I have confirmed, and am listening to the Toscanini Beethoven Seventh— it is in fact the New York Philharmonic recording. I am using the Bowers & Wilkins speakers and find that the sound although fierce, as Rose described it, is at least listenable. One can only be thankful that the original recording was made. (If only Mahler had lived long enough to record as a conductor) Oops, I think I just heard a portamento. From Toscanini??  I cut my teeth on Weingartner for Beethoven, and found Toscanini too fast. Yet I later espoused the HIP performances of Norrington, Gardiner, et al. One, hopefully, grows as life unfolds. The transfer, by the way, was also made by Marc Obert-Thorne. I see no need for intervention beyond this.
I am now playing the Pristine download (Mp3) of the Horenstein Bruckner Seventh. It still sounds like a 1928 recording— in fact the first electrical recording of the Seventh. Imagine all those 78s.  A quick check of Archivmusic and MDT show no listings for this recording. This may well be the only version of this available. The sound is somewhat cleaned up as for surface noise, and I am not aware of any “processing”. Sitting at the computer, I hear mono.  If I correctly recall Rose’s notes on the subject, his aim is to retrieve ambience, not left-right directionality. He may or may not have achieved this ambience. I am just thankful, as a Horenstein fan to have his (youthful) reading of my first and favourite Bruckner symphony available.
Digression Alert………..
Ambience can be a strange and subtle effect. I still recall first listening to my Mercury CD of the British Band Classics. I was in the listening chairs and remarked at the imaging. There were the thirty-six or so members of the Eastman Wind Ensemble down on the stage (balcony perspective) of the Eastman Theatre. Putting the disc away, I noticed the mention that it was MONO. But I remember mono Mercurys when first heard in the 50s were remarkable in that sense of sound moving through space towards the listener, especially on crescendoes. Imaging, in mono!………….Digression Ends
The second movement has started and the Wagner Tubas are quite audible. Strings sound natural, there is some deadened surface noise. This is not a modern recording obviously, but the realization is convincing. Now the Wagner Tubas and Bass tuba, I doubt the playback in 1928 would have given this. On to Mahler Four..This was from a live concert in1939 onto acetate disks. I have heard samples from the Philips re-issue, prior to downloading this (in Mp3). Of course they play up the Mengelberg/Mahler connection, and the fact that Mengelberg was using a score he had marked during Mahler’s rehearsals. Whatever!  This is the one I had heard featured on Henry [Fogel]’s program, and the first I had heard of Pristine. I have used them only since for a Hanson/Eastman Harris Third (I don’t think that Phillips got that far into the monos, before pulling the plug).
Basically, I am pragmatic about this. I am constantly amused by The Technological Imperative—If we can, we must — the best example being the Zenph “Ghosts”. What need was there for the Gould Goldbergs Redux?  I am happy with my Naxos Historical disc of this. I remember the 60s attempt to revive piano rolls, which always were fundamentally suspect, unless disc recordings of whatever sound quality were available for tempo and phrasing reference. The art of re-mastering old recording is as much art as science, as is live recording. The result is what counts.So I continue in my preference for Naxos Historical, who have hired the best for their efforts, (Marc Obert-Thorne and Wade Marsden, who also do work for Pristine), also Mike Dutton, and Testament.
Perhaps it is unusual in my generation— and for sure in subsequent generations— to be concerned about what went before one’s own appearance. I mentioned Weingartner as my first Beethoven experience. What I find unusual is that I never heard Fürtwangler until recently. On my computer are two versions of Mahler Four: the  Mengelberg; and the Fischer/Budapest Festival with the beauteous Miah Perssons (On CDs, Horenstein & Barbirolli).
to me, Robert (without comment)
For new readers, AM is editor Andrew Marshall, JEB, contributing editor John Edward Bain, and BO, contributing editor Bob Oxley
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One Response to “A Trialogue on Historical Recording Restoration by AM, JEB, & BO”

  1. Robert Auld c-us Says:

    In reply to AM: I have listened carefully to Andrew Rose’s restoration work, and I have experimented with using the Har-Bal equalizer in the way that Rose describes. With sufficient care, it is possible, in some cases, to get remarkable results. You may listen to an example on my web site:

    Given your comments, I am not sure you have listened to any of Andrew Rose’ work or tried to evaluate it fairly. My own evaluation tells me he is onto something, and you would do well to check it out.

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