Slashdot Mirror
From the Higgs Boson Particle to Leadbelly
Roland Piquepaille writes "Physicists from the Lawrence Berkeley National Laboratory are using the same methods to search for the elusive Higgs Boson particle and to digitally restore audio recordings from the past. Berkeley Lab signed an agreement with the Library of Congress to digitize the many thousands of early blues or jazz recordings it has in its archives. And the results are spectacular. Compare for example, these two versions of "Good Bye Irene", before and after being optically reconstructed (WAV format, 18 and 19 seconds). This news release describes the method used by the physicists. This overview contains other details and extra references about this project." We also covered finding Higgs Boson recently as well.
1). It's "Ledbelly"
2). It's "Good Night Irene"
0 posts and it down to going at 6kbps.
Sure it'll be slashdoted soon.
Orignal & Digital version
This reminds me of this project (which has been Slashdotted before) which can be done with a home scanner. But this new Berkeley method is obviously much more advanced.
...and cleaning a record so that it can be played with a laser is far more damaging than playing it with a needle.
Besides the neat way the archiving is being done, this will help out the Library of Congress immensely in getting their archives digitized before the originals deteriorate to the point they cannot be archived at all. A few years ago, PBS (maybe on Nova) had a special about the digital restoration project at the Library of Congress. They were having to take special care to prioritize the works they wanted to save, as they didn't have enough manpower to digitize all of them before the original recordings completely rotted. Most of the recordings were one-of-a-kind, so much of the archives was expected to eventually be lost forever.
They also emphasized about how they wanted digital version of the original recording, with all of the noise, clicks, and dropouts intact. After all, they are digitally archiving what they have, not restoring it.
One of the biggest finds was an original recording of "This Land is Your Land" by Woody Guthrie with the following stanza intact:
Was a big high wall there that tried to stop me,
Was a great big sign that said, "Private Property,"
But on the other side, it didn't say nothing,
That side was made for you and me.
I believe it's a one-of-a-kind and it was found on accident, as the archives literally have dozens of different "This Land is Your Land" recordings and it had previously been digitized before this version was found.
Back in the good old days of vinyl records, RIAA Equalization was/is an industry standard for how music that is recorded on vinyl records is played back. The idea is to compensate for the fact that vinyl does not have a flat audio frequncy response.
The link above explains it much better (and in more detail) that I can.
\/Don
The LoC collection of American folk music was certainly one of the strangest ventures ever carried out by the US government. In a way, it paralleled the ancient Chinese venture that resulted in the Shih Ching (Book Of Odes). Both govs sent recording agents into the country with the directive to collect the songs of the people. The Chinese had only ink & paper (or whatever they used for paper circa 800 BC), while their US counterparts (beginning in the 1920s, I think) utilized their day's equivalent of direct-to-disk recording, i.e., big in-field acetate disc cutters with acoustic recording gear. For the most part these intrepid researchers are unknown, but they collected an incredible mass of disparate music. Black & white music from the deep South and the Appalachians, cowboy music from the plains states, music from native American tribes... The impression I have is that they were told something like "Go ye forth, collect their songs so we may know the mind of the the people". Well, that's what the Chinese collectors did anyway...
There are some well-known LoC recordings that have gained some fame, including a series of recordings by Leadbelly and an awesome set of music and reminiscences by Jelly Roll Morton. However, both those sets were recorded "in studio" and are not field recordings. They are magnificent though.
Btw, I should make special mention of the Lomax family. Father John and son Alan were responsible for some remarkable recordings, including the work by Leadbelly and Jelly Roll. Alan also made the earliest recordings of Muddy Waters and some excellent recordings of Son House while working for the LoC. John was something of a Texas cracker (check out his dialog with Willie McTell on the LoC recordings), but he was a brave man going into some of the places he visited. He also wrote a very weird account of his acquaintance with Leadbelly in a book he wrote about the great self-proclaimed King of the 12-string Guitar..
Some of the catalog has been available to the public for quite a while, but I doubt that catalog has listed anything close to the amount of material the LoC must have in their vaults. Those acetate masters won't last forever, and I'm glad to learn that an attempt will be made to save those recordings.
Btw, I doubt copyright is an issue with this material. Unless I'm mistaken I believe all of it is in the public domain now. Perhaps someone else can clarify ?
No recent US administration would dream of doing such a project now. They definitely would *not* want to do it to know the collective mind of the people...
WAV is not necessarily 16 bit. There are 8, 16, 24, and 32 bit WAVs (that I've seen) and I suspect the format can handle higher bitdepths. I know it can handle 192/24.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
Whether you like rock, blues, jazz or R&B they all have their roots in the early part of the 20th century among the poor black population in the southern parts of America. A big part of that history is already lost for ever.
I am a big fan of early blues. My favourites are Leadbelly, Blind Lemon Jefferson and Robert Jordan
Indecently, Robert Jordan is the guy who supposedly sold his soul to the devil one night at the crossroads in exchange for his guitar playing skills. This story gave rise to the whole blues, rock etc. comes from the devil story.
You can find a lot of their music on p2p networks - it's worth checking out. You'll be surprised how many songs you recognise - they have been copied and covered so many times.
siener's youtube channel
Removing the noise is only the first step.
A complete restoration would compensate for the transfer functions of the microphone and other recording equipment used for the particular recording. Need to archive and preserve all the recording equipment also!
Basically, it involves the master being equalised with the bass rolled-off by (up to 20dB) and the treble boosted by a similar amount. On playback, the 'phono' input on your amplifier ampplies inverse EQ to re-create the original signal.
The reasons are two-fold:
The initial treble emphasis followed by roll-off reduces the contribution of record surface noise from the mechanical transcribing.
The bass rolloff means that the excurions required by the cutter (and the sylus in playback) are kept within reasonable limits - and enable closer groove spacing, allowing a useful recording time. Note there's a direct tradeoff in LP mastering between playback time per side and sound quality, depending on how 'hot' the signal to be cut - more groove excursion requires more space.
The RIAA's contribution was to declare a standard for the EQ curves, when before c.1948 each record company would do more-or-less its own thing.
We did this in a signal processing project, where we scanned old recordings and extracted the music. We tried Wiener fitlerning, but settled on spectral subtraction. Listen in. The problem is (as an anonymous coward so wisely pointed out) that you inevitably remove some of the wanted signal as well.
"Stop failing the Turing test!" -- Dilbert
It wasn't "Good Night, Irene", it was "I'll Take You Home Again Kathleen". By Lt. Kevin Riley. In the episode, "The Naked Time".
The only reason we have the rights we have is that people just like us died to gain those rights. -- Cheerio Boy
Result sound viewed with -42 threshold
Result sound viewed with -60 threshold
Result sound viewed with -42 threshold
And the following image is a spectrogram of the original "Goodbye Irene" file:
Original sound viewed with -42 threshold
Each of these spectrograms was computed using 1024 point Discrete Fourier Transforms with a factor of 8 overlap. The dimensions of the images are unlabeled, but provide a frequency range of 0Hz - 22050Hz along the vertical axis, and approximately 344 horizontal pixels represent one second of time. Darkness represents the magnitude of the signal at a particular measured frequency.
With significant interest, I can perhaps label these axes for easier reading. Simply keep in mind that the top of the vertical dimension represents 22050 Hz.
Given the sound quality of the result sound provided, utilizing 16-bit quantization with a sampling rate of 44.1Khz is more than adequate. But while the result is promising, it is hardly archival quality in my opinion, due to the obvious digital artifacts.
The dynamic range of this particular music is confined by musical convention and the microphone technology available for the recording. The theoretical 96dB of dynamic range availed by 16-bit quantization is more than sufficient to represent the dynamic range of this particular music (and many others) recorded with similarly early microphony and disc-cutting technology.
The frequency range of the music does not appear (in this result mind you) to have significant musical information above an approximate (but conservative) 11000 Hz. The frequency range availed by a sampling frequency of 44.1 KHz is more than adequate to quite faithfully represent this music. To significantly reduce the broadband pops and crackles in the recording, high frequency information is lost. Further, the recording technology available at the time probably could not accurately transduce such frequencies from the original performance either.
The spectrogram reveals that the undulating noise in the result sound occurs at a nearly precise 5Hz. It also reveals that this "noise" is obviously an artifact of the restoration process; it really isn't noise, but the result of a time-varying filter which cuts gaussian lobes into the spectrum of the music from approximately 4000Hz to 9200Hz in a manner somewhat a kin to a wah wah pedal. The lobes can be seen clearly in all of the spectrograms I provided, but they appear more stark as the peak threshold of the spectral plots decrease. Their duration is quite close to .05 seconds.
In my opinion, archives should preserve physical recording media as long as possible to allow transduction techniques to mature. I find the 5Hz filtering artifact present in this result to make the current state of this particular optical transduction process unacceptable for archiving. It would be a shame to replace physical media with music colored with such avoidable artifacts. I am sure that such artifacts can be alleviated and that optical scanning of phonograph records (discs and cylinders) has great promise as a transduction technique.
I don't get it. Why do people at Berkeley need a grant to re-invent technology that has already been comercialized by people from Stanford in the early 80's? http://www.smartdev.com/LT/laserturntable.html
In the 1860s, a man went around "recording" things with glass disc coated with carbon black and a needle attached to a megaphone that scratched the carbon off when someone spoke. They were curiosity items, since there was no way of playing them back, but the inventor got some famous people, including President Lincoln, to make them. This technology could let us hear them. Also, laser technology for reading LPs was available at the very end of the LP era, and is still being sold, at astronomical prices, today ($8-14K). See http://www.elpj.com/ I've read that it's not very good at eliminating tics and scratches.
Totally agree. Looking at the separate files in Cool Edit, you can easily see that in the "new and improved" version everything above 8000 Hz has been almost completely removed. The weird pulsating hiss is at this 'cut off point'. The only good thing in the new version is an apparently better recording of the high volume parts (less clipping-like static). Of course, in doing so, it lost all the high end and introduced (it can only be a digital artifact) a pulsating hiss. Maybe their technique is good as the only option to play unplayable records, but for restoration purposes, it is a joke... come to think of it, I'm going to make a joke about it in the main thread.