Everything I Need to Know I Learned From the Hubble Telescope

Should a recording document reality as faithfully as possible, or should it improve upon or somehow transcend the music it records? Both, actually.

[Image Credit NASA, ESA, and the Hubble Heritage Team STScI/AURA)-ESA/Hubble Collaboration. Acknowledgement: B. Whitmore ( Space Telescope Science Institute) and James Long (ESA/Hubble).]

The topic is very much in the news. Organizations like Harvard University and public radio station WDET-FM Detroit have publicized plans to digitize their vast archives of interviews and live performances, both for preservation and for cloud accessibility. The Harvard archives include rarities like the first appearances of Joan Baez at Club 47 in Boston, so it is important to do right by the material. But what exactly constitutes a high-quality digital audio preservation process?

Consider the image from the Hubble Space Telescope above, showing the slow collision of two galaxies producing super star clusters. It's spellbinding, dramatic, but it isn't real. Space doesn't look like this.

Hubble images are triumphs of sensor fusion. They are made, not born. Images must be woven together using the incoming data from cameras in many different spectral bands, cleaned up and given colors that bring out features that eyes would otherwise miss. The images illustrate the wonders of the universe rather than documenting them.

[I wonder if the sound subjectivists who believe that lossy compressed audio is “just fine” also dismiss space exploration with sophisticated instruments, because they can see stars “just fine” with the naked eye.]

It may seem quite a leap, but a strong analogy exists between the production process for a Hubble image and a high-quality digital restoration process for analog source material. There are three fundamental steps in both:

• Data Collection. The dramatic Hubble images have their source in high-resolution instrument data; do no less with your source audio.
• Sensor Fusion. Use software tools to analyse the audio from multiple perpectives to execute operations to improve audio quality.
• Presentation. Render the results in formats accessible to the intended audience(s).

When the process is complete, two products have been created. First, there is an archival recording that faithfully transfers the original analog recording, in all its flaws, to digital form. Also, there is a restored image of that recording as processed sound files that transcend the moment to reveal what may not have been originally apparent to the naked ear.

But how do you design these steps to achieve a high-quality result? There are five fundamentals:

• Accuracy, with regard to the source material
• Appropriateness and Adequacy, with regard to your processes
• Consistency and Explicitness, with regard to your execution

In an upcoming three-part series, we’ll examine how to stay true to the five fundamentals in your project. Stay tuned.

[Originally published 2-February-2012. Revised and expanded.]

            Vinyl-to-Digital Restoration #15            



Artist: Pink Floyd
Title: The Dark Side of the Moon
Genre: Rock
Year: 1973



What other title could be more appropriate to discuss? DSotM presents a presentation challenge due to the extensive use of crossfades between tracks, making it hard to identify the instant where one track ends and the next one begins. They slowly collide with each other in passing. As with live albums, you'll be glad to have accurate high resolution sound data when confronted with a crossfade to zoom way in to make a precise cut at your decision point.

© 2012 Thomas G. Dennehy. All rights reserved.


The Voices of the Little Monsters Were Exceedingly Unpleasant

I think it is a good day in the audio restoration mines when I am able to digitally remove surface noise from an ephemeralized LP that has seen better days. But you have to stand in awe at scientists who can digitize audio from priceless relics — many of them too damaged to play — without actually playing them.

[Photo credit: edisontinfoil.com]

Among the twenty-five 2011 selections for the Library of Congress National Recording Registry of
 "culturally, historically, or aesthetically significant" recordings is an 1888 prototype tin sound cylinder for an Edison Talking Doll. (See above. The tiny phonograph was actually housed inside the doll.) It is a historic artifact on many fronts: the earliest-known commercial sound recording, the first children's recording, and quite possibly the first recording to be made by someone paid to perform for a sound recording (an anonymous Edison employee reciting the first two lines of  "Twinkle, Twinkle, Little Star.")

But, until recently, it was not an audio artifact, rendered silent due to its poor condition (see photo, at right). Technology developed by the Lawrence Berkeley Laboratory under funding from the Library of Congress, Department of Energy, and others enabled the deformed cylinder (3" in diameter and 5/8" wide) to be "played" without physical contact using three-dimensional scanning and digital mapping tools to capture sound.

At the risk of gross oversimplification, the process is as follows. A large number of appropriately magnified 2D or 3D sequential digital images of a grooved surface are acquired. Typical resolution is in the sub-micron (< 1/1000th mm) range. Image analysis methods can then be applied to model the local groove shape. Using these models it is possible to calculate the motion a stylus would have made when it passed along these grooves, producing a reference sound file. The reference file can then be post-processed if desired using available audio engineering software tools. A technical presentation on the methods with several restoration examples is available from LBL.

With its audio liberated and preserved by this technology, the Edison Talking Doll cylinder could take its rightful place in the National Recording Registry. Give a listen.

Among the reasons the cylinder is such a rarity is that the Edison Talking Doll was an utter failure in the marketplace. Few were sold; production ceased after only a few weeks. The toy was doomed by some combination of its high cost (two weeks' salary for the average parent; think about that in today's dollars), difficulty to operate, suceptibility to breakage, and fright factor to children. If all that weren't enough, Thomas Edison is said to have admitted, "The voices of the little monsters were exceedingly unpleasant to hear." Not exactly Tickle Me Elmo.


            Vinyl-to-Digital Restoration #35            

Artist: David Bowie

Title: Scary Monsters
Genre: Rock
Year: 1980



From December 25, 1980 Rolling Stone: Where do you go when hope is gone? The artist's next album may see him questing, but on Scary Monsters, he's settling old scores. Slowly, brutally and with a savage, satisfying crunch, David Bowie eats his young.


© 2012 Thomas G. Dennehy. All rights reserved.