Sunday, September 16, 2012

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.

1 comment:

  1. Very good analogy. I've long argued that Hi-Res music files allow for better 'focus' and what better way to present that idea? Nice one.