Monday, September 24, 2012

Fast is Fine, But Accuracy is Everything

Previously we proposed there are five fundamentals of high-quality digital sound archiving and preservation for analog source material: accuracy, adequacy, appropriateness, consistency, and explicitness.

Today we tackle the first fundamental, accuracy (with regard to the source).

Consider this. Carole King's The Legendary Demos is now available in 24-bit/96kHz high definition. Demos. In high-def. Does that make any sense? Actually, it makes perfect sense, and illustrates the importance of accuracy.

Demos, as you probably know, are recordings of stripped-down arrangements songwriters use to "pitch" material — to producers, bandmates, potential clients. A promise of a song rather than the song itself. Neither professionally recorded nor mastered, the audio quality of a demo varies widely. And great songwriters are not always great performers (with notable exceptions).

The material on The Legendary Demos is true to the form. Many of the tracks sound as if they are simply Ms. King at the piano in her office. Recorded on 60s vintage analog equipment, the sound level is uneven, the piano not balanced with the vocal (the piano perhaps unmiked). So why go high-def?

The first reason is simply to master the material for release to give it as much polish as possible. (It sounds better here than on what may have been the original tapes aired during an April 2012 Fresh Air interview with Ms. King). Second and more importantly, these recordings document the creative process which produced songs that went on to become big hits. How does one preserve such moments for posterity so they are not lost or forgotten?

The International Association of Sound and Audiovisual Archives (IASA) "Guidelines on the Production and Preservation of Digital Audio Objects" offers these recommendations:
  • Sampling rate. When producing digital copies of analogue material IASA recommends a minimum sampling rate of 48 kHz for any material. The unintended and undesirable artefacts in a recording are also part of the sound document [and] must be preserved with utmost accuracy. For certain signals and some types of noise, sampling rates in excess of 48 kHz may be advantageous. IASA recommends 96 kHz as a higher sampling rate, though this is intended only as a guide, not an upper limit.
  • Bit depth. IASA recommends an encoding rate of at least 24 bit to capture all analogue materials. For audio digital-original items, the bit depth of the storage technology should at least equal that of the original item. It is important that care is taken in recording to ensure that the transfer process takes advantage of the full dynamic range.
Record analog source material for digital archiving with as many bits as you can muster. Preserve numeric precision (and hence dynamic range) in the audio processing pipeline. Establish and follow a plan that preserves the accuracy of the material presented.

[Originally published 10-May-2012. Revised and expanded.]

             Vinyl-to-Digital Restoration #32            

Artist: Carole King
Title: Tapestry
Genre: Pop
Year: 1971

If you are of a certain age, this is the album your sister and every woman you ever dated (my wife included) had in her collection . At one time, the best selling album in history, and Carole King the only female performer to win four GRAMMY® awards in one year. Legendary.

© 2012 Thomas G. Dennehy. All rights reserved.

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.

Sunday, September 9, 2012

What If Your Cloud Suddenly Vanished?

You have abandoned music possession and are now completely dependent on streaming services in the cloud to deliver their vast-but-low-bit-rate song libraries for your listening enjoyment. Are you prepared for the day when your cloud, or any other cloud, may no longer be there? From all indications, that day may be inevitable.

The most popular streaming services, Pandora and Spotify, have unsustainable business models. If these two pioneering giants can't survive in the long run, what chance does any other service have? Maybe music possession isn't as quaintly 20th Century as pundits would have you believe.

Pandora, which had its IPO in 2011, has never been profitable. Its revenues are growing steadily, but so are its losses. For the quarter ending July 30, 2012 revenue was up more than 50% year-to-year to $101.3M, but its quarterly losses of $5.4M were 3x last year's. According to filings in Spotify's home country of Luxembourg, the company lost $57M on $236M in revenue for fiscal year 2011. The red ink cannot continue indefinitely.

"Cost of sales" is the highest contributing factor to the sustained losses. Pandora operates as a limited-play radio service and does not have to negotiate royalty deals with individual labels. Still, last year the company paid 54% of its revenue out in royalites under the provision of federal copyright law that lets it use (almost) any song. Spotify operates as an unlimited on-demand music service and negotiates directly with labels and publishers for the songs it makes available, paying a staggering 97% of its revenue on licensing fees and distribution costs. (Source: NY Times.)

To climb out of its hole, Pandora is lobbying Congress for a copyright license deal more aligned with satellite radio and cable outlets, the so-called Internet Radio Fairness Act. The licensing rate for satellite is set at 7.5% of gross revenue. Cable music services pay 15% of gross revenue. On the other hand, Pandora pays 2 cents per hour for the more than one billion streaming-hours it runs per month. (Source: LA Times.) Music publishers, becoming more dependent on revenue from streaming as CD sales continue their decline, oppose any change. Additionally, statutory licensing is unique to the USA; overseas growth for Pandora will be hard to achieve without similar license deals in other countries.

To reverse its current fortunes, Spotify faces the daunting task of trying to make monopoly economics work. If the EMI sale closes, there will only be only three major music labels. As explained by Michael Robertson of, the jaw-dropping secret licensing demands of record label monopolies would not be tolerated in any other industry as they "crush innovation, as well as any hope of profitiability." Since failure to reach a deal with any of the labels would put a huge hole in Spotify's catalog, the company really has no choice but to concede to industry demands.

Listeners have embraced streaming audio services in the cloud. At least 33 million people have tried Spotify, more than 150 million have registered for Pandora. But maybe now is not the time to abandon music possession completely in favor of streaming; the current cost structure of the industry is unsustainable. Are you prepared for the day when there is nothing but blue sky where your cloud used to be?

            Vinyl-to-Digital Restoration #42             

Artist: Willie Nelson
Title: Stardust
Genre: Country
Year: 1978

Willie Nelson has never been one to do the safe or expected, and this Booker T. Jones-produced album of pop "standards" from the '30s and '40s certainly fits the profile. The success of Stardust paved the way for the late-career standards album of virtually any singer you can name. I had never heard more than a couple lines from Irving Berlin's cloud-free "Blue Skies" (via montage in the movie White Christmas) until picking up this album as my introduction to Mr. Nelson's work.

© 2012 Thomas G. Dennehy. All rights reserved.