Positive Feedback ISSUE 58
november/december 2011

 

 

Has the Time Come for a Pure Analog Laser-Read Format?
by Teresa Goodwin

 

Now that high resolution PCM and DSD are available on the computer, the one thing computers cannot do is playback analog in its pure form.

With the revival and popularity of analog LPs and those pricey 2 Track 15 IPS prerecorded reel to reel tapes from the Tape Project, isn't it about time we had a format that offered all the sonic advantages of a pure analog format with none of the disadvantages, such as tape hiss, surface noise, pops and ticks, and other extraneous noises? Inventor George Mann first conceptualized such a format back in December 1974.

The high resolution digital formats sometimes do an excellent job of imitating analog, however nothing sounds more analog than real analog formats as they bypass the analog to digital conversion upon recording and the digital to analog conversion upon playback. The whole idea of changing analog to digital in recording is an effort to eliminate the limitations of the recording medium, such as tape hiss, overload compression, wow and flutter, etc. Suppose instead of spending all the millions of dollars in almost three decades of trying to make digital sound more like analog that this money was actually spent to perfect analog, with something along the lines of George Mann's laser read analog format.

If analog is perfected, digital becomes an unnecessary inter-step. Even the highest resolution digital recordings degrade the original analog musical event, even if by a small amount. The original analog sound produced by instruments and voices including the ambiance of the recording site is what is we want to capture. In the digital domain DSD seems to degrade the least losing only the sharpest and fastest transient attacks and a small amount of ambiance and air. However if we had optical analog master recorders coupled with an optical analog playback format we could capture the original sound in all its glory with no conversion away from analog ever.

George Mann invented a full-spectrum, optical analog laser-read format. It was 12 inches in size like the analog LP and played 30 minutes per side in 2 channel stereo and looks like those 12 inch Video LaserDiscs of old. It is totally different than the ELP turntable which is designed to play vinyl LPs with a laser along with all the extraneous noises of traditional LP playback. Mann's optical analog laser-read format is instead a double-sided 12 inch disc constructed of two single-sided aluminum discs layered in plastic using a special laser to read the modulations. It is said to be sonically superior to the best LPs without the drawbacks of a physical contact medium.

I like the 12-inch size because of the superior large cover design artwork and easier to read liner notes especially in those beautiful gatefold LP jackets. One does need to take precautions to keep the album covers looking like new by keeping them vertical with no lean and in plastic outer sleeves. The packaging for five inch discs is just to small in my opinion. To have an optical analog format with no surface noise, scratches and ticks would be a dream come true.

More details on George Mann's optical analog laser-read format and some of his other inventions can be read in my 2006 interview with him from my eBook "An Analog Lovers Survival Guide" which I recently added to my blog. http://analog-lovers.blogspot.com/2011/10/george-mann-interview-from-analog.html

I wish the audio revolution had stayed tubed and analog. I miss going to the hardware store to test my tubes. I miss browsing and buying new pre-recorded reel to reel tapes at Muntz Stereo Tape stores and LPs at record and department stores.

How much different would the world be if Philips had picked George Mann's optical-read analog format instead of the Sony digital one for the new early 1980's optical music format called CD. No going from analog to digital and back to analog to hear the music, just analog all the way from microphone to speakers. 

Mike Spitz, owner of both ATR Services, which is refurbishing vintage analog decks, and ATR Magnetics, which is manufacturing tape for them, says business has boomed in recent months.

"Tape is now the holy grail for musicians," he says, welcomed by both industry veterans who miss the format's sine-wave warmth and by indie twenty-somethings who are experiencing full bandwidth after a lifetime of listening to highly compressed MP3s.

Analog's attraction lies in its ultra-high resolution capability, Spitz explains. Direct Stream Digital (DSD), the high-resolution digital disc format Sony used for its audiophile SACD format, is capable of 2.884,000 transitions per track per second, but a high-quality mastering tape contains approximately 80 million transitions per track second. "And that's just for 1/4-inch two-track tape running at 15 IPS," says Spitz. "The resolution goes up substantially with wider tracks and higher (tape) speeds."

See "Analog recording makes a comeback" http://www.variety.com/article/VR1118029668

Music is Analog

 

In the rather simplistic drawing above we see that the top "analog" waveform is smooth while the "digital" representation shows that while it follows the general path of the waveform, relying on finite slices of information, it has critical missing musical information. I will explain why this occurs in everyday non-technical language.

Definitions

Analog - relating to or using signals or information represented by a continuously variable physical quantity such as spatial position or voltage. Often contrasted with digital.

Digital - relating to or using signals or information represented by discrete values (digits) of a physical quantity, such as voltage or magnetic polarization, to represent arithmetic numbers or approximations to numbers from a continuum or logical expressions and variables. Often contrasted with analog.

Analog versus digital music

Analog recordings offers a comfort level and the ability to draw one into the music, not just how music sounds but also how one relates the music and the performers. The best analog is beautiful, comfortable and very realistic, full of the emotions of the players and the uncanny presence of their instruments within the original recording space transported into one's room.

Traditional analog formats while pleasing musically and sonically are plagued with varying degrees of non-musical sounds such as tape hiss and surface noise and can be difficult to play, thus the invention of digital recording and digital formats. By representing the music as mathematical values (1's and 0's) only the music is recorded and the physical properties of the recording medium ignored thus eliminating wow and flutter, tape hiss and other artifacts of the physical medium that the digits are recorded on.

The problem is since digital is not continuous like analog it must be chopped up into pieces and sampled, the more samples per second the closer it sounds to analog. In addition human beings can hear musical events as quick as two millionths of a second in duration, this is referred to as transient response.

With enough samples per second, such as in DSD's 2,822,400 the transient response is fast enough that is the ear is fooled into believing the music is continuous and analog-like. However the CD format is clearly not fast enough, thus the resulting music often sounds cold, analytical and strident as our ears attempt to fill in the missing information.

It is time that the powers that be take a serious look at George Mann's full-spectrum, optical analog laser-read format. While the original 12 inch proposed disc using a red laser could play up to 30 minutes per side of high resolution 2 channel stereo analog audio, by using a blue laser it might be possible to have high resolution multichannel analog audio as well.

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