CD Sound Quality

Anita Cerquetti on Bel Canto Society’s Ernani CD:

“I’ve heard this performance on three different CD labels, Melodram, Myto and Bel Canto Society. The Bel Canto version has the best sound, and it is the one I give to people when I want them to know what I sounded like.”—Anita Cerquetti, Rome, Italy

Why Ours Are the Best-Sounding CDs of Historical Performances

The contents of the Ernani, Tosca, Gioconda and Björling Trovatore CDs were transferred from analog sources using the improved high-resolution technology called DSD (Direct Stream Digital). DSD operates at one bit and 2,822,400 samples per second. The result sounds more like analog than conversions using Pulse Code Modulation technology (even at the emerging PCM standard of 24 bits and 96 kilohertz) because it creates fewer digital artifacts, such as glassiness, glare and harshness. CDs made from DSD conversions sound better than other CDs, so I’m able to listen to them hour after hour without audio fatigue.

All PCM technology incorporates filters that chop off high frequencies beyond the range of human hearing. Moreover, most PCM incorporates filters that “decimate” the sound into 8, 16, 20 or 24 bits, which then must be “requantized.” All this causes most digital artifacts. DSD is better in part because it has no filters. DSD also conveys more sonic detail than PCM conversions. (To judge from our playback equipment, a PCM converter called the Prism conveys soft overtones and acoustic ambience slightly better than DSD but suffers a little bit from digital artifacts. On balance I prefer DSD.) With DSD conversions, virtually all digital artifacts you may hear are added by your CD player.

Mastering is by A. T. Michael MacDonald and Rich Lamb of AlgoRhythms, NYC.

Speed, Pitch, Tone Quality, “Feel”

The speed of a record affects not only musical pitch but also tone quality (not to mention the “feel” of a singer’s voice in the listener’s own throat). Most CDs reproduce historical recordings made on the European continent off speed—including all CDs that have been produced in America and Britain. Ours are the only exceptions! Here’s why:

  1. Since the 1890s the tuning pitch in the U.S. and the U.K. has been A=439 or A=440 cycles per second (hertz), with few examples to the contrary (except for early-music specialists).
  2. An international conference on pitch in 1939 endorsed the use of A=440 as have subsequent conferences.
  3. American and British record companies have wrongly assumed that European countries adhered to this standard.
  4. When these companies have pitched records at all, they have tried to make them play at A=440.
  5. When record companies everywhere have pitched records, they have failed to take into account that pitch rises by as much as five hertz as instruments heat up during performance and that pitch also rises during agitated or emotional passages.

I’ve published six articles on the history of the tuning pitch. Much of my theoretical knowledge has been confirmed by years of working with film and video. (Video speed almost invariably is reliable, enabling one to judge questions of tuning more accurately than with older records and tapes.) I have sensitized myself to distinguish between pitch rises caused by inconstant tape recorders and the like and those caused by emotional performances. (The former I regiment, the latter I leave alone.) Lastly, I suppose that my “feel” for correct playback speed for a voice probably is more acute than that of non-singers.

Working with instrumentalists, I arrive at pitching decisions only after research about the tuning pitch used for the performance plus many, many hours of experimentation with different speeds.

The drawback to all the above—experimenting with different analog-to-digital converters, slaving with colleagues over matters of pitch, etc.—is that it’s time consuming and expensive to the point that a company required to turn a profit would find it out of the question. We sometimes graduate pitch adjustments in increments as small as 1/100th of a percent.

For more on pitch, see three articles in Opera Fanatic magazine (not the catalog), Issue 3, 1989, also my pitch articles in the January 3, 1987 issue of Opera News and the Fall, 1988 issue of the Italian magazine Professione Musica.

Cleaning Up Pops, Clicks and Scratches

In the Björling Trovatore (#5000) transfer, we removed more than 900 clicks, crackles, scratches. Most other labels remove similar noises. But BCS, along with only a handful of other CD producers, cleans these defects one at a time. Most producers are content to erase clicks, etc. the easier way—in one swoop. This method, however, sometimes dulls the attack of certain notes. Percussion instruments are among the first to suffer, as do, sometimes, the consonants d and t. Carried out on a case-by-case basis, de-clicking, etc. can be accomplished without impairing the musical signal (unlike de-hissing and de-humming; see the discussion of CD #5012, the Corelli Trovatore).—Stefan Zucker

Why We Are Releasing CDs—Finally

I used to issue LPs—one, Rossini’s Rivals, is still in the catalog—but waited for digital technology to improve before issuing CDs. I kept acquiring analog source tapes, however. By 1993 digital improved somewhat, and I began experimenting with it. I listened to various high-end PCM converters to compare their sound quality. In 1999 I even sent master CDs for #5012, Il trovatore, to a replicator—but then canceled the production order because I felt the sound wasn’t quite good enough.

In early 2000 I tried the latest 24 bit/96 khz version of a converter called the Prism. It yields a more detailed sound and doesn’t compromise sonic “bloom.” With it I finally felt able to go ahead with the Trovatore. We had to rework it from scratch.

Later I found my way to DSD. Its inventor, Ed Meitner, a Viennese living in Calgary, is now providing Sony and Philips with the technology.

Both Prism and DSD yield sound that is significantly better than anything else digital to date. No one else is yet using either converter to make opera CDs of any kind—let alone of historical material.—SZ

Inventor Ed Meitner, rescuer of digital sound


BCS’s digital conversion process, Direct Stream Digital, was pioneered by Edmund Meitner, who is also providing converters to Sony, Philips and Telarc. He has designed an audiophile CD player, a turntable, a tuner, a preamplifier and power amplifiers as well as IDAT and BiDAT digital-to-analog audio converters. Meitner identified a cause of digital-sound degradation, phase jitter (involving timing errors), introduced a test instrument, the LIM detector, to measure it and published an article about it in The Journal of the Audio Engineering Society. He owns a number of patents in the field of audio electronics and heads EMM Labs.