The Cd Story

The CD Story

by Marek Roland-Mieszkowski, Digital Recordings, August 1996

A Compact Disc (CD) was introduced on the market in 1982. I remember very vividly a sales person rubbing the disc against the counter and telling me that the laser disc is indestructible and will never skip or generate clicks, something that was so common and annoying, as we all know, on LP records.
My friend Pat who was one of the most prominent purists and audiophiles rejected the CD format as sounding unnatural and very brittle. You must understand: his audio system was very impressive. He had a very expensive turntable with an equally expensive cartridge. A signal was fed to an esoteric preamplifier with no tone controls (as a purist, my friend did not believe in them). The signal then went into an active 3-way crossover which was feeding eight esoteric amplifiers. Those in turn were feeding two huge speakers (stretching from the floor to the ceiling) which were custom built for about $30,000.
I have to admit that system sounded great and the speakers were among the best I have ever heard. I disagreed, however, with my friend about not using tone control, since as a sound engineer and acoustician I knew very well how poorly some of the records and CDs were recorded due to wrong equalization and use of multiple microphones.
I had to, however, agree with Pat on the brittle sound of the early CDs. In my opinion this was caused by wrong equalization and digital clipping distortion. SONY even later introduced a special analog soft-clipping front-end to its digital recorders to avoid digital hard clipping. Also, sound engineers since then became more experienced with recording in the digital domain. So, today many CDs sound good, some even exceptionally good.
But how good is the playback from a CD ? It turns out that sometimes it is not as great as we are lead to believe. Data (or music) is stored on a CD in a digital format as 0s and 1s. For the CD to faithfully reproduce the stored sound none of this data should be lost before being converted back to the analog world (by D/A converters). The problem is that often digital data is lost due to a dirty or faulty CD, dirty lens in a CD player, problem with tracking, motors, guides, digital circuitry in a CD player, etc. When data loss is greater than the error correction system's ability to compensate for it, some of the signal is lost. This in turn results in skipping, brittle sound from the CD, clicks and pops in the signal, etc. So, we are back to the LP problems !
I myself had a first-hand experience with these types of problems. Several years ago, being a very concerned listener, I bought a top-of-the-line CD player from a very well known manufacturer for about $1,000. I noticed that this player had a slightly brittle sound, which at that time I attributed to poor recording of my CDs. However, with time things got worse. The machine started to skip. Unfortunately, my warranty by that time had already expired. The local dealer was not able to fix the machine, so the CD player was sent, at a substantial expense to me, to another city, where the manufacturer has its headquarters and a better-equipped laboratory and repair shop. After a couple of weeks I received my CD player back. It turned out that certain mechanical parts were faulty causing the CD player to track improperly, and that caused the player to lose data. After this repair my machine started to work better, but it was still not perfect, skipping from time to time.
Recently, Digital Recordings produced a new product, the CD-CHECK compact disc, which allows for detection of problems with the laser, lens, tracking, digital circuitry, etc, in CD players and other digital equipment. I tested my CD player with CD-CHECK and as I suspected it only passed Check Level-1. I wish I had this CD when I was buying my CD player!
Having CD-CHECK and still experiencing problems with my machine, I took the player back to the local repair shop, gave the technician CD-CHECK and asked the shop to fix the machine so it would play test signals flawlessly. After replacing $100 worth of mechanical parts, they were not able to correct the problem. They suggested that I send my CD player to another city (again !) where the manufacturer has its main repair shop, at the expense to me of at least $150-$200. This time I decided to buy a new CD player instead. Equipped with CD-CHECK I am sure I can now choose a machine that will be free of the problems described above.
I already discovered that some CD players in audio stores have difficulties playing CD-CHECK test signals. As you may have guessed by now, the one I choose for myself will play these signals flawlessly .... good-bye poor quality and defective CD players !
P.S. Stay tuned for more information on my experience with shopping for a new CD player.

Update - August 1998
In August 1998 I bought a used Philips CDI 910 player. It passes Check Level-5, has no problems playing any discs, and it sounds great ! VICTORY AT LAST !

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