| 
Theoretically, CD players should be able to perfectly correct errors
  up to 2.47 mm across. In practice we found some players capable of 
  correcting 2.0 mm errors. CD-CHECK simulates realistic errors of
  0.375, 0.750, 1.125 and 1.500 mm. In order to cope with manufacturing
  errors and dust, scratches and fingerprints CD or DVD player should
  be able to pass at least Check Level-2 with 0.375 mm errors. Our 
  recommendation will be to get a player which will pass at least 0.750 
  mm or 1.125 mm errors. You will find that there are many players which
  are only capable to play Check Level-1 or Check Level-2 on the CD-CHECK disc.
  And that is when they are new. With time their performance will dip
  below the acceptable level.
 
 
to evaluate existing CD, DVD and CD-ROM players for data loss 
CD players detorierate over time. Protect your audio investment by 
detecting pickup defects early. Use it to determine when pickup 
adjustments 
are needed. Use it to check the adjustment effectiveness. Test your player 
especially prior to warranty expiration. If you are a service shop technician 
use CD-CHECK to help you with the rapair process.
 
to determine if the laser lens needs cleaning 
     Dirt accumulates on laser lanses of CD, DVD and CD-ROM players and 
recorders. There are CD-based products that will clean dirty lenses. (Only 
high-quality products should be used since low quality products can damage the 
lens after repeated use.) Some cleaner manufacturers recommend cleaning the lens after 
every 8 hours of playback, which we consider unnecessary. CD-CHECK will 
determine whether the lens truly needs to be cleaned, saving it from 
potential abrasions caused by unnecessary - and repeated - cleaning. CD-CHECK 
can be also used after the cleaning process to check its effectiveness.
 
to evaluate the safety and effectiveness of sound-enhancing technologies
     Many gadgets and gizmos that enhance the sound of CDs/DVDs are very difficult to test objectively.
     Therefore, many evaluators rely on subjective audition tests, which can be very unreliable. Many of these
     sound enhancing technologies claim that they improve signals. Since they mostly affect only the digital
     signal, CD-CHECK can be used to evaluate them objectively and simply. If any of these technologies
     improve the playback of CD-CHECK's test signals, this clearly indicates that they reduce the number of
     errors generated, which in turn can lead to better sound quality. But, if no change is observed, it means
     that a given technology does not work in this particular instance.
 
     Sometimes these sound-enhancing technologies actually cause the sound to deteriorate. They can even
     harm a player's mechanical systems, which could lead to premature mechanical failure. Some reviewers
     will probably hear the difference, and might even prefer distorted and interpolated sound over the real
     thing. Internal tests at Digital Recordings and by our associates indicate that this may be the case with
     some technologies. But we prefer undistorted and faithful sound reproduction -- and we're sure that you
     do, too. With CD-CHECK, you can be sure that's what you're getting.
 |  | 
| Empower yourself with CD-CHECK ! |  
|  |  
| Do not expect manufacturers, sales people and audio magazines to represent 
YOUR interests ! 
Digital Recordings supplied the CD-CHECK disc, free 
of charge, 
to most of the audio magazines. Some are using the disc in their equipment 
reviews, others decided to ignore it and continue supplying you with false 
data regarding the CD and DVD players performance.
 
So, if you are looking for a player that offers 100% of music and not just an 
approximation you need CD-CHECK to test the player yourself.
 
Furthermore, you should remember that CD players vary in quality from sample 
to sample and from manufacturer to manufacturer. There are vast differences 
between players often not related to the price of the player. Crucial to this 
performance diffrence are the CD transport mechanisms. They vary in price 
from $15 to 
$250. Some manufacturers are trying to save money and some have inadequate 
test procedures and quality control. (Recently we heard of a $10,000 CD player 
from a reputable 
manufacturer poorly performing on the CD-CHECK disc.)
 
Make sure you are buying a player capable of reproducing 100% of music. Use 
CD-CHECK !
 |  
| List of audio magazines which have CD-CHECK disc(s): - "Absolute Sound"
 - "AUDIO"
 - "Audio Amateur"
 - "Audio Critic"
 - "Audio Electronics"
 - "Audio Ideas"
 - "Inner Ear"
 - "Recording"
 - "$ensable Sound"
 - "SoundStage!"
 - "Stereophile"
 - "Stereo Review"
 - "UHF"
 - "Ultimate Audio"
 - "What HI*FI ?"
 
 
List of some audio manufacturers who have CD-CHECK disc(s):
- Philips
 - SONY
 - JVC
 - Panasonics/Technics
 - AKG
 - KRELL
 - NAD
 - Oracle
 - NAGRA
 - ARCAM
 - Cello
 - Clover Systems
 - Hegel
 - Mark Levinson
 - Madrigal Labs
 - Harman International
 - Polyfusion Audio
 - Balanced Audio Technology
 
 |  |