Some examples:
Here's a graphical level display of a small part of a Sepultura song: mind the clipped parts: the waveform is chopped of several times! The top graphic is the left channnel, the botton graphic represents the right channel. The thick lines indicate 0-level, the thin lines indicate the maximum level.

This is about CD sound, so you'll have to listen to the CD itself to heart the result. To give you an example, i've put a short cut of this song here for download (the file size is 1003KB in wav format). It's a digital copy of the CD, so the sound quality depends only on the quality of your soundcard. The cracking you'll hear is not generated by your PC, this the recording itself. I like their music, but can you believe this is the sound of a mega-group with a huge recording budget?
Because of copyrights and diskspace limits I cannot let you hear complete songs. If you don't succeed in downloading the file, I can also mail it to you.


Below are some randomly chosen examples of poor-sounding CD's, they're not the only ones!

These are the sound quality ratings I use: From bad to good: AM radio quality (really bad) < FM radio quality (acceptible on normal stereo systems) < Hi-fi quality (good sound on a decent stereo, but no improvement when listened to on a perfect system) < High End quality (the better your equipment, the better this CD sounds). To stress it again: it's not because you have a very good sound-system that you will have better sound.

• Metallica 'Load':
  
  Unstable sound because of too heavy compression. Sound quality rating: almost hi-fi.
  
  
• Portishead 'portishead':
  
  Huge amounts of clipped audio. OK, I know hey sampled records and added distortion to their record, but I can hear a difference between wanted (analog) and unwanted (digital) distortion! (listen to song 2: great song, horrible soundquality!). The soundbalance of this record is distorted: the level of deep bass and very high frequency is much lower than the mid-frequencies, thanks to too loud mastering. Sound quality rating: worse than FM radio quality



• Depeche Mode 'Ultra':
  
  Idem dito. Sound quality rating: FM radio quality



• Madonna:'Ray of light':
  
  This is another amazing example of an expensive album with horrible sound quality: the high frequencies (most audible on the rythm sounds) are cut-off! I even switched off the 'source direct' on my amplifier so I could boost the high frequencies + 6 dB to make the sound acceptible... Sound quality rating: AM radio quality



• Hooverphonic: Blue Wonder Power Milk:
  

  <- Histogram of loudest part of song. Most appearing level is -10 dB

  
  It seems that only a record mastered by Bob Ludwig can sound OK. Sound quality rating: Hi-fi. Louder than this with decent sound isn't possible. But "decent" still isn't the best... E.g: when the bassdrum on the first track starts, you can hear the compressor...



• Novastar: 'Novastar': very good music, horrible sound quality. MUCH too loud. AM quality.



• Das pop: 'I love das pop":
  
  Also brilliant songs, but mastered much too loud. I sent then a mail (May 2002), I'm still waiting for an answer... A bit better than the Novastar CD, quality = almost FM radio.



• Madonna: 'Music':
  
  Hey!, somebody listened! This CD sounds better than the previous one! Somewhere between HiFi and High-End. Makes me feel better already!



• Kolk: 'Nachtschade':
  

  Kolk: UMA

  <- Histogram of loudest part of song. See how the soundlevel is forced to the maximum. Most appearing level is -8 dB.

  
  Another much too loud belgian CD. Just look at the waveforms.
  Complete song:
  
  
  
  Below is a small detail of the same song: as you can see the waveform isn't clipped as the Sepultura song. 'Thanks' to extreme limiting the wave isn't cliping anymore, but is almost completely straight at the extreme values. See the comments page for a CD-Image 'limiting' comparison.
  
  
  

Pixies: Gauge away

<- Histogram of loudest part of song. Most appearing level is -17 dB"