MP3 players: iPod tips & tricks...feel free to contribute
everyone agrees, the iPod EQ presets is a joke, distort/crackling very badly when enabled.so i found some useful information from this article...http://www.dapreview.net/content.php?article.133"
All mp3 files have a default volume tag of around 95 to 105dB (decibels - a unit of loudness). When the iPod plays at this output volume, distortion does not occur. When you boost the iPod's bass however, with the equalizer, you are increasing the volume of the lower frequencies past this value (in order to make them more prominent amongst the other frequencies of the sound), and this, in turn, causes clipping and distortion. Basically, the iPod's amp is trying to output a volume that is greater than its inbuilt volume limit - so it serves crackling. By using MP3Gain to reduce the volume tag of your mp3 files to around 89dB, we can leave some headroom to further boost some frequencies without overdriving the iPod's amplifier."