Apple has responded to Sony’s claims that its new 20GB Network Walkman music player can hold 13,000 high-quality songs. The Wall Street Journal reports (paid subscription required): “In a statement, Apple said Sony isn’t accurately depicting the song capacity of its new 20GB Network Walkman. While Sony says the device can hold 13,000 tracks, Apple alleges that the Japanese electronics giant, in calculating the storage capacity of the Network Walkman, is using songs that are compressed into digital files of inferior fidelity to those that Apple uses to calculate how many songs the iPod can hold. As a result, Apple posits, Sony’s Walkman actually holds only 4,800 songs that have been compressed into a higher quality format.”