Apple is accusing Sony of misleading consumers with its claims that its new 20GB Walkman is able to hold more songs than the 40GB iPod.

Apple vice president of hardware product marketing Greg Joswiak told MacCentral: "We thought it was time to help set the record straight. We're disappointed that Sony has chosen to mislead folks with a marketing gimmick – we just want to make sure customer have the information so they can make an apples to apples comparison, if you will."

Joswiak explained that Sony's compression system ATRAC3 compresses songs at 48Kbps (kilobits per second) while Apple's compression system offers 128Kbps. "48Kbps is nowhere near CD quality," he claimed.

Joswiak also claimed that Apple has always based its song count on the nearest to CD-quality compression available. "If we played the same trick as Sony and took it down to 64kbps, you could say the 20GB iPod could hold 10,000 songs. You could take it down to 16kbps – which is the lowest available to us like 48kbps is the lowest available to Sony – and we could say it holds 40,000 songs. That's something we would never claim because that's just not something a customer would do."

In a final dig at Sony, Joswiak said: "Certainly there is a belief that great brands will portray this honestly, as we've tried to do. Again, it's a little disappointing that Sony has chosen to do otherwise."