Seven companiesCasio, Hitachi, Kyocera, Sanyo, Sharp, Sony Ericsson and Toshibawill supply the 12 models.
"We aim at high sound quality that surpasses portable audio players," said Masahiro Inoue, associate senior vice president in charge of KDDI's Service & Product Planning Division.
Meanwhile, KDDI's Mobile Number Portability system, slated for introduction Oct. 24, will let users keep the same telephone number when they switch carriers.
KDDI started a music download service in November 2004 based on a CDMA 1x WIN connection at 24 Mbits/second. Most of KDDI's "au" handsets can also carry audio ripped from CDs on PCs.
"Many people have grown accustomed to using the au phones to listen to music. Our next step is to provide higher sound quality," said Inoue.
Toward that end, partner Yamaha Corp. developed a sound generator chip that integrates the DiMagic Bandwidth Extender (DBEX) function from DiMagic, a Tokyo venture company specializing in virtual 3-D sound processing. DBEX restores the high-frequency range and the minute elements in the midrange that are lost when the original sound is compressed.
Yamaha supplied the chip and collaborated with KDDI in tuning the acoustic performance of the handsets, from the sound generator to the speaker and earphones. Yamaha intends to offer the sound generator chip, whose specifications are yet disclosed, to other mobile-phone handset makers.
KDDI expects its Mobile Number Portability system to alter the market share distribution in Japan's mobile-phone market. The current leader is NTT Docomo, with a 53 percent share, or 51.9 million subscribers. KDDI follows with 23.9 million subscriptions, or a 24 percent market share, and is betting on the introductions to boost its share to 30 million subscribers.