Old Lyme, Conn. - Sennheiser has rolled out enhanced versions of its Travel series headsets, adding compatibility with the Apt-X codec, which provides enhanced fidelity and clarity to music playback and phone calls on computers and portable devices.

The MM 400-X and MM 450-X are on-ear style headsets while the MM 500-X and MM 550-X are over-the-ear headphones models.

The top-of-line MM 450-X and MM 550-X add proprietary NoiseGard 2.0 active noise-cancellation and TalkThrough technology enabling users to communicate with others nearby without removing the headset.

Additionally, the MM 550-X adds SRS Wow HD audio processing.

The headsets are compatible with any Bluetooth-enabled device that supports A2DP and HFP/HSP profiles.

Talk time is said to be up to 20 hours on a full charge, with listening time up to 10 hours without NoiseGard, up to eight with.

The MM 400-X, MM 450-X, MM 500-X and MM 550-X are available now at street prices of $270, $450, $330 and $500, respectively.

A USB dongle is also available for consumers using devices without Apt-X capability, to add Aapt-X transmission to any device-based music system.