Amongst the range of headphones on display at Sennheiser's booth at IFA 2010 in Berlin recently were five new additions. The company has updated its audiophile 500 series and introduced a couple of mini headphones for mobile music enjoyment. While there's little change to the technical specs offered by The HD 518, HD 558 and HD 598 high-end cans, the company claims that the new PX 90 and PMX 90 phones are so lightweight and comfortable that you'll only know you're wearing them by the dynamic bass and lifelike sound image.

Sennheiser has made mostly cosmetic changes to its audiophile-grade 500 series headphones, so I won't dwell too much on these models. Sufficient to say that all retain the cleverly named Ergonomic Acoustic Refinement (EAR) technology, which is said to deliver a more natural acoustic sound by inclining the acoustic baffles to channel the audio directly into the ears. Fine soundscape detailing is helped along by neodymium magnets and Duofol diaphragms, and a gold plated audio jack helps ensure a solid connection to the audio source.

The HD 598 (successor to Sennheiser's HD 595) and HD 558 (the predecessor of which is the HD 555) both also benefit from an internal sound reflector said to optimize spatial sound characteristics. Gone is the gray and black coloring of the HD 595 in favor of the cream and wood grain of the HD 598. The changes to the color scheme of the HD 558 model are slight, now having less silver/gray and more black than its predecessor.

The silver/gray stripes on the cups of the entry-level HD515 model have given way to the "attractive anthracite finish" of the HD 518 but, like the other 500 series models listed here, the technical specs appear the same.

The only new feature Sennheiser has seen fit to bestow on the updated 500 series is a new detachable cable that unlocks with a twist.

Lightweight mobile audio performers

After a somewhat disappointing start, Sennheiser has also unveiled a couple of mini headphones that the company says are "so comfortable that you might even forget you are wearing them." The PX 90 has an over-the-head type design and the PMX 90 is the round-the-back-of-the-head type. Both supra aural models have been designed for music on the move and feature a 0.137-inch (3.5mm) jack for use with portable audio players, and include dynamic drivers that promise full-bodied sound with powerful bass. They share the same frequency response of between 20 and 20,000 Hz and the same 32 ohm impedance.

There's a slight difference in weight, the ergonomic wrap-around PMX 90's being the featherweight at 1.83 ounces (54g) compared to the PX 90's at 2.39 ounces (68g). Other than that, it's just a matter of personal taste as to which type are for you.

Sennheiser anticipates launching the new additions in the U.S. towards the end of September and, at the time of writing, is keeping tight-lipped about pricing.

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