<img src="http://www.avforums.com/news/images/20050907122857.jpg" align="right">Headphone guru Sennheiser has just launched a new, iPod-friendly gloss-white version of its renowned PXC 250 headphones.</p><P>Costing around £100, the foldable white PXC 250Ws also offers Sennheisers NoiseGard noise reduction system, used by BA & Lufthansa Pilots for cutting out the effects of external sound during headphone use. </p><P><b>Key features of the PCX 250W:</b><br>* compact fold-flat design<br>* weigh just 65gms<br>* advanced NoiseGard active electronic noise reduction<br>* new closed design for extra noise reduction, giving around a 70% reduction in ambient noise overall<br>* dynamic, clear sound<br>* reduce risk of hearing damage<br>* work with iPods, portable CD, airline systems and more</p><P><b>The NoiseGard effect</b><br>* Continuous engine / motion noise is dramatically reduced<br>* Vocal and musical intelligibility is increased <br>* All listening can be carried out at lower levels, reducing the real risk of hearing damage from listening at high volumes,<br>* Stress is reduced due to the reduction in overall noise levels.<br>* Vital warning & emergency signals remain clearly audible (unlike ear defenders or earplug phones)</p><P>NoiseGard works like this: A tiny microphone inside each earpiece 'listens' to ambient noise. This noise is then reversed in phase and fed back into the earpieces. The out of phase anti-noise cancels the real noise, leaving the desired signal. Sennheiser claims that continuous noise between 400 and 1000 Hz is reduced by approx -10dB.