User manual SENNHEISER HDC 450

[. . . ] Noise also affects the vegetative nervous system, and can permanently damage the hearing. The sources of noise are many and diverse and, all too often, cannot simply be turned off. [. . . ] The sources of noise are many and diverse and, all too often, cannot simply be turned off. So, in noisy places, personal protection is the only remedy. With the NoiseGardTM system, Sennheiser have come up with an effective solution. These instructions explain its functioning principle and operation. Sound level of noise sources 140 dB 130 dB 120 dB 110 dB Jet engine (at a distance of 82 ft) Aircraft engine Pneumatic drill Forging hammer, concrete works Metal die-casting machine Metal works Tractor Office Conversation Environmental noise Living room Library Bedroom Forest, no wind A noise reduction of 10 dB is generally perceived as a halving of the noise level. If the noise is reduced by a further 10 dB, this is perceived as a 75% noise reduction, and so on. the NoiseGardTM compensation electronics in the headphone requires its own power supply. This is provided by the power supply unit which is fixed to the cable. Noise compensation with NoiseGardTM Inserting the batteries in the power supply unit Reduction of the subjectively perceived noise level with Noisgard Technical Data Acoustic principle Frequency range Impedance Total harmonic distortion Active compensation Headband pressure Weight without cable Cable Power supply Operating time Display Delivery includes 110 g one-side only, total length 2 m with 3. NoiseGardTM is not a noise protection system for medical purposes!Listening to music via headphones tempts into listening to louder music than loudspeakers would. A high volume that affects your ears for a longer period can cause lasting hearing defects. [. . . ] Listening to music via headphones tempts into listening to louder music than loudspeakers would. A high volume that affects your ears for a longer period can cause lasting hearing defects. [. . . ]