We live at the bottom of an ocean of air that constantly exerts a pressure on us. We experience the sensation of sound when our eardrums are stimulated by sound waves in the air around us. Sound waves are vibrations created when an objectsuch as a car engine, a loudspeaker, our vocal cords, or a tuning forkcauses a disturbance or change in the air pressure around it. Acoustic experts measure sound waves in a variety of ways, but sound waves are commonly described in terms of frequency and amplitude. Most of the sounds we hear are a complex mix of different and overlapping frequencies and amplitudes.
Each sound wave increases and decreases the background air pressure many times per second. The number of wave cycles per second is the sound waves frequency or pitch, which is typically measured in Hertz (Hz). Each Hz represents one wave cycle per second. If our ears are working perfectly, we can hear frequencies from about 20 Hz (for example, the largest organ pipe) to 20,000 Hz (for example, some dog whistles). As we move away from the source of a sound, the pressure drops approximately in proportion to the distance. As the distance from the sound source doubles in length, the sound pressure level is reduced by half.
The height and depth of sound waves is referred to as amplitude or loudness. As the amplitude increases, the volume increases. Our ears can detect sound over a very wide range of amplitudes, which are often measured and described in terms of decibels (dB). The softest sound humans can hear is approximately 0 dB.
Sound waves collected by the Pinna (outer ear) are funneled down the ear canal and set the ear drum in corresponding motion. The malleus, incus and stapes (also known as the hammer, anvil, and stirrup) transfer these vibrations to the spiral shaped structure called the cochlea. The cochlea is a fluid filled chamber lined with minute hair cells that are sensitive to different frequencies. When exposed to the vibrations caused by various sound waves, the hair cells send nerve impulses to the brain and the brain interprets those nerve impulses as the variety of sounds we hear.
Exposure to loud sounds may cause temporary or permanent damage to the hair cells in our ears and, accordingly, damage our hearing because the hair cells cannot transmit sound to our brain. A single, very loud soundsuch as a gunshot or an explosioncould cause immediate hearing loss. Prolonged exposure to other loud sounds over an extended period of time could also cause hearing loss.
Given the potential risk of temporary or permanent hearing loss associated with exposure to loud sounds, it is wise to be conservative and use common sense in your listening habits. For example, you should use earplugs when operating noisy machinery or firearms. Keep your distance from heavy construction equipment or jet engines. When listening to music or other audio (with or without a headset or headphones), keep the volume at moderate levels and limit the amount of time you listen.
Although there is no single volume setting that is appropriate for everyone, you should always use your headset or headphones with the volume set at moderate levels and avoid prolonged exposure to high volume sound levels. The louder the volume, the less time is required before your hearing could be affected. You may experience different sound levels when using your headset or headphones with different devices. The device you use and its settings affect the level of sound you hear. If you experience hearing discomfort, you should stop listening to the device through your headset or headphones. To protect your hearing, some hearing experts suggest that you:
Directive 2002/96/EC on waste electrical and electronic equipment (WEEE Directive) seeks to reduce the environmental impacts of WEEE throughout all stages of the equipment's lifecycle, particularly at the end-of-life stage, by encouraging the end-of-life management of the product, eco-design, life cycle thinking and extended producer responsibility.
To comply with the WEEE Directive Plantronics will, where possible, register with the national registries and as well as with collective scheme operators.
Plantronics will inform consumers on the sound disposal of the WEEE and inform the treatment and recycling operators on reuse and treatment of each type of new EEE put on the market.
Plantronics will mark all its products with the symbol of a crossed-out wheelie bin as shown below.
Products labelled with the symbol of a crossed-out wheelie bin as shown below are electrical and electronic equipment (EEE). The crossed-out wheelie bin denotes that waste electrical and electronic equipment and batteries must not be disposed with the remainder of non-separated household waste, but should instead be collected separately as prescribed by the local laws and regulations.
Electrical and electronic equipment (EEE) and batteries may contain materials, components and substances which can be dangerous to the environment and harmful to human health if not disposed correctly.
Waste electrical and electronic equipment and batteries can be delivered free of charge by any private person to recycling stations or to other collection sites, or it can be collected directly from the households. For more detailed information, please refer to your local municipality, your household waste disposal service, or the shop where you purchased this product.
As a consumer, you should not dispose of electrical and electronic equipment and batteries together with your household waste. In this way, the environmental impact associated with disposal of electrical and electronic equipment and batteries is reduced and there will be more opportunity for reusing, recycling and recovering electrical and electronic equipment waste.