![]() ![]() If your ears are ringing after being subjected to a loud noise, the noise was too loud! Some studies say that continuous noise levels as low as 65 to 70 dB can interfere with normal thinking in some people! The pain threshold for loud noise is around 130 dB, with permanent hearing loss occurring at levels of 140 dB or higher. City traffic can produce sound in the 70 to 85 dB range, unless a trucker is using his “Jake Brake” (exhaust brake) to slow down his rig, which can push the dB levels considerably higher (one truck, even under normal driving conditions, typically makes as much noise as 10 passenger cars!). Normal conversation produces sound in the range of 45 to 60 decibels. For sounds over 100 dB, exposure should be limited to less than two hours per day. And the louder the noise, the shorter the acceptable duration of exposure per work day. The Occupational Safety and Health Act (OSHA) says protective ear equipment is required for continuous exposure to sounds of 85 dB or higher. Any prolonged noise over 85 dB is considered to be potentially dangerous. Noise induced hearing loss can occur with prolonged exposure to loud noise, or even short term exposure to loud sounds. Noise levels are important because too many decibels can damage our hearing. And if you’re stuck behind the wheel of a 20 year-old beater, noise is the least of your worries. On the other hand, if you’re driving a $65,000 Lexus, Mercedes or BMW 7-Series, quiet is synonymous with quality. If you’re driving a hot muscle car, you want it to sound powerful. The decibel level of the exhaust is important because of how we perceive it, and its effect on us psychologically and physically. ![]() This means that the intensity or energy imparted by the sound waves doubles for every 3 dB in the sound measurement. The decibel scale is an exponential scale rather than a linear scale. Sound levels are measured in units called decibels (dB). Louder sounds have more of an impact on our ears than softer or muffled sounds. Louder is the same as cranking up the volume on a stereo. SOUND INTENSITY Another factor that bears on how people perceive noise is the intensity of the sound. Low frequency tones also carry further distances than higher frequencies, and are harder to dampen inside the exhaust system. Such low frequency tones can easily penetrate the passenger compartment and create harmonics in the entire exhaust system, resulting in a droning, moaning or booming noise. At 2,200 rpm, which is a typical highway cruising speed, a V8 engine is spinning 26 times a second and is producing an frequency of 104 Hz. ![]() The high pitched buzz saw screech from a sport compact with a four cylinder engine and a straight-through muffler with a sewer pipe opening can be very annoying to other motorists.Ī V8 engine produces four exhaust pulses per revolution, a V6 or straight six produces three, and a four cylinder produces two. Those below 500 Hz or above 10,000 Hz are usually considered less annoying. According to studies that have been done on how people react to various sound frequencies, those between 2,000 and 8,000 Hz are typically considered to be the most annoying. A child with good hearing can hear higher frequencies up to 40,000 Hz. The average adult with good hearing can usually hear sound frequencies between 20 to 20,000 Hz. The greater the frequency, the higher the number of cycles per seconds (Hz) and the higher the perceived pitch of the sound. The frequency of these sound waves is measured in Hertz (Hz), which is the number of cycles that occur per second. The repetitive nature of the exhaust pulses from the engine create pressure waves that travel through the exhaust system and eventually exit out the tailpipe. Sound is nothing more than the compression and expansion of air waves. Unwanted sound from a vehicle’s exhaust system can be very irritating, especially if the sound frequency falls with certain ranges or is extremely loud. They say that introverts are less tolerant of noise than people who are extroverts. How people react to noise depends on a number of factors. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |