Cairo Egypt 85 Decibals Average Noise

This is not like London or New York, or even Tehran, another car-clogged Middle Eastern capital. It is literally like living day in and day out with a lawn mower running next to your head, according to scientists with the National Research Center. They spent five years studying noise levels across the city and concluded in a report issued this year that the average noise from 7 a.m. to 10 p.m. is 85 decibels, a bit louder than a freight train 15 feet away, said Mustafa el Sayyid, an engineer who helped carry out the study.

But that 85 decibels, while “clearly unacceptable,” is only the average across the day and across the city. At other locations, it is far worse, he said. In Tahrir Square, or Ramsis Square, or the road leading to the pyramids, the noise often reaches 95 decibels, he said, which is only slightly quieter than standing next to a jackhammer.

In a nation where about 40 percent of the population survives on about $2 a day, people understand the struggle to feed a family. In Rhode al Farag, men worked on cars in the street, butchered meat in the street, blasted radios and turned up television sets. Like shellshocked war veterans, residents sat out on the street, sipping tea, oblivious to the cacophony.

Hat tip to Randall Parker:
parapundit.com/archives/005161.html

nytimes.com/2008/04/14/world/middleeast/14cairo.html?th&emc=th

85 dB means nothing. It is a referenced value. We don’t measure in dB. We measure in Watts (dBW) or Milliwatts (dBm). What is that value and then we’ll have something empirical.

If these people are scientists they know that.

dB’s are log rhythmic. Every 3 dB doubles (or halves, depending in which direction you go) the measured. Every 10th dB is a factor.

1 watt = +30 dBm = 0 dBW
2 watts = 33 dBm = 3 dBW
10 watts = +40 dBm = +10dBW

See?

Now if the story means to say it was measured at +85 dBm that’s 316,227,766 milliwatts. Now if it’s +85 dBW that would be 316,227,766 Watts !!! - Holy Smokes, Batman! There aint no way anyone is living anywhere near that.

Now with regard to sound it is measured in terms of loudness (intensity) and pitch (frequency). The unit of measurement for intensity is Decibel Sound Pressure Level (dBSPL). For pitch the unit of measurement is Hertz (Hz). A person with normal hearing can typically hear sounds up to 120 dBSPL. Above 120 dBSPL sounds become very uncomfortable and can be damaging. The same person can typically hear and tolerate sounds within the pitch range of 20 to 20 KHz. However, during a hearing test only the range from 125 to 8 KHz is measured. The speech sounds are included in this range.

So if the article is saying it is +85 dBSPL - well that’s somewhat loud but not deafening. I would venture to say that 4 children running around in the kitchen produces greater than +85 dBSPL, or at least they do at Erik’s house :stuck_out_tongue:

tosses flag

You also have to remember the Arab culture. It’s all man for himself. They drive like a maniac and blow their horn like they ain’t never see a horn in their life. They all seem like they are always in a hurry. Most Americans afraid to drive in the Middle East. For me, I love it.

Hi B,

I didn’t know there were so many values to a decibel. When we were installing a machine at a customer, the target was 70 decibels in their operating environment. I know the competitor we were replacing was higher than that, as the operators required ear protection.

Was that unit of measurement most probably dBSPL? If so, my guess is that is the same unit they are referring to in the article. I’ve never heard anyone refer to noise in anything other than “decibels.” :shrug:

Yeah “decibels” (a tenth of a Bell, a unit invented by Alexander Graham himself) is a buzz word and a taken-for-granted term as well.

My speakers have a gain of 45 dB!!! Well Golly Gee Wilikers, Batman so effing what? What’s the input range and the bandwidth? If you have an input range of only 1 milliwatt your maximum output across a given band without cascading to complete saturation and distortion is a whopping 20 - 25 watts - Ohhhhhhhhhhh, your Dodge Neon will be rockin’ now won’t it? :smiley:

I think that when any industry that uses dBx people get sloppy and just refer to any measured value in dB thinking the people they are talking to automatically put in the measured, which is true if they are talking to an intended audience. It’s just a one of my pet peeves as a dorky Satellite guy. :nerd:

Wait a minute now! :hmmm: If you are a “Satellite guy,” shouldn’t your profile’s location list “in orbit around the Earth” rather than just “Earth?” :wink:

hehehe. Back in my Army days I was known as “Satellite Maaaaaaaaaan.”

In flight Satellite Repair with a smile. :smiley:

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