Bend - as anyone who recently moved here from Los Angeles can tell you - is a quiet little town.

Launch interactive graphic and audio

Full of sleepy streets lined with quaint craftsman homes, Bend resonates with the sounds of laughing children, tandem bicycles and wind sighing through ponderosas, right?

Now, put down the tourist brochure and take a listen to the actual Bend: Hammers thud on construction sites and traffic snarls around congestion. Horns honk, people shout, trains thunder, the river murmurs.

Bend is awash in all sorts of sounds, from vehicles to wildlife and the ordinary undercurrent of everyday business. Shut the car door, yell at the kids, jangle the keychain, shatter a glass. The soundtrack to our lives includes orchestras of train whistles and choirs of conversation.

How loud is that soundtrack?

Probably no louder - and likely a fair bit more quiet - than many other places, although the ratio of construction noise to other types of noise may be a bit higher in this high-growth area. For a look at just how loud Bend is, we turn to modern technology.

Measure mania

Last week, I armed myself with a Radio Shack sound level meter - a device that measures loudness - and set out to record Bend's sounds.

The meter, also known as a decibel meter, measures pressure generated by sound waves and translates that pressure via a complicated logarithmic formula into decibels.

Of course, I've just summed up in one sentence a complex scientific principle some people spend years studying. In reality, a decibel is the expression of a ratio - generally the ratio of sound pressure generated by a source to sound pressure at the threshold of human hearing. Because the human ear can detect such a wide range of sound intensities, we measure that intensity with a logarithmic, or exponential, scale, allowing enormous differences in value to be expressed in relatively small numbers, according to physicists at Georgia State University.

All this to say that the difference between 60 and 80 decibels is much larger than it appears - an 80-decibel vacuum cleaner is in fact 100 times louder than a 60-decibel normal conversation. A 90-decibel diesel engine is 1,000 times louder than that conversation.

(I should note that physicists do not use the term "loud" as a synonym for sound intensity, but newspaper reporters, lacking subtlety, do.)

Bend generates decibels all over the place. Traffic? A peak of 88 decibels at 20 feet away from the Parkway at 4:30 p.m. A crying 1-year-old at bedtime? A surprising high of 89 decibels at close range, which is loud enough, according to the National Institutes of Health, to cause hearing damage over a prolonged period.

The human ear, as it turns out, is an incredible sensitive instrument made up of many tiny bones, canals, membranes, chambers, hair cells and nerves working in concert to detect minute variations in air pressure. Abuse those mechanisms with too much, and you can damage the sensitive hair cells of the inner ear as well as the hearing nerve; ask any baby boomer with too many Rolling Stones concerts (110 decibels) under their belt.

Prolonged exposure to noises above 85 decibels can cause gradual hearing loss, according to the NIH. That's a condition more than 9 million Americans live with, and the number is likely to grow. Even young people - especially those who regularly use MP3 player ear buds - are at risk. Those ear buds routinely generate more than 90 decibels in the ear canal, and can produce 115-120 decibels.

Noises measuring 130 decibels and louder (jet engine at 328 feet) are painful. At 150 decibels (jet engine at 82 feet), your eardrums may rupture. The Occupational Safety and Health Administration recommends only two hours of exposure per day to sound measuring 100 decibels. At 115 decibels, OSHA recommends no more than 15 minutes.

Sounds of Bend

Bend isn't long on the kinds of noises that cause immediate hearing damage, but there are plenty of loud noises here, and plenty of soft ones.

The jackhammer used for road construction on Fourth Street last week generated a peak of 91 decibels from across the street. Similarly, the train rumbling by the Olney Avenue crossing - sans whistle - was a whopping 97 decibels from a nearby sidewalk.

The garbage truck's reverse-gear beeping measured 79 decibels. Children at play during Highland School's recess produced 80 decibels of noise.

But that's the thing about sounds: it's not all about the volume. I'd rather listen to 80 decibels of play any day than 79 decibels of warning beeps. One half of a 60-decibel cell phone conversation during dinner is 10 times as annoying as my 89-decibel baby crying.

Sound is subjective. Noises that bother some people are arias to others. Train whistles in the afternoon are quaint; in the middle of the night, they're sadistic.

Consider the baby's cry. Passengers will move to the opposite end of an airplane to avoid sitting next to a potentially crying baby. Yet that very noise is what keeps babies alive. Human ears are attuned to it so we can respond to feed a hungry, crying baby. Even the softest of baby's cries will wake a sleeping mother, so strong is the pull of that noise.

Or consider the noise of traffic. At 88 decibels on a busy street, it's one of the loudest noises we encounter on a daily basis. But how easy it is to tune it out.

The loudest things I recorded during my decibel meter experiments was not the train, not the the jackhammer, not even the sheet metal grinder (101 decibels). It was my own car stereo turned up to an uncomfortably loud volume, at least for me. At 107 decibels, it was loud enough to cause hearing damage; no more than 15 minutes of exposure would be recommended, the NIH says. Yet, dozens of cars pulling into Bend High School each day have stereos cranked that loud, their percussive bass beats shaking the air even half a block away.

The city of Bend has rules against such things. Its noise code prohibits radios, phonographs, etc., operated in a manner that disturbs the peace, quiet, comfort or repose of other persons. The code more specifically says if a cop can hear your stereo from 50 feet away, you're in trouble.

Of course, the city code also prohibits yelling, shouting, singing and even hooting on public streets between 10 p.m. and 7 a.m., or at any time when such activities would disturb people more than 30 feet away. I did not get a decibel reading of hooting, but presumably it's not louder than my ear-splitting stereo.

All in all, my favorite sound measurement was of the Des-chutes River dropping over a little riffle on the Bend River Trail at a soothing 66 decibels. Louder than an average conversation, but more pleasant than most, the river is perhaps Bend's defining sound. Sure, we have the hammers and trucks and trains and backhoes growling and banging and rumbling away all over town. But it's the river that makes Bend what it is. I, for one, suggest that gurgling, murmuring riffle is Bend's aural identity.