New York Dave Legeret silently fumed as the man seated beside him on the plane blasted techno music on his iPod at full volume.
"It was kind of rude," recalled Legeret, 38, a jewelry designer from Sandy Hook, Conn., who was forced to listen while flying from New York City to Disney World with his wife and 8-year-old son. "Listen to it at a level that just you can hear it and everyone else doesn't have to be subject to it."
Apple Inc.'s ubiquitous iPod is best known as an instrument of solitude - unless the user ignores standards of etiquette by invading the eardrums of fellow commuters, officemates or other innocent bystanders. Then it starts to get annoying. Especially when you're stuck in close proximity.
Amped to its highest volume, the iPod is not nearly as invasive as the classic loud cell phone conversation. But it can have its moments. Like when you're standing in an elevator at 9 a.m. and a co-worker cranks up Amy Winehouse's "Rehab." (Too early for that song.) Or when an ear-budded subway rider belts what sounds like a Whitney Houston tune with careless abandon, causing other riders to inch away or flee into another car altogether. (True story.)
"I've heard that problem quite a lot, people singing along," said Leander Kahney, managing editor of Wired magazine's Web site. "And, of course, my kids - when they have the iPod in, they shout. They don't realize with the headphones they're being too loud, so they'll conduct conversations without taking their ear buds out. And they're yelling."
That kind of behavior - an ignorance by the user of volume levels and surroundings - is more odious than the low buzz of the iPod, Kahney said.
"Did anyone ever complain about the noise coming from a Walkman or a CD player?" he said. "Unless you're in a quiet environment, you're really gonna have to strain to hear any kind of noise from somebody else's iPod."
Our world, he said, has become freakishly quiet. "It's not noise pollution - it's noise absence. And I find it almost more disturbing and upsetting than I did loud noise. It's sort of unnatural."
But in places and spaces where silence is golden - planes, trains and office cubicles, for example - even the slightest thump-thump-thump of bass can feel like a violation.
And then there's the impromptu karaoke problem. Kahney said a colleague at Wired, which covers technology and how it affects culture, has a bad habit of crooning to his playlist at work.
Any Celine Dion in the mix? "Oh no, he listens to these dreadful old hippie songs," he said. "You know, Creedence Clearwater Revival and the Allman Brothers."
All is forgiven after a friendly tap on the shoulder, Kahney said. A less confrontational approach may in order, though, when someone refuses to cooperate.
Anna Post, an etiquette instructor at The Emily Post Institute, said she'd heard a story about a woman who asked an iPod-using subway rider to turn down the volume, only to have her request ignored. So she used another tactic: singing along to the music.
"And, all of a sudden, boy, did that iPod get shut off," said Post, who stressed that "a little social shame can go a long way."
Like the cell phone, the iPod and other music players can foster a sense of apathy when the user is among strangers. It's easier to blow off social norms - and channel Justin Timberlake during rush hour - when you don't know who you're irritating.
"Sometimes people can feel a little anonymous in public," Post said. "Like, 'Oh. You know what? I didn't hear you. I didn't make eye contact with you. I can just ignore you and pretend like I'm not a bad person for doing this."'
Of course, many iPod noise polluters should be given the benefit of the doubt. They might be unaware that the volume is up so high. Or they may be hard of hearing (probably because they listen to such loud music).
If the noise is bothersome, Post said it's OK to speak up because most people would be hard pressed not to listen. If they don't, just "grin and bear it and let it go and just be the bigger person," she advised.
Or get an iPod of your own.
Legeret, the man stuck listening to techno on the plane ride to Florida, owns an iPod, as does his wife. They listen at respectable levels, and expect others to do the same.
"I'm really conscious of that," he said. "I'm the type of guy where if I'm in public, I'll try not to offend anybody if I can help it."