At the ripe age of 28, Jon Zimmer is sort of an old fogy. That is, he is obsessive about the sound quality of his music.

A onetime audio engineer who now works as a consultant for Stereo Exchange, an upscale audio store in Manhattan, Mr. Zimmer lights up when talking about high fidelity and $10,000 loudspeakers.

But iPods and compressed computer files - the most popular vehicles for audio today - are “sucking the life out of music,” he says.

The last decade has brought an explosion in dazzling technological advances - including enhancements in surround sound, high-definition television and 3-D - that have transformed the fan’s experience. There are improvements in the quality of media everywhere - except in music.

Indeed, in many ways, the quality of what people hear has taken a step back. To many expert ears, compressed music files produce a crackly, tinnier and thinner sound than music on CDs and certainly on vinyl.

In one way, the music business has been the victim of its own technological success: the ease of loading songs onto a computer or an iPod has meant that a generation of fans has happily traded fidelity for portability and convenience. This is the obstacle the industry faces in any effort to create higher-quality - and more expensive - ways of listening to music.

“If people are interested in getting a better sound, there are many ways to do it,” Mr. Zimmer said. “But many people don’t even know that they might be interested.”

Take Thomas Pinales, a 22-yearold from Spanish Harlem and a fan of some of today’s most popular artists, including Lady Gaga, Jay-Z and Lil Wayne. He listens to his music stored on his Apple iPod through a pair of earbuds, and while he wouldn’t mind upgrading, he is not convinced that it would be worth the cost.

“My ears aren’t fine tuned,” he said. “I don’t know if I could really tell the difference.”

The change in sound quality is as much cultural as technological. For decades, starting around the 1950s, a high-end stereo system was something to show off, much like a new flat-screen TV today.

Nowadays, music is often carried from place to place, played in the background while the consumer does something else - exercising, commuting or cooking dinner.

In fact, among younger listeners, lower-quality sound might actually be preferred. Jonathan Berger, a professor of music at Stanford University, said he had conducted an informal study among his students and found that, over roughly seven years, an increasing number preferred the sound of files with less data over the high-fidelity recordings.

“I think our human ears are fickle. What’s considered good or bad sound changes over time,” Mr. Berger said. “Abnormality can become a feature.”