For decades, Ray Choy has spent his weekends sitting in or standing beside cars that are louder than a major rock concert, a jackhammer, or a jet engine.

"I've sat in vehicles that are over 170 [decibels loud], and I still have pretty good hearing," he said ahead of a decibel drag racing event he organized in Calgary. "I have all my organs intact." 

Choy, who lives in Edmonton, organizes and serves as head judge for most decibel drag racing events in Canada. 

DB drag racing is a competition to create the loudest car stereo system. At events around the world, competitors, many of whom have ripped out their seats to make space for giant subwoofers, go toe-to-toe in knockout brackets. 

He said Alberta is home to about 15 to 20 serious competitors, who spend tens of thousands of dollars on modifications and travel to national and international events. 

"There are guys that are just hardcore," he said. "They spend every waking moment researching, figuring out the science behind how to get their vehicles louder."

Instead of playing music from their speakers, competitors typically play louder test tones, which make a deep humming sound, called a burp. 

The world record is listed as 180.6 decibels on the competition's official website, Termpro. That's about as loud as a rocket launch, according to Connect Hearing, a chain of national audiologist clinics.

"It can definitely take your breath away when you sit in some of the larger vehicles," Choy said.

Most serious competitors produce sound pressure levels of 150 to 155 decibels out of their speakers, still louder than Guinness World Record's loudest crowd roar at a sports stadium, which came at a Kansas City Chiefs game in 2014. 

To qualify for tournaments, participants must prove they can drive their vehicles a minimum distance. 

Ray said he's disqualified dozens of cars because they can barely move of their own power, from different events, but competitors are allowed to fix their cars before they're prevented from competing, and disqualification is rare at Canadian events. 

To produce the loudest burps, competitors sometimes spend more than $100,000 dollars on heavy modifications, said Ray's son Genevei Choy.