A recent noise study objectively determined that one of the occasional auto racing events in the parking lot of Hoffman Estates' Sears Centre Arena wasn't dangerous to the hearing of anyone there or of neighbors living just across the Jane Addams Memorial Tollway.
But how annoying the noise may be -- and to how many -- is the subjective question officials continue to weigh as they consider the future of such events that generate a total of $50,000 to $70,000 for the village-owned venue each year.
"There's not enough evidence in what we collected that there's a definite annoyance," said Tom Thunder, principal of Acoustic Associates in Pingree Grove.
Virtually all the complaints village officials have received have come from resident John Manfredi, who lives at the edge of a cul-de-sac directly across the tollway from the Sears Centre's parking lot.
Manfredi was the only resident who attended Monday's meeting of the village's finance committee, where the results of Thunder's study of a July 21 racing event was discussed.
He said that whatever scientific studies say about levels of acceptable noise, only he and his neighbors have to endure it for an entire day or weekend at a time.
While one such event earlier this month was acceptable to him, Manfredi said the noisiest of all at the Sears Centre is one called "The Ultimate Driving Experience."
Village officials said the next one of these is scheduled for Oct. 10 and 11 and that they were interested in what test results would say about it.
Short of danger levels, Thunder said, the most his tests can determine about acceptability is calculating the amount of noise that would disturb a reasonable person.
Levels at the July 21 event were measured at between 60 and 90 decibels throughout the day. While 60 decibels is about the level of a conversation, 90 decibels is about as loud as a lawn mower.
For every increase of 10 decibels in a measurement, the level of noise doubles. But even 90 decibels is both safe for human hearing and legal.
Ben Gibbs, general manager of the Sears Centre, said these racing events have been run for six years already.
"We're trying to run a business and keep everyone happy," Gibbs said.