A variety of common noises, ranging from lawn mowers to routine traffic, are in violation of DeKalb’s noise regulations.

The DeKalb Municipal Code regulates noises under chapter 52, “Offenses against Public Peace, Safety, and Morals,” and section 35, “Noise Control Regulation.”

This means from 7 a.m. to 10 p.m. in residential areas, noise cannot exceed 60 decibels. Nothing more than 55 dB is allowed from 10 p.m. to 7 a.m.

But just exactly how loud is 55 or 60 dB?

I went on an adventure around DeKalb with an electrical engineering graduate student, Ravi Kishore Yenduri, to test common noises and their decibel levels.

The decibel measures the intensity of sound. Yenduri showed me the instrument he would be using – the sound pressure level meter.

With a small microphone at the top end, this equipment measures “instantaneous loudness,” which will tell a human exactly what they hear, Yenduri said.

Driving first to the intersection at Fourth Street and Lincoln Highway, we got out of the car and waited for the stoplight to turn green. Yenduri got the SPL meter ready and recorded the sound of traffic passing by us for five seconds. By doing this several times we could average the readings for a more accurate measurement.

The traffic measured 97 dB, well above the city’s limit.

Just as we were getting ready to move on to our next experiment site we saw the next batch of cars at the stoplight, which included a revving motorcycle. Yenduri looked at me and I looked at him and he got the SPL ready once again. We recorded 111 dB for the roaring bike.

Stopping at Sixth and Fisk streets, Yenduri took a recording of 61 dB for this quiet residential neighborhood. The only audible sounds were birds chirping.

I offered to climb over and punch his car horn and found the decibel level to be 97.

Other common noises Yenduri recorded included a lawn mower at the graveyard on Sycamore Road, near Clinton Rosette Middle School, at 85 dB. My voice, while talking in the car, measured 83 dB. Inside Yenduri’s car, with no one talking and the engine not running, the decibel level was 60 dB.

Heading back home, Yenduri and I drove past the NIU band beginning its practice between the Music Building and Wirtz Hall. Its practice measured 94 dB.

DeKalb also adheres to section 36, “Electronic Sound Systems,” in the Municipal Code.

“One can’t play sound reproductive systems that radiate past the dwelling on weekdays from 10 p.m. to 7 a.m. and weeknights from 12 p.m. to 7 a.m.,” said DeKalb City Clerk Donna Johnson.

Yenduri simulated a “loud party” in his apartment on Edgebrook Drive by turning up his rock music on his two-speaker stereo all the way. Inside the decibel level was 120 and outside it was between 105 and 110 dB.

Johnson addressed rumors the city issued permits for loud events.

“There seems to be a word floating around and no, we do not issue permits for loud parties,” Johnson said.

This is also the case for community events or fireworks. Only variance permits can be issued by the city manager for necessary road construction, she said.