Mr Camp said the system provided a guide for those looking for the right amount of background noise.
"If you're going out for a few beers with a couple of mates and want a loud, boisterous venue, then your one-star or two-star venue is probably just about right.
"If you're going out for a relaxed dinner to talk with friends, then you probably want a four-star or five-star venue."
It was often eateries with certain features that were loudest, he said.
These included the trend for industrial-styled interiors with brick walls, concrete floors and hardwood furnishings; where music was playing loudly; or where roadside dining coincided with heavy traffic.
The Herald visited five Auckland premises this week. Decibel readings showed roadside Cafe on Kohi - visited in the morning - to be the loudest, with traffic noise and other customers making it hard to hear dining companions.
A reading of 85dBA was the standard for a crowded restaurant, but Mr Camp said 75dBA was the level a comfortable conversation could be held.
Cafe on Kohi read at a maximum of 83.4dBA, while a busy lunch time at Circus Circus in Mt Eden read at a maximum of 77.8 and a quiet mid-afternoon Shaky Isles Britomart read at a maximum of 68.4dBA.
Banque in Remuera had the lowest rating on Mr Camp's index and despite being nearly empty when the Herald visited, it was surprising how sound travelled in the establishment.
Auckland eatery Shaky Isles has three city locations and each sports industrial-styled decor. General manager Rob Rivers said noise level was constantly managed and tables were spaced out to reduce sound. "Mainly it is music levels that determine how loudly people speak so we try to keep music to the perfect level."
Quiet enough for a chat
Noisy restaurants and coffee shops are enough to make Aucklander Tim Signal go somewhere else.
"I prefer a quiet night out sitting with friends talking. If everything gets to a level where it's too hard to converse with people ... I avoid it if I can," he said.
The 35-year-old said it was important for the atmosphere of an establishment to be accommodating and tolerable.
"If the atmosphere is wrong it doesn't matter how good the food is or how nice the place is."
Hustle and bustle were part and parcel of some eateries, he said, but needed to be controllable.