I understand what you are asking, you want a before and after comparison. When you call to talk think I can give you the answers that you are looking for...

Thanks, Tony

 

For those interested Ark does have DB measurements like I was describing. Here's a video of them showing stock vs their GRIP exhaust in terms of DBs:

Infiniti G37 Coupe Factory Stock OEM Exhaust Vs. ARK GRIP Exhaust Sound Clip - YouTube

 

Ehhh still wouldn't go for it.

 

Thank you for the call yesterday! I am hopeful that I was able to answer your questions. If you have further questions or would like to place an order, please do not hesitate to call me directly.

Thank you, Tony

 

Her's an excerpt from the CA DMV:

CCR 1036 Passenger Cars and Light Trucks and Buses

Exhaust systems for motor vehicles, other than motorcycles, gross vehicle weight rating of less than 6,000 LB (2,722 kg) shall comply with the specified noise limits when tested in accordance with the following specifications:

(a) Measuring Site. The vehicle under test shall be positioned either on outdoor pavement or on a shop floor ( but not over a hoist or pit) in a location where the exhaust outlets are near an open shop door. No sound-reflecting surface other than the pavement and the vehicle being measured shall be within 10 ft (3.0m) of any part of the vehicle.

The testing is done in an environment in which there is minimal sound contamination. Please note that there is nothing stating highways or other public roads as being an exception to this criterion.

(b) Microphone Location. The microphone for the sound level meter shall be at the same height as the center of the exhaust outlet. The microphone shall be no closer to the pavement than 8 in. (203mm) when the exhaust outlet is lower than this height. The microphone shall be positioned with its longitudinal axis parallel to the ground, 20 inches plus or minus 1 inch (508mm plus or minus 24mm) from the nearest edge of the exhaust outlet, and 45 degrees plus or minus 10 degrees from the axis of the outlet. For exhaust outlets located under the vehicle body, the microphone shall be located at the specified angle and at least 8 in., (203mm) from the nearest part of the vehicle. For exhaust outlets that make an angle of 45 degree or less with the longitudinal axis of the vehicle, the microphone shall be outboard of the exhaust axis. For exhaust outlet angles of more than 45 degrees, the microphone shall be on the side of the exhaust axis to the rear of the vehicle.

This denotes where the sound measuring device is relatively close to the exhaust outlet. Notice that it does not make any references to provisions for sound level testing done from distances greater than 21 inches. <

(c) Engine Operation. The engine shall be at a normal running temperature with the transmission in neutral. System sound level measurements conducted for certification by exhaust manufacturers shall be made at an average steady-state engine speed of three-quarters of maximum rpm. Sound level measurements conducted by licensed muffler certification stations shall be made at an average steady-state engine speed of 3,000 rpm for vehicles manufactured before 1972 for which the station does not have a maximum rpm data.

Please notice that the engine is supposed to be running and the law has no provisions for parked vehicles. Note that the certification can be done by the manufacturer of the exhaust system. There is no requirement that the manufacturer sound test each individual vehicle. Re: "licensed muffler certification stations," the letter from the California Highway Patrol file Number 60.A9190.A9181.062.9610186 states in the third paragraph that these facilities were canceled in 1978 due to budgetary cut-backs.

(d) Exhaust Sound Level Measurement. The recorded exhaust system sound level of a stationary vehicle shall be the highest reading obtained during the test, disregarding unrelated peaks due to extraneous ambient noise. When there is more than one exhaust outlet, the reported sound level shall be for the loudest outlet. When there are two or more exhaust outlets separated by less than 12 in. (305mm), measurements shall be made on the outlet closest to the side or rear of the vehicle. (Figure 4). The sound level for the motor vehicles with the manufacturers' gross vehicle ratings of less than 6,000 LB (2,722 kg) except motorcycles, shall not exceed the following limit:

The statement stating extraneous ambient noise refers to noise coming from places other than the exhaust. For this reason, testing cannot be done in a sound-contaminated environment. It would be logical that a roadside or a highway would be a sound-contaminated environment.

(1) Sound Level Limit. The exhaust noise shall not exceed 95 dB(A).

 

Thank you for posting this! It shows three things by you doing it.

1) I need to look harder and in the right places and I will find the correct information!

2) Clearly the CHP officers I talked to were either to busy to give me the right direction or did not know themselves!

3) Now we have a clear cut way on how to preform a DB test...

Thanks, Tony