Under control at Sarno

The noise limit of 108 dB, as with any new rule, is much talked about in the small world of karting, which is after all very conservative. Yet the willingness shown by the CIK to reduce noise is undoubtedly a very good thing for our sport. After much criticism in the paddock on the validity of the measures, we looked more closely at what the real procedure is. Apparently, this is serious!

CIK has long worked with two Italian experts in acoustics, Studiogamma and Eco Progetti, who are frequently involved in motorsport, for example at Monza. In this case, Apex Timing uses its expertise to combine the data for the competitors and publish figures on the results sheets.

The measurement itself is performed by four high quality microphones hanging 2.5 m above the ground, near the timing line. The microphone is designed to record only the sound of the karts. The pickups are calibrated each morning with a certified calibration device. The sample is greater than 50 000 Hz and the data are then measured according to a strict standard (IEC 651, A scale or equivalent).

The processing of the data receives special attention, with complex automated computer procedures using specific programs. It is firstly to ensure that the measure is valid, that is to say, it involves only one kart at a time. A minimum distance of 0.25s is required between the karts for the measure to be valid. Any possible echo is eliminated. The various measures are then associated with the driver concerned and averaged by eliminating extreme values, then rounded to the nearest half decibel.

The level assigned to each kart during a session is then added to the corresponding results sheet. Penalties for going over the maximum allowed of 108 db are ultimately managed by the stewards. The regulation is: 3 second penalty for under 1 dB in excess, 6 seconds for between 1 and 2dB, 9 seconds for between 2 and 3 dB. Exclusion may be considered beyond that or in case of recurrence.

However, any figure is only valid where it is measured, it is necessary to adapt, and even be noisier elsewhere. On the other hand, drivers who are too quiet will likely seek to increase the engine power to go closer to the limit. It is the spirit of the competition…

Info Kartcom with Kartlink / © Photo KSP