Major loud engine noise 2018 RT Limited Spyder Roadster comes from engine top end, cylinder heads, mechanical valve train operation including drive mechanisms, transmission system gearing and drive mechanism coupling to rear drive wheel.

Noise sound level measurements made at approximately two and a half to three feet from rider ear level to large instrument panel speaker grill work with open venting to engine compartment.

There appears to be serious acoustic coupling to major engine noise source and possibly some amplification due to “speaker effect” of large instrument/speaker panel area. More sophisticated sound measuring instrumentation would be required to prove this observation.

Large top outer panel right & left side engine compartment vents with wind deflectors facing rider also contribute to major engine/drive components sound level source.

Average range of human hearing between 400 and 8,000 Hz. Sound level measurements made with calibrated dB (A) scale instrument.

At speeds between 50-75 MPH in 6th gear sound levels range from 90 to 105 dB (A) with 110 dB (A) peaks. Higher frequency sound levels could also be a damaging factor but not measured. Normal lower gear operation and shifting noise levels could be even higher but this was not completely explored in this case.

Without good quality helmet including OSHA approved safety rated earplugs or equivalent hearing protection long-term exposure to sound levels of this magnitude will cause permanent damage to rider hearing.

Consideration for safety and rider comfort of future touring FT & RT Spyder model years.

Engineered acoustic sound isolation between engine compartment and rider instrument panel interface including sound absorbing material of at least ¼ inch thick applied to all inside surfaces of outer body panels surrounding engine compartment including lower rider outer body side panels.