* Resonance: This is the most likely cause. Resonance occurs when an object vibrates at its natural frequency. In the case of your car, the engine, exhaust system, or other components may be vibrating at a frequency that is amplified at 60-65 mph. This can cause the engine to sound louder. As you accelerate past 70 mph, the frequency of the vibration may change, causing the noise to quiet down.
* Wind noise: Wind noise can also increase as you drive faster. This is because the faster you drive, the more air flows over your car. This can create a whistling or roaring sound. The wind noise may be louder at 60-65 mph because this is the speed at which the airflow over your car is the most turbulent.
* Mechanical problems: In some cases, a loud engine at 60-65 mph could be a sign of a mechanical problem. For example, a loose or damaged engine mount could cause the engine to vibrate excessively. A worn or damaged exhaust system could also cause the engine to sound louder. If you are concerned about the noise your engine is making, it is best to have it checked out by a qualified mechanic.
Here are some additional tips for reducing engine noise:
* Keep your engine well-maintained. This includes changing the oil regularly, replacing worn spark plugs and wires, and cleaning the air filter.
* Use high-quality fuel. Lower-quality fuel can contain impurities that can cause the engine to run rough and produce more noise.
* Drive at a moderate speed. Driving faster than necessary can increase wind noise and engine noise.
* Install soundproofing material. Soundproofing material can help to absorb engine noise and make your car quieter.
