4 vs 2 noise level , you’d have to compare two engines side by side, with the same power rating and the same muffler for the same application. I have no way to do that. But among my landscaping-work small engines, the 4-stroke lawnmower is the loudest.
There’s a cell phone app for that: NIOSH SLM. Load the app, start it, and lay your phone down on a table about 20 feet away from the motors. Run the 2-stroke and record the sound level. Then run the 4-stroke and record the level. Easy-peasy.
Easy peasy to compare the noise levels, but not so easy to secure two identical powered and muffled engines.
No two stroke and four stroke engines will be ‘identically powered and muffled’. They don’t exist.
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You can make it as hard as you want to George. I was thinking more like get two leaf blowers that provide the same air flow and run the noise test.
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I think Consumer Reports performed those evaluations 25 years ago when noise regulations were created in some California cities.
My neighbor’s gardener has one of those old, outlawed leaf blowers, sounds like an airliner taking off.
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If you clap your hands twice as fast, is it twice as loud?
DB level will be the same, but total volume will increase.
Volume stays the same but frequency (pitch) increases.
Agreed. However, 2-stroke engines have higher cylinder pressure than a 4-stroke (extreme exceptions of course) and the exhaust port is opened much earlier on the down stroke than a 4-cycle exhaust valve opens on the power stroke. Therefore, a 2-stroke has higher cylinder pressure when the exhaust opens. But, a 2-cycle also has a smaller exhaust port/cylinder so… I agree with you that a 2-stroke will generally “sound” louder due to the increased frequency.