It is all in the muffler
And the muffler is usually part of the mower, not the engine
On mowers that come with mufflers fitted B & S usually give the option of a std one & a"low-tone" one which is a little quieter
Engine speeds also make a big difference ,
Hondas typically spin at 3200 rpm down here and sound very quiet when next to a B & S running at 3600 rpm
The "too quiet for the USA Victa Vortex" spun at 3100 rpm and can not be hear from 20 foot away .
