I think you are blowing this thing with the blower sound ratings way out of proportion. The echo has a 65db rating the Stihl a 73 db and you are trying to tell me you can hear a 8db difference, I really don't think so. As I said in the previous post the sound difference you will hear is the difference between the sound of a 4 stoke and a 2 stoke engine only and the 4 stoke is always quieter than a 2 stoke or at least has a lower tone quality which is less offensive to the ear. The or a 2 stoke will be louder than the 4 stroke with the same db, it's the nature of the beast. I can set my BR 550 and BR 380 next to each other running wide open and guess what the 380 was loudest of the two, we tested it this morning and both are running the same 73 db. Read your own article below, it's all in the perception.
While Stihl has developed electric models, they have put most of their efforts into a hybrid dubbed the ?-cycle mix, which features a 4-stroke engine that burns a gas/oil mix. Stihl has reduced the noise level of their equipment in recent years, paying attention to the difference between the technical measurement of noise and the human perception of noise.
展ith the 4-cycle mix hybrid, the equipment has a more pleasant sound, not the high-pitched whine traditionally associated with 2-cycle equipment, so it is often perceived as being quieter, Hanks says. He adds there is not an industry standard for measuring sound for trimmers and chain saws, etc., but blowers are measured per ANSI B175.2. (American National Standards Institute).
