My BR400 does ~170mph, ~500cfm, ~73db. It works well on most things. I wish it had a little more power for those big piles, even moreso if they are wet. It moves them but I have to take it in smaller chunks.

You need noise to make power. Get a good set of ear protection.

Unfortunately, the answer is yes. Engine rpm is limited to reduce noise and the machine loses power.

Yup, power and noise tend to go together. Some exceptions exist, but then it's just a relative reduction.

I run four blowers around the house: an old Toro gas blower (weak, but an old friend), Stihl BG85 (powerful handheld!), Stihl BR420 (~BR400, and I echo masiman's comments), and a Parker walk-behind (8hp Honda GX). Each blower has its own purpose, though the backpack does a pretty good job on most things. I would not bother with a backpack blower unless you were going to get to the BR420 level or better. Those little mini-backpack blowers would barely move grass clippings off the sidewalk, much less mountains of leaves!

If noise is your main concern, Stihl's 4-mix engines (BR500, 500, 600) are very nice and quiet, and the BR600 in particular is a powerhouse.

Thanks for the replies. You guy think Husky 150Bt 50cc, 495cfm with tube, 180mph with tube strong enough? The spec should be close to Stihl BR420 but noise spec 71dB vs 73dB which is quite segnificant.