the same or better DB , we use a harsh enviroment roller sealed high speed NSK bearing not a basic off the shelf bearing ,so the noise level is much lower ....as with any quality bearing until broken in there is some roller noise , breakin normally takes 40 to 100 hours depending on your location and daily winds ....then it really quiets down
most wind generator noise is a result of the blades passing air flow , the better the blades the lower the noise
We used a carbon fiber composite for the blades which during the break in process and while under flow stress flex to achieve a perfect airflow
My blades are a carbon fiber composite
call me directly for any questions 409-457-2049
I will answer anything
ask me about the motor , the balance of the unit , the oring , the internal lube , the included controller , switch , fuse
i make a great unit ......tks Paddy

your windmill looks good, but what about the most important...... noise ?
how is it compered to the best once on the marked, on NOISE ?

Geir ove/Careka.