I just received my RO 150 and Deltex 93. I'm a bit surprised at the noise level of these. They sound somewhat more like a drill running, than the sanders I'm use to using (Makita and Hitachi 5" ROS sanders). Is this normal?
I second Lou's comments. Both the Rotex and Deltex sanders are fairly loud. The RO 150 is especially loud, makes a kind of grinding sound. Nothing to worry about.
Call me nutty, but I actually like the sound of these sanders! But if I'm working for extended periods, as I usually am with these, I wear hearing protection. I describe the noise level in my review of the Rotex sanders, which you can find by clicking here.
For your information (in case you are considering expanding your Festool arsenal) the RAS 115 makes a similar grinding sound. I like that sound too! I mention this in my review, which you can find by clicking here.