Looking at your posted video everything seems to be ok to me...
The "sound" is the regular noise of scanners when driven close to their limits (usually because too many points to project or/and too large size of figure projected)
If you reduce images size or projection angle, the "sound" will surely decrease.
Remember that your scanners can run at 30K
ONLY when setting small projection angle (most times from 4 to 6/8 degrees).
To know how much exactly is your output projection angle (this example =
8 degrees), do this easy way:
- place your projector 1 meter far from a wall.
- create a simple square figure (full size on grid of your software) and project it.
- measure dimensions of the square projected on the wall: each side of square must to be 14 centimetres.
Example for angle = 8 degrees (as just said above)
distance x tangent of angle = width of figure on the wall
100cm x 0.1405 = 14.05 cm
For more info, take a look here
http://www.pangolin.com/userhelp/scanangles.htm