Re: laser levels.
For anyone interested I have an inexpensive solution. I own a Lazerpro (CL2060) which is a 16" (38 CM) aluminum level with a built-in dot or line laser light. Place it on a nearby surface (check for horizontal with the built in bubble level) adjusted for the height of your motor unit and use the laser line option to project the exact elevation for your arm mount.
I purchased the Lazerpro to facilitate speaker toe-in. That was several years ago but I'm certain it was less than $20.
For anyone interested I have an inexpensive solution. I own a Lazerpro (CL2060) which is a 16" (38 CM) aluminum level with a built-in dot or line laser light. Place it on a nearby surface (check for horizontal with the built in bubble level) adjusted for the height of your motor unit and use the laser line option to project the exact elevation for your arm mount.
I purchased the Lazerpro to facilitate speaker toe-in. That was several years ago but I'm certain it was less than $20.