@sasha - aside from flywhisk's very valid point

you know with any experiment,you must always have the same apparatus if you want to do the same thing twice - hence the vibrating driver is a prerequisite. Any substitute might affect the outcome of the experiment. Having said that. flywhisk is on to something

@flywhisk,haraaaammmmbeee!
The problem with equality is that we desire that it be with those that have more than us rather that those that have less