Stepper Motor Resonance Questions

I am having some trouble with a resonance at relatively slow speeds causing
a lot of noise and occassionally missed steps. What are the parameters that
affect when this resonance occurs. I can set the control program up so that
it starts the motors at a speed above this resonance, but that doesn't help
when the calculated feedrate requires the motor to spin at the resonant
speed.

What can I do to aleviate this problem, or at least lessen it.

Thanks,

Daniel J. Statman, Statman Designs
www.statmandesigns.com