Can you share a picture?
I had quite a few voids in many prints until recently. With my problem, I went into RH and tweaked my setting per print. Most recently, I measured my current filament with a caliper (1,78mm), went into Repetier, and saw the stock setting was 3mm. This would mean that my extruder was not applying enough filament, leaving holes.
Also, calibrate your bed. Level it, make sure the hotend is a MetraCard/CTA card/business card away from the bed. There is a useful Solidoodle instruction on Vimeo.com. Just look up Solidoodle and scroll.
After I did all that, I've been getting quality prints.
As a recommendation, but a square of glass from a local shop and use it as a bed if you have not.
Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!