An ear canal pressurization device optimized for aural acoustic immittance testing is disclosed. Changes in volume of a first flexible chamber, due to motor movement, produce changes in ear canal pressure based on Boyles law. A vent may be opened to allow ear canal pressure to gently equalize to ambient air pressure or to generate ear canal pressure sweeps free of pressure baseline offset. The vent may be closed to set a static ear canal pressure or to generate ear canal pressure sweeps with an incidental baseline offset. The vent may be controlled to generate ear canal pressure sweeps with an intended baseline offset. The device produces ear canal pressure proportional to drive voltage, so any desired pressure versus time function can be generated by applying a coil driving voltage with the appropriate amplitude versus time function.