Criteria for selecting drivers for current-drive

In principle, no special drivers are needed.

Current-drive gives

• Lower distortion
• Wider usable bandwidth of drivers
• Extra dynamics and no power compression

And to exploit this even more, select drivers for

• Low distortion
  • Low distortion design
  • Non-conducting voice coil formers
  • No ferro fluids
• Low frequency output
  • Big displacement (Vd)
    • Big diaphragm area (Sd)
    • Big excursion limits (Xmax)
      • Big diaphragm area (Sd) is more important, bigger excursion limits (Xmax) often means that the cone is more heavy, because the (moving) coil is bigger
• High frequency output
  • Consistent dispersion
  • Smallest diameter: one single round driver per band
  • Smooth response, no or small peaks (for correction)
• High efficiency
  • Low resonance frequency (fs)
  • Low moving mass (Mms)
  • Big diaphragm area (Sd)
  • Low nominal impedance

Scan-Speak has several lines.The Discovery line, Scan-Speak’s budget line, has the most and best options (Discovery).

For active currents-drive systems the Q of the driver is not critical. But with a very high Q, the resonance frequency needs to be stable for an accurate damping of the resonance. With a current-drive system the impedance curve is easy to measure at the terminals of the amplifier and so the resonance frequency of the driver. And with a digital crossover it is easy to adjust for a shift in resonance frequency. Even an online correction for a shift in resonance frequency is a possibility.