the driver would reproduce in a similarly sized sealed box. The enclosure resonance has a secondary benefit in that it limits cone movement in a band of frequencies centered around the tuning frequency, reducing distortion in that frequency range. Ported cabinet systems are cheaper than a passive radiator speaker with the same performance; whereas a passive radiator system requires one or two "drone cone" speakers, a ported system requires only a hole or port and a length or tubing. Limitations Compared to closed-box loudspeakers, bass reflex cabinets have poorer transient response, resulting in longer decay times associated with the bass notes. Some example step responses for various high-pass filter functions are shown in the relevant figure, where each filter has an identical −3 dB cut-off frequency of 50 Hz. In that figure, (a) represents the step response of a conventional B4 vented box alignment, while (b) represents the step response of a B2 closed-box alignment with Q = 0.7071. The transient response of a vented-box loudspeaker can be improved by choosing a QB3 alignment similar to (c), which results in a more well damped transient response than that produced by the B4 alignment. However, a C4 vented-box alignment similar to (e) results in a less well damped transient response. In order to achieve their bass output, ported loudspeaker enclosures stagger two resonances: one from the driver and the boxed air, and another from the boxed air and the port. At the vent tuning frequency, the output from the port is the primary source of sound output, as the displacement of the woofer is at a minimum. This comprises a more complex, higher-order system than an equivalent closed-box loudspeaker enclosure. The interaction between the two resonances results in a system that possesses less damping and increased time delay (increased group delay). Due to the latter, a flat steady-state bass response does not occur at the same time as the rest of the sonic output at higher frequencies in the operating region. Instead, it starts later (lags) and the lag increases, accumulating over time as a longish resonant "tail" arriving behind the main "body" of the acoustic signal. As a result of their electrodynamic characteristics, ported enclosures, which are well approximated as 4th-order high-pass filter systems, generally result in poorer transient response at low frequencies than do closed-box loudspeaker systems, which are 2nd-order high-pass filter systems. Another trade-off for this augmentation is