The impulse response on the tweeter axis, shown in fig.8, is very good, with a time-coherent shape and a small amount of damped ultrasonic tweeter ringing. The time-coherence of the 3A is even clearer from the step response (fig.9), which reveals a very good step shape. The small plot wrinkles just below and above the 6 millisecond mark in fig.9 are probably reflections from the cabinet structure, and are also visible—though less obviously so—in fig.8.

Fig.8 Vandersteen 3A, impulse response on optimal axis at 50" (5ms time window, 30kHz bandwidth).

Fig.9 Vandersteen 3A, step response on optimal axis at 50" (5ms time window, 30kHz bandwidth).

The cumulative spectral-decay, or waterfall, plot is shown in fig.10. There's some delayed energy in the midrange—again, possibly reflections rather than resonances. The high-frequency response is, however, very clean (the ridge at about 15kHz is due to the computer monitor).

Fig.10 Vandersteen 3A, cumulative spectral-decay plot at 50" (0.15ms risetime).

All told, this is a very fine set of measurements of a very well-designed loudspeaker.—Thomas J. Norton