Revel Ultima Studio loudspeaker Measurements part 3
Fig.8 Revel Ultima Studio, effect of tweeter control set to "+1dB" and "-1dB" positions, normalized to response at 50" on tweeter axis.
The step response (fig.9) is exactly what you'd expect from a speaker using high-order crossover filters. All of the drivers are connected with positive-going acoustic polarity, with the tweeter slightly leading the midrange unit and the woofers bringing up the rear.
Fig.9 Revel Ultima Studio, on-axis step response at 50" (5ms time window, 30kHz bandwidth).
The Revel's waterfall plot (fig.10) is one of the cleanest I have ever seen. The slight amount of delayed energy associated with the on-axis notch in the presence region suggests that this is some sort of diffraction/interference effect, which is why it disappears off-axis.
Fig.10 Revel Ultima Studio, cumulative spectral-decay plot at 50" (0.15ms risetime).
When I visited the Revel facility in L.A.'s San Fernando Valley last spring, I was enormously impressed with the know-how the company's engineering team had brought to bear on the problems traditionally associated with loudspeaker design and manufacture. The Revel Ultima Studio's measured performance pays tribute to that know-how.—John Atkinson