I didn't test the behavior of the rear-facing tweeter, but fig.8 shows the changes in the on-axis response associated with the front tweeter switched to its "+1dB" and "-1dB" settings. The treble region shelves up or down by almost exactly 1dB, and, as KR noted, the "-0.5dB" and "-1dB" settings will be very useful in adjusting the Studio's treble balance in relatively live rooms. Conversely, the slight boost setting will be appropriate in very large or very dead rooms.

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