Tower Speaker Reviews

The sensitivity of the TZ-C700 center channel is 91.3dB. This is respectably high, and significant only in that it will require just under twice as much power as the 2.3-dB-more-sensitive TZ-F700 to produce the same output level. For reasons we could not determine, the TZ-C700 cut in and out during the impedance measurements (it still functioned normally in normal operation), so no impedance curve is presented here. However, since the TZ-C700 and TZ-F700 use the same IRIS driver, it's reasonable to assume that, above 450Hz, the TZ-C700's impedance is at least similar to that of the larger loudspeaker.

The TZ-C700's frequency response in the range covered by the IRIS is shown in Fig.3. The response is very similar to that of the TZ-F700, though with a slight lack of energy in the upper presence region at around 2kHz. The lateral dispersion is excellent up to 2kHz, but more limited above that frequency than the TZ-F700's. This is clearly due to the difference between the latter's narrow front baffle and the center channel's wide one.

Fig.3 Pioneer TZ-C700, anechoic response on upper-midrange tweeter axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response.

The impulse and step responses of the TZ-C700 are good, and quite similar to those measured in the TZ-F700. As with the latter, the TZ-C700 is not time-coherent. The waterfall/delayed resonance performance of the center channel is clean, and similar to that of the TZ-F700.

The TZ-F700 and the TZ-C700 exhibited very different vibration signatures when measured with an accelerometer taped to their cabinet walls. Measured on its curved side panel, the TZ-F700's cabinet proved extremely well damped: Fig.4 indicates only one vibration mode, and that very low in level. The TZ-C700, on the other hand, measured on its curved top panel, has very-high-level vibration modes (Fig.5). While the audible effects of these modes are not dramatic, I comment in the review on a slight boxiness and warmth in the system, much of which appears to come from the center channel. These characteristics could well relate to the latter's cabinet-resonance modes. The TZ-C700 is still a more than acceptable mate for a pair of TZ-F700s, but might profit noticeably from refinements to its cabinet damping.

Fig.4 Pioneer TZ-F700, cabinet resonance signature, measured on center of side panel. (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz.)

Fig.5 Pioneer TZ-C700, cabinet resonance signature, measured on center of top panel. (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz.)

The TZ-C700's rather lively cabinet aside, this is a fine set of measurements, indicating two loudspeakers clearly designed to meet high-end audio standards.—TJN