RBH T-2 Measurements and Analysis

This is a very impressive impedance/phase profile for such a complex multi driver speaker array.

The impedance looks almost resistive in nature from 100Hz out to 2kHz with a modest dip down to 4 ohms throughout the remaining audio band. Phase is extremely uniform maintaining a +- 30 degree window throughout the entire audio band, quite an achievement!

In my experience, I haven't measured a more benign loudspeaker load. Based on these measurements, and the high sensitivity of the design, any decent amplifier (even a rigid receiver) should be able to drive these speakers quite well.

Based on the low impedance profile of the T-1 at high frequencies, I recommend using low resistance cables (10AWG or less) to minimize potential frequency variations.

2.5 meter @ 20 deg room off-axis free field in room response summed with on-axis tweeter response above 11.5kHz 438 data points 3rd octave smoothed Figure 2a. T-2 System Summed Frequency Response

2.5 meter @ 30 deg off-axis quasi near field response 3rd octave smoothed

According to Shane, due to its rather unique driver topology, the T System cannot be measured accurately in the nearfield. Or in other words, due to the distance required for an accurate summation of the drivers, a measurement in the nearfield will not give an accurate representation of the performance of this loudspeaker. The measurements in Figures 2a and 2b were taken at a distance of 2.5m at 20 and 30 degrees off-axis, respectively. At 30 degrees off-axis the response of the tweeter above 10KHz rolls off accordingly and matches the off-axis response of the manufacturer data sheet as illustrated in Figure 6 .

Figure 4. FFT In Room Frequency Response of the T-2 System at Listening Position