Test Bench: Triad In-Room Gold Home Theater Speaker System
In the lab
Frequency response (at 2 meters) front left/right: 100 Hz to 13.7 kHz ±4.2 dB center: 100 Hz to 9.4 kHz ±3.1 dB surround: 92 Hz to 16.7 kHz ±5.4 dB subwoofer: 24 to 117 Hz ±2.3 dB
Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) front left/right: 91 dB center: 90 dB surround: 81 dB
Impedance (minimum/nominal) front left/right/center: 2.2/4 ohms center: 2.8/5 ohms surround: 3.2/4 ohms
Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room) front left/right: 50 Hz at 86 dB center: 40 Hz at 83 dB surround: 80 Hz at 88 dB subwoofer: 20 Hz at 97 dB SPL 109 dB average maximum SPL from 25 to 62 Hz 114.3 dB maximum SPL at 62 Hz
All of the curves in the frequency-response graph are weighted to reflect how sound arrives at a listener's ears with normal speaker placement. The curve for the left/right front channels reflects the response of a vertically oriented Gold LCR averaged over a ±30° window. The center-channel curve reflects the response of a horizontally placed Gold Center averaged over ±45°, with double weight directly on-axis. The surround-channel curve shows the Gold Surround's response averaged over ±60°. All acoustical measurements were taken at a full 2 meters distance to allow true acoustical summation of individual radiating elements, front-panel reflections, and cabinet diffraction.
Measurements revealed the Gold LCR to be fairly directional, meaning that high-frequency response rolls off more quickly than usual as the microphone moves off axis. From the on-axis, primary listening position, the speaker response begins falling off below 200 Hz and above 4 kHz at 2 to 3 dB per octave. The Gold Center's response has a similar shape, with a faster roll-off at wide listening angles, but is completely free of the off-axis lobing common to most horizontally arrayed center speakers. Both speakers have good sensitivity and an adequate bass limit, with the left/right satellites delivering 86 dB at 50 Hz and the center putting out 83 dB at 40 Hz. The on-wall surround has a deep on-axis null (-33 dB at 1.3 kHz), which is a desired characteristic for a dipolar surround speaker. Care should be taken with all three speakers to choose electronics that can handle low-impedance loads.
I measured the subwoofer's frequency response and bass limits with it placed in the optimal corner of a 7,500-cubic-foot room and driven by the accompanying RackAMP through the Subwoofer Input. In a smaller room, users can expect 2 to 3 Hz deeper extension and as much as 3 dB greater sound-pressure level (SPL). Frequency response was taken ground plane at 0.5 meter, which is far enough true acoustical summation of individual radiating elements at low frequencies.
This subwoofer is one of the most potent I've had the opportunity to test in recent years. It delivered 110 dB SPL or more at every frequency greater than 25 Hz and 97 dB SPL at 20 Hz with less than 10% distortion. It even makes an attempt at 16 Hz (where it achieves 84 dB SPL), but noise burps from the protection circuitry spoils the try. There is also an out-of-band artifact at 400 Hz that is less than 5 dB below in-band output, meaning that the system should always be used (as it normally would be) with a low-pass crossover.