Test Bench: NHT Verve Home Theater Speaker System
In the lab
Frequency response (at 2 meters) front left/right: 99 Hz to 18.1 kHz ±3.3 dB center: 99 Hz to 18.1 kHz ±3.0 dB surround: 101 Hz to 18.5 kHz ±3.1 dB subwoofer: 42 to 252 Hz ±3.6 dB
Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) front left/right/center: 87 dB surround: 85 dB
Impedance (minimum / nominal) front left/right/center: 5.2 / 8 ohms surround: 4.7 / 11 ohms
Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room) front left/right/center: 80 Hz at 80 dB surround: 80 Hz at 80 dB subwoofer: 25 Hz at 81 dB SPL 95 dB average SPL from 25 to 62 Hz 104 dB maximum SPL at 50 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 V Large was averaged over a ±30° window (the most typical listening angle). The center-channel curve reflects a horizontally positioned V Large's response averaged over ±45°, with double weight directly on-axis of the primary listener. The surround-channel curve shows a V Small's response averaged over ±60°.
I measured the speakers on a 6-foot stand, which gives anechoic results to approximately 200 Hz. All measurements except those for subwoofers are taken at a full 2 meters, which emulates a typical listening distance, allows the outputs of large speakers to fully integrate acoustically, and, unlike near-field measurements, fully includes front-panel reflections and cabinet diffraction.
In terms of measurements, this is about the best-performing boxed speaker system I've seen, with flat, controlled directivity that almost seems too good to be true. The response graphs for the V Large, whether vertically or horizontally deployed, are virtually identical. That's because the ingenious coaxial midrange/tweeter array avoids the sometimes spectacular off-axis lobing characteristic of most horizontally-arrayed center-channel speakers. Thus, all the speakers in this system should have nearly identical sound when heard from the primary listening position. There is a small degree of lobing at radiating angles greater than 30 degrees, but the overall sound delivered to listeners is blemished by only small irregularities from any channel. The speakers have a smooth but slightly up-tilted response that is about 2 dB "hot" above 8 kHz, though this is easily corrected by a small reduction of the treble control if desired.
I measured the V Woofer's bass limits with it set to maximum bandwidth and placed in the optimal corner of a 7,500-cubic-foot room. In a smaller room, users can expect 2 to 3 Hz deeper extension and as much as 3 dB greater sound-pressure level (SPL). The V-woofer had limited low-frequency dynamics, but the extended upper-frequency response (all the way to 250 Hz) allows for a good match with the small satellites it's mated with. SPL averaged 95 db from 25 to 62 Hz and hit a maximum SPL of 104 dB at 50 Hz (within our 10% distortion limit).