Test Bench: Tannoy HTS 200 Home Theater Speaker System
In the lab
Frequency response (at 2 meters) front left/right: 70 Hz to 16.1 kHz ±4.3 dB center: 120 Hz to 15.8 kHz ±4.0 dB surround: 112 Hz to 19.1 kHz ±3.6 dB subwoofer: 53 to 190 Hz ±1.5 dB
Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) front left/right: 85 dB center: 86 dB surround: 85 dB
Impedance (minimum/nominal) front left/right: 4.0/11 ohms center: 14/19 ohms surround: 3.3/10 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 72 dB center: 80 Hz at 73 dB surround: 80 Hz at 71 dB subwoofer: 25 Hz at 81 dB SPL 92 dB average SPL from 25 to 62 Hz 101 dB maximum SPL at 62 Hz bandwidth uniformity 91%
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 Tower's response with the speaker standing on the floor, averaged over a ±30º window with double weight at 30º (the most typical listening angle). The center-channel curve reflects the center speaker's response averaged over ±45º with double weight directly on-axis of the primary listener. The surround-channel curve shows the satellite's response averaged over ±60º. The center and surround speakers were measured on a 6-foot stand, which gives anechoic results down to approximately 200 Hz. Measurements for all speakers except subwoofers are taken at a full 2 meters, which emulates a typical listening distance, allows the outputs from the drivers in large speakers to fully integrate acoustically and, unlike near-field measurements, fully includes front panel reflections and cabinet diffraction.
Towers, Center, & Surrounds Measurements for the left/right front tower shows the typical floor-bounce notch centered at 230 Hz and considerable roughness at higher frequencies. Directivity of the towers, center, and surrounds is well controlled, however, with the result that all curves look practically the same. The center speaker's response begins to lobe as the microphone moves off-axis, with the disturbance becoming severe at listening angles of ±22.5º and beyond. The surround and center speakers' responses both measured smoother than the Tower's below about 4 kHz.
Subwoofer I measured the HTS subwoofer 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 subwoofer has modest output capability, falling off at roughly 10 dB per octave below the 101 dB SPL maximum the unit can deliver at 62 Hz.