Bookshelf Speaker Reviews

Measurements

Frequency response
• satellite 157 Hz to 20 kHz ±3.3 dB avg. 0°-30°, ±3.4 dB on-axis
• center 162 Hz to 20 kHz ±5.0 dB avg. 0°-30°, ±3.2 dB on-axis
• subwoofer 41 to 155 Hz ±3 dB

Sensitivity (SPL at 1 meter/1 watt)
• satellite 83.7 dB
• center 86.7 dB

Impedance (minimum/nominal)
• satellite 3.6/7 ohms
• center 3.1//7 ohms

Bass output, subwoofer (CEA-2010A standard)
• Ultra-low bass (20-31.5 Hz) average: 97.2 dB
    20 Hz: NA
    25 Hz: 93.1 dB
    31.5 Hz: 104.4 dB L
• Low bass (40-63 Hz) average: 114.7 dB
    40 Hz: 110.9 dB L
    50 Hz: 113.6 dB L
    63 Hz:118.1 dB L

Bass limits
• satellite 81.0 dB at 80 Hz
• center 86.7 dB at 63 Hz

I measured the frequency response of the satellite and center speakers from the HD Theater 600 using quasi-anechoic technique to remove the effects of reflections from nearby objects. I measured the satellite and center speakers with each placed atop a 2-meter-high stand. The microphone was placed at a distance of 1 meter, which with small speakers like this is adequate to capture the contributions of cabinet diffraction. I positioned the microphone directly in front of the tweeters, then adjusted the mike position slightly to get the flattest response. The curves you see in the chart represent the average of responses at 0°, ±10°, ±20°, and ±30°. Except as noted, the quasi-anechoic measurements were made without grilles and smoothed to 1/12^th octave. Bass response of both speakers was measured using close-miking technique, with the mike positioned about 6mm from each woofer. Bass response measurements were spliced to the quasi-anechoic measurements at 160 Hz. Frequency response of the subwoofer was measured using ground plane technique with the microphone on the ground 2 meters from the sub, smoothed to 1/3^rd octave. Results are normalized to 0 dB at 1 kHz for the satellite and center, and to a peak of +3 dB for the sub. All frequency response measurements were made with a Clio FW audio analyzer then imported into a LinearX LMS analyzer for post-processing.

The satellite is one clean-measuring little speaker. Except for that dip at 2.6 kHz, it’s almost dead flat through its entire operating range. Even way outat ±45° and ±60°, there’s just a mild treble roll-off in addition to that 2.6 kHz dip. Adding the grille has more effect than I expected; it reduces treble response by -1.5 to -2.5 dB below 10 kHz, and by as much as -6.3 dB at higher frequencies.

The center is similarly impressive on-axis, but it shows some extreme interference effects between its midwoofers even at just ±20° off-axis. At ±30°, there’s a -21 dB dip at 3.3 kHz. Similar effects appear in the 1.5 to 1.8 kHz range at ±45° and ±60°. I’m a little surprised at this, because a tiny center speaker with small midranges usually has much less driver interference than a larger center speaker; my guess is Klipsch sacrificed off-axis response and gained power handling by going with a fairly high crossover point. Acoustical effects of the center speaker’s grille are comparable to those of the satellite’s grille.

Even the cheapest A/V receiver on Amazon could drive these speakers to loud levels without trouble. For the satellite, minimum impedance is 3.6 ohms at 390 Hz with a phase angle of -6°. For the center, it’s 3.1 ohms at 400 Hz/-3°. Anechoic sensitivity (measured on-axis outdoors, average output from 300 Hz to 10 kHz at 1 meter with a 2.83-volt RMS signal), is pretty good for both speakers; figure an additional +3 dB of output in-room.

Although neither the satellite nor the center has much measured bass response, the bass power output measurements are surprisingly high for such tiny midwoofers, indicating that the speakers may blend better with the sub than their frequency response measurements suggest.

CEA-2010A output measurements for the subwoofer were taken at 3 meters then scaled the results up per CEA-2010A requirements so that they are equivalent to 1-meter results. Measurements with an L next to them are those in which the maximum output was determined by the sub’s internal limiter. Averages are calculated in pascals. I subtracted -18 dB from the 25 Hz measurement to get a 20 Hz figure for calculating the ultra-low bass average.

For a sub included with an HTiB system, this one’s shockingly good. In the low bass (40-63 Hz) octave, it’s competitive with many larger, sold-separately subs. It also has ample output down to 25 Hz. (I couldn’t get enough output for a measurement at 20 Hz.) Unusually, the limiter is operational even down to 31.5 Hz, something I normally expect to see only in high-end monster subs from companies such as SVSound; that suggests you’ll hear less distortion. However, it’s worth noting that the first burst in the series of tone bursts I use for this measurement always sounded more distorted than the rest, so maybe the limiter’s a little slow. Combined low-pass function of the internal crossover and the driver is -14 dB/octave at 80 Hz.

—Brent Butterworth