Bookshelf Speaker Reviews

Center Sensitivity: 88.5 dB from 500 Hz to 2 kHz

Surround Sensitivity: 85 dB from 500 Hz to 2 kHz

This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the Ultra Bookshelf L/R (purple trace), Ultra Center (green trace), Ultra Surround (red trace), and SB12-NSD subwoofer (blue trace). All passive loudspeakers were measured with grilles at a distance of 1 meter with a 2.83-volt input and scaled for display purposes.

The Ultra Bookshelf’s listening-window response (a five-point average of axial and +/–15-degree horizontal and vertical responses) measures +1.56/–3.20 decibels from 200 hertz to 10 kilohertz. The –3-dB point is at 56 Hz, and the –6-dB point is at 49 Hz. Impedance reaches a minimum of 4.61 ohms at 200 Hz and a phase angle of –45.33 degrees at 98 Hz.

The Ultra Center’s listening-window response measures +1.93/–2.97 dB from 200 Hz to 10 kHz. An average of axial and +/–15-degree horizontal responses measures +2.05/–3.04 dB from 200 Hz to 10 kHz. The –3-dB point is at 60 Hz, and the –6-dB point is at 51 Hz. Impedance reaches a minimum of 4.03 ohms at 93 Hz and a phase angle of +28.96 degrees at 1.4 kHz.

The Ultra Surround’s three-face averaged response in the default Bipole mode measures +1.86/–4.62 dB from 200 Hz to 10 kHz. The –3-dB point is at 71 Hz, and the –6-dB point is at 60 Hz. Impedance reaches a minimum of 3.96 ohms at 195 Hz and a phase angle of –40.50 degrees at 98 Hz.

The SB12-NSD’s close-miked response, normalized to the level at 80 Hz, indicates that the lower –3-dB point is at 22 Hz and the –6-dB point is at 20 Hz. The upper –3-dB point is at 203 Hz with the Low Pass control set to maximum.—MJP