Bookshelf Speaker Reviews

Satellite Sensitivity: 88.5 dB from 500 Hz to 2 kHz

Center Sensitivity: 89 dB from 500 Hz to 2 kHz

This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the Alpha B1 satellites (purple trace), SubSeries 5i subwoofer (blue trace), and Alpha C1 center channel (green 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 Alpha B1's listening-window response (a five-point average of axial and +/–15-degree horizontal and vertical responses) measures +1.27/–3.01 decibels from 200 hertz to 10 kilohertz. The –3-dB point is at 80 Hz, and the –6-dB point is at 54 Hz. Impedance reaches a minimum of 4.60 ohms at 238 Hz and a phase angle of –37.63 degrees at 132 Hz.

The Alpha C1's listening-window response measures +2.14/–1.30 dB from 200 Hz to 10 kHz. An average of axial and +/–15-degree horizontal responses measures +2.10/–2.29 dB from 200 Hz to 10 kHz. The –3-dB point is at 84 Hz, and the –6-dB point is at 63 Hz. Impedance reaches a minimum of 5.61 ohms at 6.1 kHz and a phase angle of –43.10 degrees at 2.1 kHz.

The SubSeries 5i's close-miked response, normalized to the level at 80 Hz, indicates that the lower –3-dB point is at 33 Hz and the –6-dB point is at 31 Hz. The upper –3-dB point is at 117 Hz with the LFE Input/ Crossover Bypass switch set to Active.—MJP