Bookshelf Speaker Reviews

• Beta 10 L/R Sensitivity: 86 dB from 500 Hz to 2 kHz

• Beta C250 Center Sensitivity: 83.5 dB from 500 Hz to 2 kHz

• Beta ES250 Surround Sensitivity: 83 dB from 500 Hz to 2 kHz

This graph shows the quasi-anechoic (employing close-miking of all woofers) frequency response of the Beta 10 L/R (purple trace), CSW-10 subwoofer (blue trace), Beta C250 center channel (green trace), and Beta ES250 surround (red trace). All passive loudspeakers were measured at a distance of 1 meter with a 2.83-volt input and scaled for display purposes.

The Beta 10's listening-window response (a five-point average of axial and +/–15-degree horizontal and vertical responses) measures +2.09/–3.11 dB from 200 Hz to 10 kHz. The –3dB point is at 64 Hz, and the –6dB point is at 56 Hz. Impedance reaches a minimum of 6.51 ohms at 216 Hz and a phase angle of –46.87 degrees at 111 Hz.

The Beta C250's listening-window response measures +2.66/–2.44 dB from 200 Hz to 10 kHz. An average of axial and +/–15-degree horizontal responses measures +2.79/–2.77 dB from 200 Hz to 10 kHz. The –3dB point is at 72 Hz, and the –6dB point is at 61 Hz. Impedance reaches a minimum of 5.56 ohms at 14.3 kHz and a phase angle of –69.35 degrees at 3.7 kHz.

The Beta ES250's three-face averaged response in dipole mode measures +5.41/–3.78 dB from 200 Hz to 10 kHz. The –3dB point is at 81 Hz, and the –6dB point is at 71 Hz. Impedance reaches a minimum of 3.57 ohms at 20 kHz and a phase angle of –72.63 degrees at 111 Hz.

The CSW-10's close-miked response, normalized to the level at 80 Hz, indicates that the lower –3dB point is at 29 Hz and the –6dB point is at 27 Hz. The upper –3dB point is at 280 Hz in LFE mode.—MJP