Floorstanding Speaker Systems

L/R Sensitivity: 90 dB from 500 Hz to 2 kHz

Center Sensitivity: 90 dB from 500 Hz to 2 kHz

Surround Sensitivity: 86.5 dB from 500 Hz to 2 kHz

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

The Spark's listening-window response (a five-point average of axial and +/–15-degree horizontal and vertical responses) measures +1.64/–6.94 decibels from 200 hertz to 10 kilohertz. The –3-dB point is at 82 Hz, and the –6-dB point is at 54 Hz. Impedance reaches a minimum of 5.14 ohms at 186 Hz and a phase angle of –29.53 degrees at 96 Hz.

The Celsius's listening-window response measures +1.50/–3.48 dB from 200 Hz to 10 kHz. An average of axial and +/–15-degree horizontal responses measures +1.38/–4.14 dB from 200 Hz to 10 kHz. The –3-dB point is at 94 Hz, and the –6-dB point is at 65 Hz. Impedance reaches a minimum of 4.44 ohms at 198 Hz and a phase angle of –56.97 degrees at 80 Hz.

The Step's listening-window response measures +0.56/–6.08 dB from 200 Hz to 10 kHz. The –3-dB point is at 68 Hz, and the –6-dB point is at 46 Hz. Impedance reaches a minimum of 4.37 ohms at 203 Hz and a phase angle of –41.55 degrees at 91 Hz. It's unusual that the bass extension numbers for the surrounds are lower than for the towers. There are several factors at play here, including the fact that the towers are tuned to 51 Hz, while the surrounds are tuned to 40Hz.—MJP