JVC SXXSW6000 5.1 Surround System (Only $50) Page 4


Test Bench

Frequency response satellite 145 Hz to 20 kHz ±7.5 dB subwoofer 51 Hz to 220 Hz ±3 dB Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input) satellite 82 dB subwoofer N/A Impedance (minimum/nominal) satellite 5.8/6.5 subwoofer N/A Bass limits (lowest frequency and maximum SPL with limit of 10% distortion at 2 meters in a large room) subwoofer 56 Hz at 85 dB, 93 dB average SPL from 56 to 125 Hz, 99 dB maximum SPL at 100 Hz, bandwidth uniformity 88% The frequency-response curve of the satellite speaker is weighted to reflect how sound arrives at a listener's ears with normal speaker placement. Measurements of the satellite were made on a 6-foot stand at 1 meter, while the subwoofer's woofer and port were close-miked and their response summed.

Frequency response of the satellite is uneven, as it usually is for single-driver speakers. From the lowest range of the satellite's bandwidth, the response rises by several decibels up to a peak at 2.8 kHz, followed by a sharp dip centered at 5.7 kHz. The broad peak at 2.8 kHz - and the resulting lack of lower midrange response - are the cause of the satellite's perceived thin sound. The good news is that the satellites are fairly well-matched, varying by at most 1.5 dB and within 1 dB of each other at most frequencies.

Within the subwoofer's operating range, its response is impressively even, measuring effectively flat from 51 to 220 Hz. The range is limited, though - below about 56 Hz, distortion rises dramatically. Maximum output of 99 dB at 100 Hz is good for a sub of this size. Interestingly, and wisely, JVC has limited the gain of the 100-watt amplifier in the subwoofer. At many frequencies, we simply couldn't turn the sub up enough (or raise the level of the incoming test signal enough) to get to 10% distortion. In fact, at the peak output frequency, it was impossible to push the distortion past 1.8%.

The impedance of the satellite speakers runs a bit low for a system intended for use with inexpensive electronics. Furthermore, the very low sensitivity of 82 dB demands a great deal of amplifier power - more than four times what a typical speaker might need. This low sensitivity, coupled with the limited power handling of the satellites, makes it impossible to achieve high levels with this system.

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