LABORATORY TEST REPORT
Newport Test Labs first tested the frequency response of the Dynaudio Sub 6 subwoofer using a near-field measurement technique that simulates the response that would be obtained if it were measured in an anechoic chamber, effectively eliminating any room effects. The results for three settings of the crossover control are shown in Graph 1.
In Graph 1 you can see that with the Bypass setting, the frequency response is extremely linear and extended, stretching from 17Hz to 195Hz ±3dB (black trace). With the crossover set to 120Hz, the slightly earlier roll-off removes the slight peak at around 80Hz to 100Hz that’s present in the Bypass response, and means that the overall response for this setting is 16Hz to 123Hz ±3dB (green trace). When the crossover control is set to its minimum position, the response measured by Newport Test Labs for the Dynaudio Sub 6 was 16Hz to 39Hz ±3dB (blue trace).
Graph 2 shows the in-room far-field response of the Dynaudio Sub 6 subwoofer when measured by Newport Test Labs using a pink noise test signal. This is a far more difficult test signal to reproduce than the test signal used to produce Graph 1 because with pink noise the drivers are required to simultaneously produce all audio frequencies across their pass-band, and in this case the Dynaudio was also not positioned alongside a wall, where it was designed to be placed to maximise bass output, but instead positioned in the centre of the measuring room. As such, it’s really a ‘worst-case measurement’. (Note also that the horizontal scale has been changed, so that the left-most side of the graph represents a frequency of 20Hz, rather than 10Hz, as in Graph 1.)
You can see that the combination of the sub-optimal room positioning and the more difficult test signal have meant the low-frequency response rolls off rather earlier, so that in Bypass mode the measured response is 45Hz to 250Hz ±3dB, and with the crossover set to 120Hz, it’s 38Hz to 160Hz ±3dB. When the crossover is set to minimum (40Hz), the measured response that’s graphed extends from 20Hz to 60Hz ±3dB (blue trace). This test shows that there will always be limits to subwoofer performance imposed by amplfier power, cabinet volume, driver surface area and cone excursion.
However, because the two different measurements made by Newport Test Labs show both ‘best case’ (Graph 1) and ‘worst case (Graph 2) performance, it’s obvious that the actual performance you will obtain in your own room will lie somewhere in between, depending on the acoustics of your room and where you position the Dynaudio Sub 6 in that room. The good news is that anywhere in between these two results actually guarantees that you can expect very good performance indeed. Steve Holding