Meridian Digital Theatre surround-sound music system Measurements DSP6000

Sidebar 5: Measurements Meridian DSP6000

For logistic reasons, I measured only the Center version of the DSP6000. However, as this model differs from the side version only in the angle of the head-unit's sidewalls, this set of measured data should be representative of all three speakers.

The DSP6000 appeared to be around 0.5dB more sensitive than the DSP5000 with the same noise signal at -12dBFS and a volume setting of "70." The difference is inconsequential. The balance averaged across a 30 degree horizontal window on the tweeter axis (fig.18) was almost as flat as the DSP5000's, but with slightly less energy in the mid-treble. An alternative way of looking at this balance would be to regard it as being slightly forward in the upper midrange. All things being equal, whether this or the presence depression is perceived by the listener will depend on personal taste and the recordings played.

Fig.18 Meridian DSP6000C, anechoic response on tweeter axis at 50", averaged across 30 degrees horizontal window and corrected for microphone response, with the complex sum of the nearfield woofer and midrange responses plotted below 300Hz.

Again, the tweeter features a large rise at its ultrasonic resonance. In the bass, the '6000 offers extension at full level down to 30Hz, with then a steeper rollout than is usual from a sealed-box alignment. The effect of the tilt control appeared identical to that of the smaller speaker, so is not shown.

The DSP6000's horizontal dispersion (fig.19) was also similar to that of the '5000, which implies excellent matching of the two speakers in a surround-sound system. And again, in all but very large or acoustically dead rooms, the flare in the speaker's radiation pattern at the bottom of the tweeter passband will tend to compensate for the lack of on-axis energy in the same region, resulting in a neutral perceived balance overall. Vertically (fig.20), the DSP6000's balance doesn't change significantly as long as the listener's ears are between 51" (the tweeter axis) and 39" from the floor. For a standing listener, a suckout appears at the upper crossover frequency (2.5kHz), while the treble tilts up. But in any case, the speaker's optimal axis can be tilted down by adjusting the relative time delay between the drive-units.

Fig.19 Meridian DSP6000C, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90 degrees-5 degrees off-axis, reference response, differences in response 5 degrees-90 degrees off-axis.

Fig.20 Meridian DSP6000C, vertical response family at 50", from back to front: differences in response 10 degrees-5 degrees above tweeter axis, reference response, differences in response 5 degrees-20 degrees below tweeter axis.