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K-array Mastiff KM312P: SPL & coverage at 12 m

Problem. A single K-array Mastiff KM312P point-source cabinet is being considered to cover a 25 x 18 m live event space from one flown or stacked position. The real question is whether its rated output and dispersion still deliver an adequate level at a listener 12 m out, not just at the mix position.

Answer. At a 12 m listener position and 60% drive, this preset computes an SPL of approximately 114 dB, comfortably under the roughly 116 dB available at full output from the same distance. The 100 x 30 degree dispersion gives a -6 dB horizontal coverage half-width of approximately 14.3 m, which reaches past the 12 m listener with headroom to spare.

02 / In depth

How this preset reads — the engineering view.

The KM312P is rated at 138 dB SPL at 1 m. Because SPL falls with the inverse square of distance, that figure drops fast as the listener moves away: at 12 m and full output the model shows approximately 116 dB, and at the preset's 60% drive level approximately 114 dB reaches the listener position.

The cabinet's 100 x 30 degree (H x V) nominal dispersion is what sets the approximately 14.3 m horizontal coverage half-width at -6 dB in this preset. The wide horizontal pattern favours even near-field fill across a room this width, but as a passive enclosure the KM312P depends entirely on a matched amplifier channel to reach its rated output.

Use the planner by dragging the listener distance and drive level sliders and watching the SPL figure move in response. Box count shown alongside is only a front-coverage area estimate; SPL adequacy at a given listener position is a separate check and should be read from the SPL result, not inferred from box count alone.

The planner does not model room reverberation or RT60, coverage zoning across multiple areas of a room, subwoofer pairing or crossover, array mechanical rigging, or DSP and delay-line tuning between cabinets. Those remain separate design steps beyond this single-cabinet SPL and coverage estimate.

What this preset deliberately does not solve

  • Figures are free-field inverse-square estimates from the rated 1 m SPL; they do not account for room reflections, absorption, or crowd absorption losses.
  • Coverage half-width reflects the nominal 100 x 30 degree dispersion figure only; real-world pattern control can vary with frequency and mounting angle.
  • This is a single-cabinet estimate; multi-box arrays, delays, and subwoofer integration change the effective coverage and are not modelled here.

How this preset differs from its siblings

Other point-source options in the catalogue carry different rated SPL and dispersion figures, which shift both the safe listener distance and the coverage half-width the planner computes. The KM312P's 138 dB rating and comparatively wide 100 x 30 degree pattern suit a wide, single-position live event footprint rather than a narrow-throw or higher-output cabinet, which is why it needs its own preset rather than sharing one with other models.

02 / What that means, drawn

Plan view, drawn to one scale in both directions. The room is 25.00 m deep by 18.00 m wide, with the cabinet on the front wall and the listener 12.00 m down the axis. K-array Mastiff-KM312P stage monitor has a nominal horizontal pattern of 100°, so the covered shape is a wedge whose apex is at the CABINET, not a circle around the listener. The wedge is drawn at half that angle either side of the axis. At the listener's distance that wedge is 28.60 m across — 14.30 m either side of the axis. That width is the published figure, and it is the only coverage quantity this tool establishes. The room is 18.00 m wide there, so one cabinet covers the full width with 10.60 m to spare across the two edges combined. The wedge is the nominal beamwidth drawn with straight edges. It is not a measured -6 dB contour, and it is a HORIZONTAL quantity only: no vertical coverage, and no covered area, is claimed here. This cabinet's vertical pattern is 30°, and the difference between the two is exactly why a single circular figure would misstate the covered patch.

This preset’s geometry, drawn to one scale in both directions from the same derivation the calculator below uses. The wedge is K-array Mastiff-KM312P stage monitor’s nominal 100° horizontal pattern, not a measured contour, and no vertical coverage or covered area is claimed. Move the controls below to change it.

03 / Hydrated calculator

Try the configuration — live.

The calculator below is preloaded with this preset’s state. Adjust any input — your URL stays shareable.

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