Ceiling mic coverage calculator
How many ceiling mics does this room need? Enter the ceiling height, the pickup angle and the area to cover.
Coverage circle per mic (diameter)
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Area per mic
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Grid spacing for no gaps
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Mics needed
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How it works
coverage radius = (ceiling height − head height) × tan(pickup angle ÷ 2)
no-gap grid spacing = radius × √2
no-gap grid spacing = radius × √2
A ceiling mic's pickup is a cone pointing down. Where the cone meets talker head height, it draws a circle on the room. A 90° mic 5 ft above the talkers covers a circle 10 ft across.
Circles don't tile, so to leave no dead spots the mics are laid out on a square grid where each square fits inside one circle. The calculator rounds up the number of rows and columns.
Field notes
- Seated head height is usually taken as about 4 ft (1.2 m). Use standing height for rooms where people present on their feet.
- Beamforming ceiling arrays publish their own coverage. For array mics, the manufacturer's coverage figure for your ceiling height overrides this geometry. Use this calculator for conventional ceiling mics and as a sanity check.
- Higher isn't better. Every doubling of distance to the talker costs about 6 dB of level, so a high ceiling picks up more room and HVAC relative to voice. Drop the mics on pendants in tall rooms.
- Keep mics away from ceiling speakers and diffusers. Air noise and speaker bleed both work against the echo canceller.
- Cover where people sit, not the whole room. Size the area to the table plus the chairs, not wall to wall.
FAQ
What pickup angle should I use?
Use the angle the manufacturer gives as the mic's usable or "coverage" angle, not the polar pattern's full width. If you only have a polar plot, the angle where response is about 6 dB down is a reasonable starting point.