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Open Sound Meter

ChurchBoard receives Open Sound Meter (OSM) Remote API level packets directly on the production LAN. In OSM, open the Wi-Fi menu and enable Remote API Server. ChurchBoard joins the multicast group 239.255.42.42:49007, so the OSM machine and ChurchBoard machine must be on the same multicast-enabled network segment.

Available live levels

The verified OSM levels message contains these values:

{
  "api": "Open Sound Meter",
  "message": "levels",
  "data": {
    "A": {"Fast": -61.6, "Slow": -63.9},
    "B": {"Fast": -60.0, "Slow": -62.5},
    "C": {"Fast": -58.2, "Slow": -59.1},
    "Z": {"Fast": -57.7, "Slow": -61.0}
  }
}

These Remote API values use OSM's internal full-scale reference. OSM's own SPL meter adds its fixed 140 dB SPL offset when rendering them. ChurchBoard applies the same conversion, so an API value of -69 is displayed as 71 dB SPL, and values at or below the -140 floor display as 0 dB SPL.

In the Open Sound Meter widget settings, select A-, B-, C-, or Z-weighting and a Fast or Slow response. The widget shows that exact live OSM value. In Setup, choose the weighting and response used for downloadable service reports; that selection is kept consistent for the entire report.

OSM broadcasts a separate levels packet for every active source. ChurchBoard lists those sources by their OSM name in Setup. Select the same measurement source you are viewing in OSM. Until a source is selected, ChurchBoard follows the first OSM source it detects and does not switch based on the measured level. Explicit selection is recommended whenever OSM has multiple sources.

The dashboard performs no smoothing, rolling average, peak hold, microphone calibration, or automatic source selection on the live value. It displays the chosen A/B/Z Fast/Slow field from the chosen source after applying only OSM's own fixed SPL display reference described above. Historical averaging exists only in downloaded service reports and never feeds the live widget.

Service reports

When report recording is enabled, ChurchBoard correlates each selected OSM level sample to the active Planning Center LIVE item. The Open Sound Meter widget provides downloads for the service graph and per-item average CSV.

RTA

OSM's verified multicast levels message does not include real-time-analysis (RTA) spectrum bands. ChurchBoard therefore does not render an RTA from that message. RTA support can be added later if OSM exposes and we capture a stable multicast packet format for spectrum data.

The optional tools/osm_bridge.py helper remains useful for relaying OSM levels to external WebSocket consumers, but ChurchBoard itself does not need it for normal OSM monitoring.