O3A Meter

O3A Meter

Host Support

Host TypeSupport
AAXYes
VST2Yes

Audio

ChannelsContent
Input16O3A
Output16O3A

Description

This plugin measures the sound level in an O3A stream. A breakdown by ambisonic order is provided, along with a history graph and the current overall level. Audio is passed through unchanged.

Meters

From left to right, the following displays are shown:

  1. Bar meter showing the current and recent peak level in order 0 (ACN channel 0 only).
  2. Bar meter showing the current and recent peak level in order 1 (ACN channels 1 to 3).
  3. Bar meter showing the current and recent peak level in order 2 (ACN channels 4 to 8).
  4. Bar meter showing the current and recent peak level in order 3 (ACN channels 9 to 15).
  5. History min/max graph of overall level (all 16 channels).
  6. Bar meter showing the overall current and peak level (all 16 channels).

Each bar meter shows the current RMS level in green, averaged using a 400ms rectangular window and translated to a decibel scale, along with a recent peak calculation using a 2s memory. The history graph shows the last three minutes of the overall level, displaying the range from minimum to maximum for each second.

The meters are all normalised so that a 0dBFS peak sine wave panned in any direction will produce a -3.01dB output. There is no sensitivity to frequency or direction. If you are interested in measuring loudness, you may wish to consider the O3A Meter - Karma plugin from the O3A Decoding Decoding library, which will produce comparable numbers when set to use LUFS units, subject to directional and loudness weighting.

For material that has been assembled by simple panning, the bar meters should be roughly in line with each other.

The plugin is available in the O3A Core plugin library.