The SoundMeter Pro Subscription includes additional tools and features for sound level analysis and data acquisition, plus ongoing hardware support, such as periodically updated nominal microphone sensitivities for built-in microphones on Apple devices, updated nominal voltage sensitivities for select audio input devices, and automatic calibration for audio input devices that include built-in sensitivity information.

SoundMeter Pro includes:

• Level Meter
  • Lp, Leq, Lx sound levels
  • Standard Flat, A, C frequency weighting
  • Standard Fast, Slow, Impulse time weighting
  • Data logging. Data can be logged as often as every 0.1 seconds for up to 8 hours, every second for up to 72 hours, or every 10 seconds for up to two weeks.
  • Event notifications
• Max Levels Meter
  • Traffic-light-style meters make it easy to monitor 2 separate sound level thresholds in 2 independent user-defined frequency bands.
  • Define lower (warning) and higher (limit) sound level thresholds for overall (full audio band) levels as well as for individual octave frequency bands.
  • Store user-defined thresholds in files for later recall.
  • View auxiliary sound level or octave spectrum display with the device in landscape orientation.
  • Event notifications
• Noise Dosimeter
  • 8-hour Noise Dose, Projected Dose, TWA calculations
  • Criterion Levels: 80, 85, 90 dB
  • Exchange Rates: 3, 4, 5 dB
  • Data logging. Data can be logged as often as every 0.1 seconds for up to 8 hours, every second for up to 72 hours, or every 10 seconds for up to two weeks.
  • Event notifications
• Octave Analyzer (RTA)
  • Lp, Leq, Lx sound levels
  • Supports whole or 1/3-octave frequency bands
  • Standard Flat, A, C frequency weighting
  • Standard Fast, Slow, Impulse time weighting
  • NC, RNC, and NR references curves, NC, SIL, and NR values
  • Data logging. Data can be logged as often as every 0.1 seconds for up to 8 hours, every second for up to 72 hours, or every 10 seconds for up to two weeks.
  • Event notifications
• Data Recorder
  • Supports up to 8 channels
  • Live monitoring of recorded data
  • Metadata (including calibrated sensitivity) embedded in audio file (AIF, CAF, WAV), optionally saved in separate data file
• Signal Generator
  • Left and right outputs assigned to arbitrary hardware output channels
  • Random and pseudorandom (periodic) noise sequences with white or pink spectrum
  • Linear and logarithmic frequency sweeps
  • Dual periodic waveforms with arbitrary frequency and phase difference

Regarding your subscription:

• Payment will be charged to your iTunes Account at the end of the free trial period, unless you have turned off automatic renewal. If the free trial has already expired, payment will be charged at confirmation of subscription purchase.
• Subscription automatically renews unless auto-renew is turned off at least 24 hours before the end of the current period.
• Your account will be charged for renewal within 24 hours prior to the end of the current period for the same price as the current period (shown above).
• You may manage your subscriptions and auto-renewal may be turned off by going to your iTunes Account Settings after purchase (Account Settings may be accessed in the App Store app on your iOS device).
• Any unused portion of the free trial period will be forfeited when you purchase a subscription, where applicable.