SENTINEL
Surround Audio Program Monitor

Identifies level and loudness problems

• Measures level on up to 8 channels
• Simultaneously measures stereo and mono downmix levels of a surround program
• Measures loudness to ITU-R BS.1770 (LeqLRB)

Identifies program compatibility problems

• Directly measures stereo & mono compatibility
• Measures LFE bandwidth & phase compatibility

Identifies signal chain problems

• Dropout detection
• Dead channel detection
• Hum detection
• Extracts digital audio metadata and compares:
  - to interface signal
  - to signal characteristics
  - across surround channels

Easily understood display

• Generates simple bargraph and text displays
• All measurements displayed as good=green, marginal=yellow, bad=red
• Network accessible with standard browsers
• Generates user-defined alarms (local, remote and e-mail)

Integrates easily into larger systems

• Retains previous 24 hours of data for review or download to long term storage
• Clock / calendar for time & date reference
• LTC input for correlating results with program
• Internal sensor reports rack temperature
• 6 DC inputs for monitoring external parameters (line voltage, security, transmitter power, etc.)
• Log file translator produces ASCII data for user developed post processing

The shift to surround-sound from stereo brings additional complexity in the audio monitoring and quality assurance functions. The growth associated with these changes has also forced many people unfamiliar with the subtleties of audio into roles where they are responsible for ensuring its quality.

Simplistic multichannel audio level metering products are available from a wide range of manufacturers. Though important, managing signal levels is widely recognized to be only a small part of the task.

Numerous other problems can occur with an audio feed, discovery and correction of which traditionally necessitated continuous aural checks by skilled staff. Intermittent or dead channels, incorrect signal routing, channel reversal, hum, and many other conditions can result in severe dissatisfaction for listener, advertiser, sponsor and management.

The broadcast transition to digital audio has added additional potential for trouble involving incompatibilities in sample rates, word length, emphasis, metadata and more. Along with the shift to low bit-rate coding - with its sensitivity to signal clipping - and the increased dependence on metadata; the potential for audio errors reaching the listener is significantly increased.

The Qualis Audio SENTINEL was designed to address the compound needs of increased monitoring requirements, decreased personnel availability and shrinking budgets. It uses advanced signal processing algorithms to directly answer broadcast user’s fundamental questions, rather than merely displaying information requiring further analysis by experienced personnel. Coupled with a truly intuitive human interface and a hardware interface designed to fit into existing infrastructure, the SENTINEL allows significant reductions in operating costs while improving the quality of delivered audio.

The savings in personnel costs and lower error rates can be dramatic. The resulting return on investment can generally be measured in months or even weeks.

Also see the Broadcast Engineering article on Audio Monitoring.