Originally featured on BroadcastEngineering.com
RTW SurroundMonitor 10800X provides loudness metering
RTW has released a software upgrade that will enable qualified SurroundMonitor 10800X devices to perform loudness metering. The RTW Version 6.0 software, which will be standard on all new 10800X units, enhances the device’s functionality with features including an ITU BS.1770-compliant loudness meter and a quasi-DIN (quasi-analog) bar graph for digital PPM measurements.
Designed to offer users of 10800X and 10860X-VID SurroundMonitor models a way to begin implementation of ITU-compliant loudness metering, the new software offers new functions including an RLB (K) weighting filter as specified by the current ITU recommendation. The filter is available not only for single-channel bar graph meters, but also for dialnorm metering and for the Surround Sound Analyzer. Using an ITU scale in dBLU with positive and negative ranges, the bar graph meter allows the reference level to be set for 0dBLU (-25dBFS to -10dBFS) and the integration times for single-channel view, summed momentary value and Surround Sound Analyzer (125ms to 1.5s). A summed integrated (short-term) measurement with integration times between one and 12 seconds can also be displayed. To exclude low-level modulation portions from the calculation, a gate with variable threshold (-30dBLU to 0dBLU) can be enabled separately.
The Version 6.0 software also comes with the same extra scale for PPM measurement of digital input signals that is now available on other RTW products. The extra scale is quasi-DIN (quasi-analog) scale with a metering range of -60dB to 9dB, where the zero-decibel point is fixed to a digital input level of -9dBFS; thus, a sine-shaped input signal at zero decibels to full scale results in a display value of 9dB. The unit uses a fixed integration time of 10ms. The scale is popular among users because it provides a clipping range above zero decibels, which is familiar from the analog domain. On that scale, even with a fixed integration time of 10ms, an input level set to zero decibels rarely causes digital clipping.