The OPTIMOD 6300 is a high-quality, multipurpose stereo audio processor for digital radio (DAB+, HD Radio), digital television, netcasts, STL protection, satellite uplink protection, and digital mastering.
Background information: What to consider when it comes to Audio Processing for DAB+/Streaming
Thanks to versatile signal routing, the 6300 can also serve as a studio AGC with an all-digital signal path, and simultaneously as a talent headphone processor.
Because all processing is performed by high-speed mathematical calculations within digital signal processing (DSP) chips, the processing has cleanliness, quality, and stability over time and temperature that is unmatched by analog processors.
Absolute Control of Loudness and Peak Modulation
The OPTIMOD 6300 includes third-generation CBS Loudness Controllers™ for DTV applications. Loudness controllers work with the both Two-Band and Five-Band structures. The third-generation improvements reduce annoyance more than simple loudness control alone, doing so without audible gain pumping. Attack time is fast enough to prevent audible loudness overshoots, so the control is smooth and unobtrusive. Material processed by the CBS Loudness Controller has been shown to be well controlled when measured with a long-term loudness meter using the ITU-R BS.1770-2 standard. The 6300 also includes a “BS.1770 Safety Limiter” that follows the CBS Loudness Controller; use the BS.1770 if the BS.1770-2 meter reading must be constrained to a preset value.
The 6300 also implements “True Peak” Control by oversampling the peak limiter’s sidechain at 192 kHz. This allows the 6300 to prevent clipping in a playback device’s analog signal path by predicting and controlling the analog peak level following the playback device’s reconstruction filter to an accuracy of better than 0.5 dB. For typical program material, accuracy is 0.2 dB! Without true peak control, analog clipping can occur even if all peak values of the digital samples are below 0 dBFS. This phenomenon has also been termed “0 dBFS+.”
Thanks to true peak control, sample rate conversion, unless it removes high frequency program energy or introduces group delay distortion, cannot cause sample peaks to increase more than 0.5 dB. For example, sample rate conversion from 48 kHz to 44.1 kHz is highly unlikely to cause sample peak clipping in the 44.1 kHz audio data.
The 6300 includes analog and dual AES3 digital inputs and outputs. The digital input and digital outputs have sample-rate converters and can operate at 32 kHz, 44.1 kHz, 48, 88.2, and 96 kHz sample rates. The pre-emphasis status and output levels are separately adjustable for the analog and digital outputs.
The outputs can be independently configured to emit the output of the AGC or the output of the multiband compressor/limiter, all configurable to use or bypass look-ahead limiting. So a 6300 can be configured to drive an STL with a peak-limited output from the AGC while also providing a fully processed digital radio/netcast feed and a low delay, multiband compressed talent headphone feed.
Adaptability through Multiple Audio Processing Structures
The 6300 features two processing structures: Five-band for a spectrally consistent sound with good loudness control, and Two-band for a transparent sound that preserves the frequency balance of the original program material while also effectively controlling subjective loudness. There are over 60 Factory Presets wich are our “factory recommended settings” for various program formats or types. There are multiple Factory Presets for both radio-oriented and video oriented programming.
Orban’s new PreCode™ technology manipulates several aspects of the audio to minimize artifacts caused by low bitrate codecs, ensuring consistent loudness and texture from one source to the next. There are several factory presets tuned specifically for low bitrate codecs.
The OPTIMOD 6300 Audio Processor can be remote-controlled by 5-12V pulses applied to eight programmable, optically isolated “general-purpose interface” (GPI) ports.
Moreover, because the 6300 supports presets that be recalled by remote control, it can be automatically synchronized to the presets on-air at a transmitter side Optimod when presets are dayparted. The 6300’s software can be upgraded by running Orban-supplied downloadable upgrade software on a PC.