Audio Signal Processing
- By David Kirk
Contributing Editor David Kirk’s summarises recent developments in audio signal handling and analysis…
This overview looks at new developments in broadcast audio signal processors, a subject currently dominated by the ever wider adoption of IP networking.
2wcom’s IP-8m audio-over-IP codec allows the transmission of eight channels in phase-locked mode (8.0, 7.1 or 6.0 and 2.0; 5.1 and 2.0; or 4.0 and 4.0). It can also be operated in 6+2 channel or 4+4 channel mode.
Suitable for audio broadcast applications such as live concerts and studio-to-studio connections, it gives operators a choice of audio algorithms, including Dolby Digital (AC-3), Dolby Digital+ (DD+ or E-AC-3), PCM, E-aptX, and AAC.
The codec is compliant with EBU Tech 3326, AES67, Ravenna, Livewire+ and SMPTE 2110. Features include Pro-MPEG FEC or SRT error correction mechanisms, streaming redundancy, audio backup and dual power supplies All parameters can be configured through a web interface or SNMP, Ember+ or JSON. An SIP phonebook simplifies intercommunication for remote connections by negotiating protocols and codec algorithms with one click. Network Time Protocol, PTPv2,or 1PPS allow a synchronized playout.
Cobalt’s 9934-AUD-PRO-DSP audio processor has an integral mixer and AES/analog codec. Included standard are bulk and per-channel audio delay controls to address lip-sync issues. Option +TTS converts EAS text to digital audio speech. Options include Dolby Real-Time Loudness Leveling automatic loudness processing, Dolby encode/decode, and Linear Acoustic Upmax automatic upmixing.
Comrex’ Access MultiRack is a 1 RU IP audio processor handling up to five full-duplex IP audio channels. It is compatible with all Comrex IP audio codecs as well as the Comrex FieldTap mobile phone app. AES67-compatible I/O is provided on all codec channels, along with AES3 and analog I/O on the first channel.
Digigram’s Iqoya Talk portable IP audio codec allows mobile live reporting or commentary as well as studio interviews. Features include three mic/line inputs, an 11 input mixer, integral audio recorder and 4G/LTE streaming.
Orban Labs has added Nielsen Portable People Meter encoding to its XPN-AM processor. Developed by Arbitron (now Nielsen Audio), the allows the number of people exposed to or listening to individual radio stations and television stations, including cable television, to be measured. The PPM is worn like a pager and detects hidden audio tones within a station or network’s audio stream, logging each time it finds such a signal. The XPN-AM is based on an AM-optimised version of Orban’s MX limiter technology first introduced in the Optimod-FM 8600.
Sonifex’ AVN-DIO10 is a 3G/HD/SD-SDI to Dante embedder/de-embedder. It takes any SDI feed, de-embeds the 16 audio channels and places them on channels 1-16 of the Dante network, mapped using Dante Controller. It simultaneously takes the 16 input channels mapped to the device on Dante Controller and re-embeds them onto the SDI output, with an embed enable switch for each channel pair. The unit has a single 3G/HD/SD-SDI input and a reclocked output, with dual redundant Primary and Secondary Dante network ports, using Neutrik EtherCon Ethernet connectors.
Systembase’s C510ip-s IP audio codec is designed for IP, ISDN, ADSL and satellite applications. It incorporates apt-X sub band ADPCM compression and is fully compatible with the existing C310xr ISDN codecs when operating over ISDN and X.21 circuits. The C510ip-s also supports Dual G.711 and Dual G.722 coding to provide enhanced compatibility with third-party ISDN codecs from other manufacturers. Additional features include 24 bit analogue and AES audio interfaces. Following a power failure, C500 series codecs can fully reboot to the ready state in approximately 1 second. All Systembase C500 series codecs can be monitored from a browser window. Each codec icon allows the user to monitor the audio input and output levels together with the sync status of the codec.
Telos has been making improvements to its Infinity IP Intercom. Link Lite is a new VoIP-only mode for panels and beltpacks enables the user to connect remotely via the internet. It automatically activates Link channels (two per beltpack and eight per master panel). Telos Infinity panels now support SMPTE ST2022-7 seamless protection switching. Dashboard Application is a standalone PC program for systems of 4, 8, 16, or 24 devices. All features are common across the Dashboard system.
