New Upmix / Downmix Solutions Previewed At IBC
Two products previewed by SoundField at this year's IBC complement one another, creating a complete 'set and forget' downmix and upmix audio workflow for high-definition 5.1 surround sound broadcasters. The first is a stereo-to-5.1 upmix processor which creates a fold-down-compatible 5.1 mix from a standard stereo mix like SoundField's existing UPM-1, while the second operates in the other direction, downmixing 5.1 to stereo with the minimum of phase artefacts. Both units may be used in isolation or may be combined to form a complete 5.1-to-stereo-to-5.1 processing combination.
SoundField created the UPM-2 and DWM-2 to aid broadcasters currently making the transition from stereo to discrete-channel surround workflows. At present many stereo editing suites are being used to process 5.1 audio, pending an eventual switch to full editing in surround. With a DWM-2 placed on the 5.1 input to the edit suite and a UPM-2 on the output, the 5.1 surround may be converted to stereo, edited and then re-converted to 5.1 for broadcast using SoundField's transparent upmix/downmix algorithms.
The UPM-2
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The UPM-2 is a 'set and forget' version of SoundField's respected UPM-1 stereo-to-5.1 upmix processor. It uses the same highly effective algorithm as the UPM-1, and has the same complement of inputs and outputs (stereo input and 75ohm AES3 surround outputs on BNC sockets, with wordclock I/O) but has no front-panel controls or displays save status LEDs and metering bar-graphs. Advanced users may access the other, more detailed functions of the UPM-2 via PC-based control software included in the package and connected via the USB socket on the UPM-2's front panel. Once settings have been adjusted, the UPM-2 retains them following disconnection from the computer and may then be used in stand-alone mode.
The DWM-2
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The DWM-2 is the mirror image of the UPM-2, and downmixes 5.1 audio to stereo. It has the same cut-down hardware user interface as the UPM-2, and also offers full control of downmix parameters via USB and the control software.
The UPM-2 and DWM-2 each have three operational modes: Lo/Ro mode, Lt/Rt mode, and SoundField's own Lsf/Rsf mode. The first of these is designed to accept or output audio in simple two-channel stereo, while the second is designed for use with matrix-compatible stereo, as decodable by some AV receivers. These modes are designed for simple, set-and-forget upmix or downmix workflows.
The third mode, Lsf/Rsf mode, is designed for 5.1 audio passing through both units in succession, from 5.1 to stereo and back to 5.1 again. This mode is designed so that 5.1 audio may be downmixed, edited or processed in stereo, and then re-converted to 5.1 for broadcast. Lsf/Rsf mode optimises the audio so that it passes transparently through both conversions.
Opening the door to the complete interoperability of 5.1 and stereo audio in broadcast, the UPM-2 and DWM-2 are scheduled for release early next year.
