Sonos4

Sonos 4 central feature is a state of the art software multiband compressor limiter (MBL9) for radio broadcasters. With this software and a suitable sound card it is possible to turn a Windows PC into an radio broadcast processor. The processor achieves its punch (loudness) through the use of a unique distortion masked final clipper. The software is for all forms of broadcasting such as AM,FM,DAB and Internet streaming. Sonos 4 interfaces to sound cards using either ASIO or the Windows native multimedia sound interface. If the ASIO interface is used then low latency mode can be used. Use of ASIO is dependent upon the sound card having ASIO drivers. Most 'Pro' sound cards support ASIO.Low latency mode enables off air monitoring while speaking just as hardware FM & AM processors do. Sonos 4 supports multiple instances. It is theoretically possible to have multiple processors (up to eight) but CPUs are not fast enough yet to support eight processors. Current quad cores will just about support two instances of MBL9.(The nine band processor). The processor is the central feature of Sonos 4.There is a choice of four band,five band,six band,nine band and nine band wide bandwidth processors. The nine band (MBL9) is the recommended choice but it may overload some computers so to reduce CPU load a processor with fewer bands can be selected. All five processors share common parts such as three stages of parametric equalization, stereo widener, stereo enhancer,phase rotator, filtering for FM and AM, switchable pre-emphasis for FM. The processor architecture is similar in each of the five processors. Single dual or tri band gated AGC is followed by a gated multiband limiter optionally preceded by a multiband compressor. Single band gated limiting is applied before the final clipper. Pre-emphasis for FM is applied partially before the multiband section and partially after the final clipper. The processor settings are fully adjustable with easy to use saving and loading of preset files. There is a 'Daypart' scheduler to enable changes of preset (format) by time of day and day of the week. The processors have a 'Fail Over' or failsafe feature that switches the input to a backup should the main source fail. If the processor is not being used it can be disabled to reduce CPU load.
It is possible to drive FM transmitter MPX inputs directly from Sonos 4.It needs a 192kHz sound card with adequate bandwidth to pas the MPX signal. The stereo multiplex encoder has adjustable clipping for extra loudness.The pilot tone amplitude is adjustable. The RDS/RBDS encoder supports all the basic RDS features plus it has a scrolling 'Program Service Name' feature with multiple messages that can be set up as a rotation. SCA generator supports frequencies from 20kHz to 90kHz and deviation from 1kHz to 10kHz.