Features of QSC/DCP300 Digital Cinema Audio System

In recent years, the film industry is facing the biggest change in a century - digitalization. The filming, production, distribution and screening of movies are gradually shifting towards digitalization and networking. Since the beginning of this century, when movie projection equipment began to be digitized, nearly 10,000 screens around the world have been installed with digital equipment. With the continuous advancement of digital projection technology, the pace of digitalization of cinema equipment will become faster and faster.

In response to the need for digitalization of cinema equipment, various standard organizations in the world have also formulated relevant standards for digital movies. The most representative of these is the "Digital Cinema System Specification" formulated by the Hollywood Digital Cinema Initiative (DCI). The latest version of this specification is V1.2, which was released in March 2008. It also puts forward clear requirements for the audio system of digital cinemas: "The digital cinema processor in the digital movie audio system should receive digital audio from the playback server, then convert it into analog audio signals and distribute them to different speaker channels. The processor is required to be able to receive at least 16 channels of AES digital audio, and at least meet the current movie's 5.1 channels (i.e. left, right, center, sub-bass, left surround, right surround), and can also meet 7.1 channels (adding two main channels of left center and right center compared to 5.1). The remaining audio channels will be used for hearing and visual impairment auxiliary channels or their functions can be customized by users."

The impact of digital networked cinema sound systems on cinema operations

After cinema equipment has entered the digital and networked stage, the most important thing for cinema operation is still the reliability of equipment operation. The stability and reliability of equipment operation is directly related to the cinema operation income and the reputation and word of mouth of the cinema. Whether it is projection equipment or audio equipment, or even the lighting or screen system in the theater, any failure in any link will affect the screening of the film, and in serious cases will cause suspension of the show or refund of tickets, which will directly affect the cinema's operating income, and indirectly affect the audience's bad impression, thus affecting the long-term operation of the cinema.

As the core of the cinema audio system, the cinema audio processor is of utmost importance. Imagine if the audience is concentrating on watching a movie and suddenly there is no sound, what will the scene be like? Therefore, for the cinema audio processor, the stability and reliability of the equipment are crucial, and there must be corresponding emergency measures for sudden failures to ensure the normal screening of the film.

In addition, in today's digital and networked world, the previous working mode of cinemas is also facing changes. When the projection and sound reproduction equipment of cinemas are all digitized, cinemas will have the technical basis for centralized control of all equipment through the network. There will no longer be a need for too many projectionists in the projection room. Only one person can complete the work that currently requires multiple people to complete by sitting in the central control room. A time schedule can be set for the film projection, sound control, and lighting and curtain control of all theaters, and then the control computer will operate at a fixed time. The projectionist only needs to monitor the working status of various equipment in the central control room. With the increase in labor costs in China, this will also provide a new way for cinemas to save operating costs.

Features of QSC Digital Cinema Audio Systems

QSC is a leader in the professional audio industry in the United States with a history of more than 40 years. It is committed to providing professional power amplifiers, cinema speakers and professional sound reinforcement speakers, various digital audio processors, and complete network audio matrices and other audio system solutions to users around the world. Its audio equipment in the cinema field has nearly half of the market share in the United States, and it is also a leader among imported brands in the Chinese market. This article will focus on the relevant information of QSC cinema products, so that everyone can understand the different solutions for digital cinemas.

Cinema audio equipment mainly includes audio processors, speakers, amplifiers and other products, and digital cinema is no exception. QSC is the only well-known manufacturer in the market that can provide users with complete digital cinema audio system solutions. This is one of the reasons why we choose QSC as an example for introduction.

Let's first talk about the "heart" product - the processor. To meet the needs of digital cinema construction, QSC took the lead in launching the digital cinema processor DCP300 in 2009, which can fully meet the DCI standard and is the core of the digital cinema solution. The cinema audio system with DCP300 as the core has many outstanding advantages:

Features of QSC Digital Cinema Audio Systems

1. Taking the long-term interests of customers into full consideration, the entire system is designed according to the latest DCI digital cinema system specifications, which not only meets the needs of current digital film audio systems, but also meets the needs of digital film audio systems in the next ten years or even longer, so as to reduce the increased costs of cinemas due to equipment upgrades.

2. Equipped with powerful digital signal processing (DSP) functions and a built-in speaker parameter database, it connects the theater processor and amplifier via a data cable, greatly simplifying the installation, wiring and debugging process of the theater audio system. Users can directly call the speaker model and parameters during installation and debugging, and then quickly and carefully adjust the entire audio system and sound field according to specific circumstances.

3. Network monitoring and management functions, staff can operate and manage all equipment through the network. Since most of the current commercial cinemas are multi-hall cinemas, cinema staff need to manage the equipment of all theaters in a unified manner. Through the network, they can check the operating status of the equipment at any time, whether in the computer room or in the manager's office, and perform different operations according to different permissions.

4. For the first time, the concept of network audio transmission was introduced into the cinema audio system. The CobraNet technology, which has been maturely applied in the sound reinforcement system, was used to establish the cinema's network audio transmission system, laying a good technical foundation for the centralized management and network management of the cinema.

5. Integrate QSC's traditional advantage products, such as cinema speakers, cinema amplifiers and cinema processors, into a complete system to provide customers with comprehensive and seamlessly integrated system solutions, thereby minimizing the subsequent equipment maintenance costs for customers.

Features of DCP300 Digital Cinema Processor:

1) Rich interfaces:

DCP300 takes into account the development needs of future digital cinema audio systems as well as the current status of cinema equipment. Therefore, the DCP-300 main input is equipped with 8-channel analog audio input interfaces and 16-channel AES digital audio input interfaces. In addition, it is also equipped with S/PDIF digital input, universal microphone/cable input, asynchronous stereo input and other interfaces to adapt to other different program sources.

In terms of control interface, DCP300 is equipped with USB interface and 100M Ethernet network interface for debugging and monitoring. It is also equipped with automation control input, logic output and relay output for use in conjunction with theater automation control systems to achieve automatic operation of lighting, screen and other systems during film screenings.

Rich interfaces

2) Powerful digital signal processing capabilities:

DCP-300 has a built-in powerful DSP digital signal processing engine, which is mainly used to adjust the sound field of the theater and distribute the audio signals of the speakers. Among them, its built-in electronic crossover can process all main channels with 2-way, 3-way and 4-way, and also supports passive crossover (processed by the speaker's own crossover) mode. The above-mentioned crossover modes can define the crossover mode and crossover point of the speaker by yourself, or select the corresponding speaker model from the processor's internal speaker database. In addition to the parameters of all QSC's DCS cinema speakers, the speaker database also contains the relevant parameters of most mainstream brands of cinema speakers, which users can directly call.

In addition to the frequency division processing function, DCP-300 can also perform independent signal processing on all audio channels. Each channel includes a 1/3 octave graphic equalizer, parametric equalizer, filter, polarity setting, delay adjustment and gain control, etc. The installation and debugging personnel can complete all equipment debugging work in front of the computer.

3) Network monitoring function:

The DCP-300 digital cinema processor and DCA series digital cinema amplifier can realize the centralized management and network monitoring function of the cinema. It is based on QSC's mature QSControl.net system platform and is specially developed for cinema systems. The QSControl.net platform is based on a common 100M Ethernet network and can monitor the detailed device status of all audio devices in the system through the network, including the status of the amplifier and the working status of the speaker load.

Network monitoring function

The built-in monitoring speaker of DCP-300 can monitor the signal input and amplifier output of all audio channels in the theater. It can detect whether there is any abnormality in the sound in the theater at any time, and can quickly determine which channel and what link has the abnormality.

DCP-300 can connect to DCA digital cinema amplifiers via DataPort data cables and obtain the working status of the amplifiers and speakers, such as the operating temperature of the amplifier, whether the amplifier is clipping, whether it is in protection status, the model of the amplifier, as well as the operating voltage, current and power, control the power on and off of the amplifier, the impedance of the speaker, open circuit or short circuit status, etc.

The above-mentioned signal monitoring and working status monitoring can be reported to the central control computer through the 100M Ethernet network, and an alarm can be issued when a fault occurs. The monitoring personnel can discover the problem in time and accurately determine which theater or even a channel of a power amplifier has a fault, so that the problem can be solved quickly and accurately.

QSC also designed the wall-mounted network controller NAC-100, which is used to control the entire audio system of the cinema at any location in the network. It uses network POE power supply and can be used by simply plugging in the network cable. It can be installed anywhere in the cinema's machine room, manager's office, theater entrance, etc. Through it, theater staff can choose any theater to control, such as adjusting the volume, or even controlling the lights in the theater.

Network Controller NAC-100

The QSControl.net system allows users to create their own control interface, and selectively display the content that users need to monitor on the computer screen, rather than all the content. At the same time, the QSControl.net system can set permissions for operating users, and the operations that different levels of staff can perform are also different. For example, the projectionist can only view the working status of the current equipment and change the sound volume in the theater; in addition to the above rights, the projection manager can also view the system log, select the sound format, and check the status of all equipment.