Discussion on ways to listen to light show music on cruise ships

There are many ways to listen to music synchronized with the light show on a cruise ship, each with its own pros and cons. The stability, synchronization and sound quality of listening to music have always been the focus of the operation and maintenance unit. A more stable, better synchronized, and better sound quality method can reduce the occurrence of performance accidents and greatly improve the visitor's perception. This article compares the advantages and disadvantages of several ways to synchronize music with light shows on cruise ships, and it can be found that the method of remotely triggering local playback has advantages over the other methods in terms of stability, synchronization, and sound quality.

With the rapid development of electronics, computers and networks, sound signal transmission is changing from traditional analog signals to digital signals. During the transmission of analog signals, noise will be amplified, which will have a greater impact on the quality of signal transmission. Digital signal transmission has strong anti-interference and anti-noise capabilities, but it is not suitable to use wired transmission methods such as optical fiber and coaxial cable to transmit audio signals to the cruise ship. If the network is used for transmission, the delay is high, resulting in the sound and light show being out of sync. This requires a new way to make listening to music synchronized with the light show on a cruise ship more stable, with better synchronization and better sound effects.

1. Common ways to listen to light show music on cruise ships

1.1 Use FM radio to listen to light show music

Required equipment and conditions: control room video host, FM radio transmitter, antenna, wireless receiver, sound system equipment.

This method plays the original light show music file from the video host in the control room. After the audio signal output by the video host is processed by the audio processor, the FM broadcast transmitter first modulates the audio signal and high-frequency carrier wave into an FM wave, so that the frequency of the high-frequency carrier wave changes with the audio signal. The generated high-frequency signal is then amplified, excited, powered by a power amplifier and matched with a series of impedances, and then the signal is output to the antenna and sent out in the form of electromagnetic waves. After the wireless receiver on the cruise ship receives the electromagnetic wave signal from the transmitter through the receiving antenna, it selects the signal of a specific frequency through the resonant circuit, performs resonance amplification, and then restores the high-frequency signal to the original audio signal through frequency conversion and demodulation. After the restored audio signal is processed by the audio processor on the cruise ship, the signal is amplified through the power amplifier, and finally drives the speaker to output music.

Advantages:

1) The signal is transmitted in real time, and the music can continue to be synchronized after the failure is restored.

2) Wide coverage, easy installation and maintenance.

Disadvantages:

1) Poor anti-interference ability, noisy, and poor sound quality.

2) The transmission distance is short and audio signals are sent in the form of electromagnetic waves, which are easily blocked by large obstacles.

1.2 Use Dante digital audio transmission technology to listen to light show music

The Dante protocol is a modern high-performance digital media transmission system running on a standard IP network. It was developed by Audinate in 2003. Like the traditional CobraNet technology, it is also a product integrating hardware, software and communication protocols. Dante is a layer-3 IP network technology that provides a low-latency, high-precision and low-cost solution for point-to-point audio connections. Dante technology can transmit high-precision clock signals and professional audio signals on Ethernet (100M or 1000M) and can perform complex routing.

Required equipment and conditions: control room video host, network switch, 4G router, APN network, digital audio processor supporting Dante technology, and sound system equipment.

This method plays the original light show music file from the video host in the control room. The audio signal is converted into a UDP/IP network signal through the video host and transmitted to the network. The audio signal is routed in the form of data packets through the APN network to the 4G router on the ship. It is then processed by an audio processor that supports Dante digital audio transmission technology to restore the network signal to the original audio signal. The signal is then amplified through a power amplifier, and finally drives the speaker to output music.

Figure 2: Digital audio transmission system diagram

Advantages:

1) The signal is transmitted in real time, and the music can continue to be synchronized after the fault is restored.

2) Strong anti-interference ability, digital audio signal transmission based on the network, completely getting rid of the problem of being susceptible to other electromagnetic interference from the environment during the analog signal transmission process.

3) The installation and wiring are simple, the design and networking are easy to implement, and the debugging and monitoring are convenient, which reduces the cost.

Disadvantages:

1) There is network delay, which causes the light show and sound to be out of sync, and the sound is delayed compared to the light show.

2) Real-time signal transmission consumes a large amount of traffic and requires high bandwidth, which can easily cause network congestion.

The above two methods are the most commonly used ways to receive light show music on night cruises. By comparison, we can find that these two solutions have some shortcomings in terms of applicability, synchronization, sound quality, etc. So is there a way to ensure that the music and light show content are synchronized and the sound quality is better?

2. Use remote triggering to play the light show music locally

Required equipment and conditions: video host in the control room and supporting main control software, video host on the cruise ship and supporting node software, network switch, 4G router, APN network, and sound system equipment.

This method stores the original files of the light show music playback on the video host on the cruise ship. After the software and network of the video host in the control room and the video host on the cruise ship are configured, the video host in the control room uses the supporting main control software and the APN network to remotely trigger the Cuelist of the light show music stored in the supporting node software of the video host on the cruise ship through the UDP protocol to play the local light show music on the cruise ship video host. When there are multiple cruise ships watching the light show together, the IP addresses of the video hosts on all cruise ships can be entered into the IP table of the video host master control software in the control room, thereby triggering the light show music on multiple ships at the same time. The light show music of the designated ship can also be triggered individually through settings. The video host on the cruise ship outputs the audio signal to the audio processor through the 3.5mm or USB sound card. After the audio signal is processed by the audio processor, the signal is amplified through the power amplifier and drives the speaker to output music.

Figure 3: Remotely triggered local playback system diagram

Advantages:

1) It has strong anti-interference ability. By remotely triggering local playback, it completely gets rid of the problem of being susceptible to other electromagnetic interference in the environment during analog signal transmission, and the sound quality is good.

2) There is no delay in local playback, and the light show and music are synchronized.

3) Remotely trigger local playback in the form of data packets, which only requires very little traffic when triggered, has low bandwidth requirements, and will not cause network congestion.

4) The installation and wiring are simple, the design and networking are easy to implement, and debugging and monitoring are convenient.

Disadvantages:

1) Due to poor signal or network packet loss, there is a small chance that the trigger signal will not be received on the cruise ship and the music will not play properly.

2) The signal is not transmitted in real time, and the music cannot remain in sync after a failure is restored.

Although the remote triggering of local playback has a small probability of triggering failure and causing the music on the cruise to not play normally, we can greatly reduce the probability of triggering failure by enhancing the network signal at the cruise viewing point and using a more stable control system, and can even almost avoid triggering failure. In case the music is not triggered normally due to network packet loss, we can directly open the light show audio file in the video host on the cruise ship, pull the timeline of the audio file back to a suitable position, and immediately play it manually when the light show reaches this position, so that the light show and the music can be synchronized again. In this way, after performance problems occur, we can make timely adjustments so that the performance can continue to run synchronously and normally. In addition, when the network fails and cannot be restored in time, we can also manually play the light show music from the cruise ship. The person who plays the light show in the control room and the person who plays the light show music on the cruise ship are contacted by phone or intercom, and the light show and light show music are played manually at the same time.

3. Conclusion:

By remotely triggering local playback of the light show music on the cruise ship, the network delay can be greatly reduced, synchronizing the light show with the music on the cruise ship, avoiding network congestion, greatly improving the sound quality, and making installation, debugging and monitoring very convenient. When problems such as trigger failure or network failure occur, there are also corresponding emergency remedies. This method has been used in many night tour performance projects. It has been verified that it is a good solution for playing light show music on cruise ships in night tour projects and is worthy of promotion and discussion.