Digital signal processors: small chips with big talent
Areas of application and advantages of DSPs in PA technology
They are now installed almost everywhere: in computers, cell phones and also in audio technology – digital signal processors. Although the tiny chips seem inconspicuous at first glance, they can do a lot. In PA technology, they enable you to easily edit audio signals and optimise sounds. And this even in acoustically challenging environments such as large halls. We explain what you need to know about digital signal processors and what advantages the microchips have for you.
This is a digital signal processor (DSP)
The digital signal processor, also called DSP, is a specialised microchip that continuously receives and processes digital signals.
In audio technology, you can find DSPs in speakers, mixers, systems or separately as a small device ]. Here the small chips process and optimise digital audio signals.
You operate the DSPs using special computer programs or hardware. But how does digital signal processing work in PA technology?
The three steps of digital signal processing
From analogue to digital: The name gives it away – DSPs only process digital signals. Analogue audio signals (e.g. from a microphone must first be converted into a digital signal. An A/D converter(analogue to digital converter) samples the analogue signals and translates them into digital values. A digital audio signal is created.
Signal processing: the digital signal reaches the DSP. Using algorithms, the processor analyses the audio signal and can modify and optimise it. For example, the DSP adjusts the volume of the audio signals and transmits a modified digital audio signal.
And back again: digital signals are just code, a huge amount of ones and zeros, and therefore not audible. A D/A converter converts the digital audio signal so that it fits back into our analogue world. We hear the modified sound amplified and played through speakers.
And how can you specifically use DSPs in PA technology?
Six areas of application of DSPs in PA technology
1. Sound optimisation
DSPs offer you many options for processing audio signals. Here are some options:
Equalising: individual frequencies can be raised or lowered using DSPs. This is particularly interesting for various acoustic scenarios.
Time delay: DSPs use a transit time delay to synchronise signals with each other.
Dynamic processing: DSPs enable limiting and compression of sounds.
Noise suppression: The DSP's algorithms detect unwanted noise and filter it out of the audio signal.
Using these tools, you can easily modify and optimise the sounds– just the way you want it. This is particularly helpful if you want to adapt the sound to a specific acoustic situation, for example an event hall. DSPs make an ideal sound experience possible in numerous environments.
2. Feedback cancellation
When a microphone is used in an audio system, sometimes unwanted feedback occurs – you can easily prevent this with DSPs. The microchips continuously scan the audio signal. The algorithm can then react quickly to feedback and compensate for it. This ensures that the sound quality is not affected.
3. Space optimisation
However, the numerous processing options are not the only features that DSPs offer: some of these chips can analyse spaces and automatically adapt the audio signals to the environment. This involves taking many measurements at different points in the room, analysing them and calculating a correction.
Acoustically difficult environments are no longer a problem with DSPs.
Not all DSPs can automatically adjust the sound to the acoustic conditions. You therefore also have the option of manually modifying parameters such as running time and frequencies via the DSP. This means you can ensure consistent PA application even in challenging environments such as a shopping centre.
Delayingand DSPs
In audio systems with several speakers, the DSP can delay the sound of individual speakers. This creates a better sound even in difficult acoustic environments. In lecture halls delaying can, for example, improve speech intelligibility.
4. Management of multi-channel systems
DSPs are also part of many multi-channel audio systems. The microchip controls the interaction of the various channels and can adjust their sound individually. This means you can easily manage complex audio systems via DSPs – without connecting a lot of hardware.
5. Speaker management
There's even more to these little chips: DSPs precisely adjust crossover networks or the level of a speaker. In this way, the microchips ensure optimal speaker performance.
6. Live sound
DSPs are a great help, especially when live sound is involved: by continuously monitoring and adjusting the signals, the microchips can identify and resolve any problems that arise spontaneously – without long time delays. DSPs also allow you to quickly react to changes in the acoustic environment and adapt the sound.
Find out more about interesting and helpful aspects of audio technology in our magazine
Four advantages of DSPs in PA technology
DSPs are used in a variety of ways in PA technology – and make the work of planners and installers easier. The small chips have a number of advantages:
1. Optimum sound with DSPs
DSPs are precise: they can be used to modify and control audio signals according to your liking. They compensate feedback, remove unwanted interference, analyse acoustic conditions and adapt the volume and frequencies.
This allows you to improve the sound quality and adapt it to specific situations – for optimum sound in all environments. And even the processing is flexible.
2. No need to replace hardware – Flexibility thanks to DSPs
With DSPs, you don't have to replace hardware components if you want to change something in your audio system:
Sounds can be flexibly adapted: you can also adjust frequencies and dynamics using the DSP after the audio system has been set up.
Configuration also becomes easier: DSPs are a great help when setting up audio systems. You can combine audio sources and speakers and control them as desired using DSPs. The system configuration is also more flexible, as you can make changes at a later stage – without having to replace hardware.
3. Real-time processing enables quick adaptations
The use of DSPs is appropriate, especially for time-critical applications. By continuously analysing the signal, unwanted interference can be removed without a long time delay. This is an advantage, for example, at conferences with lectures, as you can edit the live audio in real time and thus optimise the sound.
4. Microchips for greater efficiency
DSPs automate many tasks and functions and allow adaptations without the need to replace hardware. This saves you time and resources. For example, if you are setting up audio systems, you can download user-defined configurations and do not have to adjust all the settings manually. DSPs also offer efficient troubleshooting: by continuously analysing the digital signal, you can quickly identify problems and eliminate them immediately.
Challenges of DSPs
DSPs also have certain limitations. Due to the digital processing of the audio signal, analogue characteristics of the sound can be lost. For commercial purposes, the positive effects of DSPs such as efficiency, flexibility and a wide range of processing options prevail. Whether the sound has analogue properties is less relevant.
Since you can manipulate sounds in a variety of ways through DSPs, there is also a certain complexity associated with the use of the microchips. You first need to familiarise yourself with how DSPs work in order to make the most of these small chips. But with a little practice, you can take full advantage of DSPs.
Conclusion: DSPs are multi-talents in PA technology
You can use the inconspicuous microchips in a variety of ways: you can optimise sound through equalisation or dynamic processing, manage speaker systems, provide rooms with consistent sound, suppress feedback and monitor live sound. As a result, DSPs increase your efficiency and make your work more flexible.
Headergraphik: Adobe Stock Aliaksandra
