DSPs and audio decoding are critical elements to delivering the type of high quality audio that today’s consumers expect. Today will be the first blog in a series that examines this topic; starting with an overview of why DSPs are critical to audio design.
An infinite number of audio channels are rendered by nature in a truly open space for human ears to enjoy. Scientists and engineers have tried to filter the unwanted, while capturing and reproducing the wanted audio in living rooms. The phonograph, also known by the generic name gramophone provided us a single channel audio just over 140 years ago. Over the years the technology graduated to stereo tapes and multi-channel audio with additional post processing to reproduce audio with highest possible accuracy and fidelity. However, recording audio using discrete microphones and replaying it using discrete speakers brought an unnatural audio experience, forcing technologists to increase the number of channels for recording and playback. This posed yet another problem of recording, transporting and playing the huge amount of data used by a larger number of audio channels. This new problem forced scientists to invent compression/decompression algorithms that did not lose fidelity and dynamic range.
While compressing or encoding the recorded audio channels does not need to be done in real time, as this is accomplished in studios, it is necessary for the decompression or decoding to be done in real time. The advent of digital signal processing (DSP) chips enabled this. Audio from stationary sources such as concert halls, panel discussion, etc., can be handled easily with this method of transporting audio. But most audio that we experience every day is not stationary, be it cars, people walking, or a conversation we walk past. These sounds move in space around us and are thus not so easy to reproduce with discrete speakers without elaborate recording, mixing and playback techniques. Then came the object audio with larger number of channels and virtualization. This further increased the complexity and horsepower requirement on DSPs for decoding and rendering this object audio.
In my next blog, I’ll take a closer look at the performance characteristics of modern DSPs and the importance of having DSPs certified to work with audio decoder IPs to make music for your customer’s ears.