But what is DSP, how does it work, and what happens to the music when processed? I wanted to find out so I approached our Chief Technology Officer, Jan Abildgaard Pedersen, to learn more about the technology.
[Christopher Kjærulff, Content Manager] Hi Jan, thanks for taking the time to sit down with me. So, we use DSP in some of our products such as the Xeo series, Focus XD series, and in many of our professional products, but what is it? Can you, in your words, describe what DSP is?
[Jan Abildgaard Pedersen, CTO] No, problem. It’s my pleasure. Digital signal processing – or more commonly known as DSP – is the numerical manipulation of signals and we do it in a computer of sorts; a microprocessor specifically developed to do complex calculations extremely quickly.
We work with a huge amount of data and complexity, and the regular household computer just cannot process it, so that’s where DSP comes into play: it’s a microprocessor that excels at doing multiplications and additions in nanoseconds.
High-resolution audio is sampled 192,000 times each second, and we work in stereo, so we get two numbers every 192,000-part of a second. All that information is processed in the DSP: calculated, filtered, manipulated – and it offers us complete control over the process and a sea of opportunities.
However, there’s a saying in our business: “the DSP engineer does not know the problem but has the solution. The acoustician knows the problem but can’t imagine the solution, so he doesn’t ask the DSP engineer.”
You need to master the interdisciplinary field of DSP and acoustics. If you don’t, you might develop solutions for problems that don’t exist or neglect to fix a problem because you didn’t know the solution existed.
Because we focus on this interdisciplinarity, we can use the possibilities in digital signal processing to enhance the quality of our sound:
Obviously, it’s a huge benefit being able to offset irregularities, preventing loss of information, etc.? But, could you expand a little more on the benefits of doing so?
If I ask you to paint a replica of a famous painting, you might be able to reproduce some of the essentials: shapes, colors, etc. But it would be difficult to reproduce the artist’s brushstroke, the small details, the right color variations: the things that add clarity.
But, if I asked you to copy a sequence of 20 numbers, you could do so without losing any information in the process.
What we are doing in the analog domain somewhat resembles making a replica of a complex painting whereas working with a sequence of numbers is what we do in DSP.
We transmit zeroes and ones: voltage or no voltage. When we started with DSP, a one was anything above 2.5V, and a zero anything below – the maximum was 5V. If we transmit a one, we would send a 5V signal through the cable and receive, let’s say, 4.1V due to resistance in the cable – a significant loss, but still very clearly a one. And, the receiver wouldn’t resend it as a 4.1V signal, because it recognized it as a one and therefore sends 5V. The receiver only needs to differentiate between zeroes and ones.
There is no loss of information.